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Background: The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) causes a respiratory illness, characterized by symptoms such as fever, dry cough, and drowsiness. This virus is highly contagious, has significant mutation rates, and induces infection despite vaccination. Its widespread prevalence has profoundly impacted global economies, societies, and daily life. In response to these challenges, researchers have committed themselves to advancing rapid and cost-effective diagnostic technologies, holding substantial importance for the rapid evolution of global diagnostic capabilities. Nonetheless, various detection methods diverge in principles, sensitivity, specificity, and other aspects. Additionally, COVID-19 is not an isolated event, but part of a broader history of pandemics in human society. Therefore, this article briefly reviews the existing detection methods of SARSCoV-2, providing valuable technical insights to diagnose not only SARS-CoV-2 but also other viruses. Methods: A search was conducted on PubMed by utilizing keywords such as "SARS-CoV-2 detection", "RTqPCR detection for SARS-CoV-2", "LFA detection for SARS-CoV-2", "Biosensors detection for SARS-CoV-2", and similar terms. The objective was to compile and summarize relevant articles on these topics. Results: Currently, the real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR) stands as a widely employed method for detecting SARS-CoV-2, enabling an accurate detection of viral RNA. Furthermore, the lateral flow assay (LFA) assists in detecting viral antigens and antibodies. Gene sequencing technology primarily facilitates the real-time monitoring of mutated SARS-CoV-2 strains, while biosensors could offer a rapid, economical, sensitive, and precise detection of SARS-CoV-2. These methods provide a strong technical support for the early detection and diagnosis of SARS-CoV-2. Conclusions: This paper offers a concise overview of pathogen detection methods, as molecular biology, and immunological detection techniques, alongside emerging biosensor platforms relevant to SARS-CoV-2, and delineates the strengths and weaknesses of each method. [ABSTRACT FROM AUTHOR]

How different classes of the B cell antigen receptor (BCR) sense viral antigens used in vaccination protocols is poorly understood. Here, we study antigen binding and sensing of human Ramos B cells expressing a BCR of either the IgM or IgG1 class with specificity for the CD4-binding-site of the envelope (Env) protein of the HIV-1. Both BCRs carry an identical antigen binding site derived from the broad neutralizing antibody (bnAb) CH31. We find a five times higher expression of the IgG1-BCR in comparison to the IgM-BCR on the surface of transfected Ramos B cells. The two BCR classes also differ from each other in their interaction with cognate HIV Env antigens in that the IgG1-BCR and IgM-BCR bind preferentially to polyvalent and monovalent antigens, respectively. By generating an IgM/IgG1 chimeric BCR, we found that the class-specific BCR expression and antigen-sensing behavior can be transferred with the CH1γ domain from the IgG1-BCR to the IgM-BCR. Thus, the class of CH1 domain has an impact on BCR assembly and expression as well as on antigen sensing. [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated the efficacy and feasibility of an anti-viral vaccine strategy that takes advantage of pre-existing CD4+ helper T (Th) cells induced by Mycobacterium bovis bacille Calmette-Gue'rin (BCG) vaccination. This strategy uses immunization with recombinant fusion proteins comprised of a cell surface expressed viral antigen, such as a viral envelope glycoprotein, engineered to contain well-defined BCG Th cell epitopes, thus rapidly recruiting Th cells induced by prior BCG vaccination to provide intrastructural help to virusspecific B cells. In the current study, we show that Th cells induced by BCG were localized predominantly outside of germinal centers and promoted antibody class switching to isotypes characterized by strong Fc receptor interactions and effector functions. Furthermore, BCG vaccination also upregulated FcgR expression to potentially maximize antibody-dependent effector activities. Using a mouse model of Ebola virus (EBOV) infection, this vaccine strategy provided sustained antibody levels with strong IgG2c bias and protection against lethal challenge. This general approach can be easily adapted to other viruses, and may be a rapid and effective method of immunization against emerging pandemics in populations that routinely receive BCG vaccination. [ABSTRACT FROM AUTHOR]

Adoptive cell therapies (ACTs) have revolutionized cancer immunotherapy, prompting exploration into their application against oncoviruses. Oncoviruses such as human papillomavirus (HPV), hepatitis B virus (HBV), hepatitis C virus (HCV), and Epstein-Barr virus (EBV) contribute significantly (12-25%) to human malignancies through direct or indirect oncogenic mechanisms. These viruses persistently or latently infect cells, disrupt cellular homeostasis and pathways, challenging current antiviral treatment paradigms. Moreover, viral infections pose additional risks in the setting of long-term cancer therapy and lead to morbidity and mortality. Virally encoded oncoproteins, which are tumor-restricted, immunologically foreign, and even uniformly expressed, represent promising targets for patient-tailored ACTs. This review elucidates the rationale for leveraging viral antigen-specific ACTs in combating viral-associated malignancies. On this basis, ongoing preclinical studies consolidate our understanding of harnessing ACTs against viral malignancies, underscoring their potential to eradicate viruses implicated in cancer progression. Furthermore, we scrutinize the current landscape of clinical trials focusing on virus-specific ACTs and discuss their implications for therapeutic advancement. [ABSTRACT FROM AUTHOR]

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), long COVID (LC) and post-COVID-19 vaccine syndrome show similarities in their pathophysiology and clinical manifestations. These disorders are related to viral or adjuvant persistence, immunological alterations, autoimmune diseases and hormonal imbalances. A developmental model is postulated that involves the interaction between immune hyperactivation, autoimmune hypophysitis or pituitary hypophysitis, and immune depletion. This process might begin with a deficient CD4 T-cell response to viral infections in genetically predisposed individuals (HLA-DRB1), followed by an uncontrolled immune response with CD8 T-cell hyperactivation and elevated antibody production, some of which may be directed against autoantigens, which can trigger autoimmune hypophysitis or direct damage to the pituitary, resulting in decreased production of pituitary hormones, such as ACTH. As the disease progresses, prolonged exposure to viral antigens can lead to exhaustion of the immune system, exacerbating symptoms and pathology. It is suggested that these disorders could be included in the autoimmune/adjuvant-induced inflammatory syndrome (ASIA) because of their similar clinical manifestations and possible relationship to genetic factors, such as polymorphisms in the HLADRB1 gene. In addition, it is proposed that treatment with antivirals, corticosteroids/ginseng, antioxidants, and metabolic precursors could improve symptoms by modulating the immune response, pituitary function, inflammation and oxidative stress. Therefore, the purpose of this review is to suggest a possible autoimmune origin against the adenohypophysis and a possible improvement of symptoms after treatment with corticosteroid replacement therapy. [ABSTRACT FROM AUTHOR]

We propose a modified general model of mixed infection that takes into account the influence of diffusion perturbations and interactions between antigens on the development of the disease. To find the solution of the original model problem with delay, we develop a special step-by-step procedure for the numerical asymptotic approximation of the solution to the corresponding sequence of singularly perturbed problems without delay. The results of computer simulations illustrate the expected exacerbation of the main chronic disease in the case of additional infection of the body by another (more intense) viral infection. It is shown that the process of diffusion "scattering" of antigens leads to a model decrease in their concentration in the infected area and, hence, to a decrease in the total "acuteness" of the biinfection. It is also shown that the effect of diffusion "scattering" leads to a decrease in the range of model values of the concentration of antigens of chronic disease observed when the rate of damage to the cells of the target organ by antigens of the additional viral infection varies within a specified range. This is important for the efficient prediction of the dynamics of disease in specialized decision-making systems and for the formation of appropriate individual treatment programs in the cases where additional complications are caused by the penetration of additional viral infections into the body. [ABSTRACT FROM AUTHOR]

Introduction: Latent tuberculosis infection (LTBI) is a common coinfection in people living with HIV (PWH). How LTBI and HIV exposure in utero influence the development of infant humoral immunity is not well characterized. To address this question, we assessed the relationship between maternal humoral responses in pregnant women with HIV or with HIV/LTBI on humoral responses in infants to BCG vaccination and TB acquisition. Methods: Plasma samples were obtained from mother infant pairs during pregnancy (14-34 wks gestation) and in infants at 12 and 44 wks of age from the IMPAACT P1078 clinical trial. LTBI was established by Interferon gamma release assay (IGRA). Progression to active TB (ATB) disease was observed in 5 women at various times after giving birth. All infants were BCG vaccinated at birth and tested for IGRA at 44 weeks. Mtb (PPD, ESAT6/CFP10, Ag85A, LAM), HIV (GP120), and Influenza (HA) specific IgG, IgM, and IgA were measured in plasma samples using a bead based Luminex assay with Flexmap 3D. Results: In maternal plasma there were no differences in Mtb-specific antibodies or viral antibodies in relation to maternal IGRA status. ATB progressors showed increases in Mtb-specific antibodies at diagnosis compared to study entry. However, when compared to the non-progressors at entry, progressors had higher levels of Ag85A IgG and reduced ESAT6/CFP10 IgG and LAM IgG, IgM, and IgA1. All infants showed a decrease in IgG to viral antigens (HIV GP120 and HA) from 12 to 44 weeks attributed to waning of maternally transferred antibody titers. However, Mtb-specific (PPD, ESAT6/CFP10, Ag85A, and LAM) IgG and IgM increased from 12 to 44 weeks. HIV and HA IgG levels in maternal and 12-week infant plasma were highly correlated, and ESAT6/CFP10 IgG and LAM IgG showed a relationship between maternal and infant Abs. Finally, in the subset of infants that tested IGRA positive at 44 weeks, we observed a trend for lower LAM IgM compared to IGRA- infants at 44 weeks. Discussion: The results from our study raise the possibility that antibodies to LAM are associated with protection from progression to ATB and support further research into the development of humoral immunity against TB through infection or vaccination. [ABSTRACT FROM AUTHOR]

Since 2019, Coronavirus Disease 2019(COVID-19) has affected millions of people worldwide. Except for acute respiratory distress syndrome, dysgeusis is also a common symptom of COVID-19 that burdens patients for weeks or permanently. However, the mechanisms underlying taste dysfunctions remain unclear. Here, we performed complete autopsies of five patients who died of COVID-19. Integrated tongue samples, including numerous taste buds, salivary glands, vessels, and nerves were collected to map the pathology, distribution, cell tropism, and receptor distribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the tongue. Our results revealed that all patients had moderate lymphocyte infiltration around the salivary glands and in the lamina propria adjacent to the mucosa, and pyknosis in the epithelia of taste buds and salivary glands. This may be because the serous acini, salivary gland ducts, and taste buds are the primary sites of SARS-CoV-2 infection. Multicolor immunofluorescence showed that SARS-CoV-2 readily infects Keratin (KRT)7+ taste receptor cells in taste buds, secretory cells in serous acini, and inner epithelial cells in the ducts. The major receptors, angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine subtype 2 (TMPRSS2), were both abundantly expressed in these cells. Viral antigens and receptor were both rarely detected in vessels and nerves. This indicates that SARS-CoV-2 infection triggers pathological injury in the tongue, and that dysgeusis may be directly related to viral infection and cellular damage. [ABSTRACT FROM AUTHOR]

Animal hyperimmune sera containing specific protective antibodies against bacterial and viral antigens, snake and insect venoms have been used for more than 120 years. Currently, antitoxins against bacterial toxins (diphtheria, tetanus, botulism, etc.), viruses (rabies, Ebola, SARS-CoV-2, etc.), venoms of snakes (viper, gyurza, efa, cobra, etc.), spiders (black widow spider, red-backed spider, etc.), and scorpions have been developed and are successfully used. The review is devoted to modern technologies for producing antitoxins and immunoglobulin preparations, as well as the main areas of their application, such as the prevention or treatment of bacterial and viral diseases, bites of venomous snakes and spiders. The main stages of the production of antitoxins and immunoglobulin preparations are considered. An important step in the production of these drugs is the proteolytic digestion of native immunoglobulin molecules using enzymes to obtain F(ab')2-fragments and remove Fc-fragments, that leads to the elimination of undesirable interactions with Fc-receptors in tissue, which reduces the frequency of side effects. Today, antitoxins and immunoglobulin preparations are widely used in practical medicine. In addition to the application of well-known antitoxins, purification methods are being improved and new drugs are being developed to fight with actual threats such as antitoxin against COVID-19. [ABSTRACT FROM AUTHOR]

The Pfizer-BioNTech vaccine was one of the essential tools in curtailing the COVID-19 pandemic. Unlike conventional vaccines, this newly approved mRNA vaccine is taken up by cells, which leads to the synthesis of the specific viral Spike antigen. The vaccine was initially introduced for adults, and the immunological profile of adult recipients is well-characterized. The vaccine was approved for paediatric use much later after its efficacy and safety had been confirmed in children. However, the complete picture of how the paediatric immune system in children reacts to the vaccine is not well documented. Therefore, in order to better understand the immune response in children, we analysed the humoral response, immune cell count, and interferon signalling in paediatric vaccine recipients ranging between 5 and 17 years of age. Our findings suggest that the paediatric recipients elicit a robust humoral response that is sustained for at least three months. We also found that the vaccine triggered a transient lymphocytopenia similar to that observed during viral infection. Interestingly, we also found that the vaccine may sensitise the interferon signalling pathway, priming the cells to mount a potent response when exposed to interferons during a subsequent infection. The study offers new insights into the workings of the paediatric immune system and innate immunity, thereby opening the doors for further research in this field. [ABSTRACT FROM AUTHOR]

Immunoassays designed to detect SARS-CoV-2 protein antigens are now commercially available. The most widely used tests are rapid lateral flow assays that generate results in ~15 minutes for diagnosis at the point-of-care. Higher throughput, laboratory-based SARS-CoV-2 antigen (Ag) assays have also been developed. The overall accuracy of SARS-CoV-2 Ag tests, however, is not well defined. The Infectious Diseases Society of America (IDSA) convened an expert panel to perform a systematic review of the literature and develop best-practice guidance related to SARS-CoV-2 Ag testing. This guideline is the third in a series of rapid, frequently updated COVID-19 diagnostic guidelines developed by IDSA. IDSA's goal was to develop evidence-based recommendations or suggestions that assist clinicians, clinical laboratories, patients, public health authorities, administrators, and policymakers in decisions related to the optimal use of SARS-CoV-2 Ag tests in both medical and nonmedical settings. A multidisciplinary panel of infectious diseases clinicians, clinical microbiologists, and experts in systematic literature review identified and prioritized clinical questions related to the use of SARS-CoV-2 Ag tests. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make testing recommendations. The panel agreed on 5 diagnostic recommendations. These recommendations address Ag testing in symptomatic and asymptomatic individuals as well as assess single versus repeat testing strategies. Data on the clinical performance of US Food and Drug Administration SARS-CoV-2 Ag tests with Emergency Use Authorization are mostly limited to single, one-time testing versus standard nucleic acid amplification testing (NAAT) as the reference standard. Rapid Ag tests have high specificity and low to modest sensitivity compared with reference NAAT methods. Antigen test sensitivity is heavily dependent on viral load, with differences observed between symptomatic compared with asymptomatic individuals and the time of testing post-onset of symptoms. Based on these observations, rapid reverse transcriptase–polymerase chain reaction (RT-PCR) or laboratory-based NAAT remain the diagnostic methods of choice for diagnosing SARS-CoV-2 infection. However, when molecular testing is not readily available or is logistically infeasible, Ag testing can help identify some individuals with SARS-CoV-2 infection. The overall quality of available evidence supporting use of Ag testing was graded as very low to moderate. [ABSTRACT FROM AUTHOR]

Immunoassays designed to detect SARS-CoV-2 protein antigens (Ag) are commonly used to diagnose COVID-19. The most widely used tests are lateral flow assays that generate results in approximately 15 minutes for diagnosis at the point-of-care. Higher throughput, laboratory-based SARS-CoV-2 Ag assays have also been developed. The number of commercially available SARS-CoV-2 Ag detection tests has increased rapidly, as has the COVID-19 diagnostic literature. The Infectious Diseases Society of America (IDSA) convened an expert panel to perform a systematic review of the literature and develop best-practice guidance related to SARS-CoV-2 Ag testing. This guideline is an update to the third in a series of frequently updated COVID-19 diagnostic guidelines developed by the IDSA. IDSA's goal was to develop evidence-based recommendations or suggestions that assist clinicians, clinical laboratories, patients, public health authorities, administrators, and policymakers in decisions related to the optimal use of SARS-CoV-2 Ag tests in both medical and nonmedical settings. A multidisciplinary panel of infectious diseases clinicians, clinical microbiologists, and experts in systematic literature review identified and prioritized clinical questions related to the use of SARS-CoV-2 Ag tests. A review of relevant, peer-reviewed published literature was conducted through 1 April 2022. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was used to assess the certainty of evidence and make testing recommendations. The panel made 10 diagnostic recommendations that address Ag testing in symptomatic and asymptomatic individuals and assess single versus repeat testing strategies. US Food and Drug Administration (FDA) SARS-CoV-2 Ag tests with Emergency Use Authorization (EUA) have high specificity and low to moderate sensitivity compared with nucleic acid amplification testing (NAAT). Ag test sensitivity is dependent on the presence or absence of symptoms and, in symptomatic patients, on timing of testing after symptom onset. In most cases, positive Ag results can be acted upon without confirmation. Results of point-of-care testing are comparable to those of laboratory-based testing, and observed or unobserved self-collection of specimens for testing yields similar results. Modeling suggests that repeat Ag testing increases sensitivity compared with testing once, but no empirical data were available to inform this question. Based on these observations, rapid RT-PCR or laboratory-based NAAT remain the testing methods of choice for diagnosing SARS-CoV-2 infection. However, when timely molecular testing is not readily available or is logistically infeasible, Ag testing helps identify individuals with SARS-CoV-2 infection. Data were insufficient to make a recommendation about the utility of Ag testing to guide release of patients with COVID-19 from isolation. The overall quality of available evidence supporting use of Ag testing was graded as very low to moderate. [ABSTRACT FROM AUTHOR]

Background Persistent mortality in adults hospitalized due to acute COVID-19 justifies pursuit of disease mechanisms and potential therapies. The aim was to evaluate which virus and host response factors were associated with mortality risk among participants in Therapeutics for Inpatients with COVID-19 (TICO/ACTIV-3) trials. Methods A secondary analysis of 2625 adults hospitalized for acute SARS-CoV-2 infection randomized to 1 of 5 antiviral products or matched placebo in 114 centers on 4 continents. Uniform, site-level collection of participant baseline clinical variables was performed. Research laboratories assayed baseline upper respiratory swabs for SARS-CoV-2 viral RNA and plasma for anti–SARS-CoV-2 antibodies, SARS-CoV-2 nucleocapsid antigen (viral Ag), and interleukin-6 (IL-6). Associations between factors and time to mortality by 90 days were assessed using univariate and multivariable Cox proportional hazards models. Results Viral Ag ≥4500 ng/L (vs <200 ng/L; adjusted hazard ratio [aHR], 2.07; 1.29–3.34), viral RNA (<35 000 copies/mL [aHR, 2.42; 1.09–5.34], ≥35 000 copies/mL [aHR, 2.84; 1.29–6.28], vs below detection), respiratory support (<4 L O2 [aHR, 1.84; 1.06–3.22]; ≥4 L O2 [aHR, 4.41; 2.63–7.39], or noninvasive ventilation/high-flow nasal cannula [aHR, 11.30; 6.46–19.75] vs no oxygen), renal impairment (aHR, 1.77; 1.29–2.42), and IL-6 >5.8 ng/L (aHR, 2.54 [1.74–3.70] vs ≤5.8 ng/L) were significantly associated with mortality risk in final adjusted analyses. Viral Ag, viral RNA, and IL-6 were not measured in real-time. Conclusions Baseline virus-specific, clinical, and biological variables are strongly associated with mortality risk within 90 days, revealing potential pathogen and host-response therapeutic targets for acute COVID-19 disease. [ABSTRACT FROM AUTHOR]

Immune responses from prior severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 vaccination mitigate disease severity, but they do not fully prevent subsequent infections, especially from genetically divergent strains. We examined the incidence of and immune differences against human endemic coronaviruses (eCoVs) as a proxy for response against future genetically heterologous coronaviruses (CoVs). We assessed differences in symptomatic eCoV and non-CoV respiratory disease incidence among those with known prior SARS-CoV-2 infection or previous COVID-19 vaccination but no documented SARS-CoV-2 infection or neither exposure. Retrospective cohort analyses suggest that prior SARS-CoV-2 infection, but not previous COVID-19 vaccination alone, associates with a lower incidence of subsequent symptomatic eCoV infection. There was no difference in non-CoV incidence, implying that the observed difference was eCoV specific. In a second cohort where both cellular and humoral immunity were measured, those with prior SARS-CoV-2 spike protein exposure had lower eCoV-directed neutralizing antibodies, suggesting that neutralization is not responsible for the observed decreased eCoV disease. The three groups had similar cellular responses against the eCoV spike protein and nucleocapsid antigens. However, CD8+ T cell responses to the nonstructural eCoV proteins nsp12 and nsp13 were higher in individuals with previous SARS-CoV-2 infection as compared with the other groups. This association between prior SARS-CoV-2 infection and decreased incidence of eCoV disease may therefore be due to a boost in CD8+ T cell responses against eCoV nsp12 and nsp13, suggesting that incorporation of nonstructural viral antigens in a future pan-CoV vaccine may improve vaccine efficacy. Editor's summary: In addition to SARS-CoV-2 and other highly pathogenic coronaviruses, humans can be infected with a number of so-called endemic coronaviruses (eCoVs). These eCoVs, such as HCoV-OC43, are one of the causes of the common cold. Although there is similarity between SARS-CoV-2 and many eCoVs, the degree of cross-protection between the two has not been fully elucidated. Here, Bean et al. asked whether prior infection with or vaccination against SARS-CoV-2 protected against symptomatic eCoV infection. Unlike vaccination, prior infection was associated with fewer cases of symptomatic eCoV infection in a retrospective cohort. To identify the potential mediators of this protection, peripheral blood was obtained from a second cohort. The authors found that CD8+ T cell responses specifically targeting two nonstructural eCoV proteins, nsp12 and nsp13, were enriched only in those with prior infection. These data suggest that CD8+ T cell responses against conserved proteins may confer protection against a broad array of coronaviruses. —Courtney Malo [ABSTRACT FROM AUTHOR]

The cellular prion protein (PrPC) is an extracellular cell membrane protein. Due to its diversified roles, a definite role of PrPC has been difficult to establish. During viral infection, PrPC has been reported to play a pleiotropic role. Here, we have attempted to envision the function of PrPC in the neurotropic m-CoV-MHV-RSA59-induced model of neuroinflammation in C57BL/6 mice. A significant upregulation of PrPC at protein and mRNA levels was evident in infected mouse brains during the acute phase of neuroinflammation. Furthermore, investigation of the effect of MHV-RSA59 infection on PrPC expression in specific neuronal, microglial, and astrocytoma cell lines, revealed a differential expression of prion protein during neuroinflammation. Additionally, siRNA-mediated downregulation of prnp transcripts reduced the expression of viral antigen and viral infectivity in these cell lines. Cumulatively, our results suggest that PrPC expression significantly increases during acute MHV-RSA59 infection and that PrPC also assists in viral infectivity and viral replication. [ABSTRACT FROM AUTHOR]

Vaccinia virus is the most successful vaccine in human history and functions as a protective vaccine against smallpox and monkeypox, highlighting the importance of ongoing research into vaccinia due to its genetic similarity to other emergent poxviruses. Moreover, vaccinia's ability to accommodate large genetic insertions makes it promising for vaccine development and potential therapeutic applications, such as oncolytic agents. Thus, understanding how superior immunity is generated by vaccinia is crucial for designing other effective and safe vaccine strategies. During vaccinia inoculation by scarification, the skin serves as a primary site for the virus–host interaction, with various cell types playing distinct roles. During this process, hematopoietic cells undergo abortive infections, while non-hematopoietic cells support the full viral life cycle. This differential permissiveness to viral replication influences subsequent innate and adaptive immune responses. Dendritic cells (DCs), key immune sentinels in peripheral tissues such as skin, are pivotal in generating T cell memory during vaccinia immunization. DCs residing in the skin capture viral antigens and migrate to the draining lymph nodes (dLN), where they undergo maturation and present processed antigens to T cells. Notably, CD8+ T cells are particularly significant in viral clearance and the establishment of long-term protective immunity. Here, we will discuss vaccinia virus, its continued relevance to public health, and viral strategies permissive to immune escape. We will also discuss key events and populations leading to long-term protective immunity and remaining key gaps. [ABSTRACT FROM AUTHOR]

B2 haplotype major histocompatibility complex (MHC) has been extensively reported to confer resistance to various avian diseases. But its peptide-binding motif is unknown, and the presenting peptide is rarely identified. Here, we identified its peptide-binding motif (X-A/V/I/L/P/S/G-X-X-X-X-X-X-V/I/L) in vitro using Random Peptide Library-based MHC I LC-MS/MS analysis. To further clarify the structure basis of motif, we determined the crystal structure of the BF2∗02:01-PB2552-560 complex at 1.9 Å resolution. We found that BF2∗02:01 had a relatively wide antigen-binding groove, and the structural characterization of pockets was consistent with the characterization of peptide-binding motif. The wider features of the peptide-binding motif and increased number of peptides bound by BF2∗02:01 than BF2∗04:01 might resolve the puzzles for the presence of potential H9N2 resistance in B2 chickens. Afterward, we explored the H9N2 avian influenza virus (AIV)-induced cellular immune response in B2 haplotype chickens in vivo. We found that ratio of CD8+ T cell and kinetic expression of cytotoxicity genes including Granzyme K, interferon-γ, NK lysin, and poly-(ADP-ribose) polymerase in peripheral blood mononuclear cells were significantly increased in defending against H9N2 AIV infection. Especially, we selected 425 epitopes as candidate epitopes based on the peptide-binding motif and further identified four CD8+ T-cell epitopes on H9N2 AIV including NS198-106, PB2552-560, NP182-190, and NP455-463 via ELI-spot interferon-γ detections after stimulating memory lymphocytes with peptides. More importantly, these epitopes were found to be conserved in H7N9 AIV and H9N2 AIV. These findings provide direction for developing effective T cell epitope vaccines using well-conserved internal viral antigens in chickens. [ABSTRACT FROM AUTHOR]

Background: Occult hepatitis B infection (OBI) refers to the presence of hepatitis B virus (HBV) DNA in the serum or liver of individuals who tested negative for HBV surface antigen (HBsAg). This study aimed to determine seropositivity for antibodies against HBV core antigen (anti-HBc) and the frequency of OBI among the HBsAg non-reactive blood donors in Mashhad, northeastern Iran. Methods: In this cross-sectional study, serum samples of HBsAg-negative blood donors were examined for anti-HBc during June and August 2018. Anti-HBc-positive samples were tested for antibodies against HBsAg (anti-HBs), and those with negative results were classified as isolated anti-HBc cases. The presence of HBV DNA in the C, S, and X gene regions was assessed by a qualitative real-time polymerase chain reaction method in all HBsAg-negative samples. OBI subjects were detected by the presence of at least one HBV genomic region. Results: Of 540 HBsAg-negative donors, 29 (5.4%; 95% confidence interval: 3.6--7.6%) showed seroreactivity for anti-HBc, of whom 18 individuals were also seropositive for anti-HBs. All donors showed negative results for all three HBV genes regardless of their serum anti-HBc status. Conclusion: Based on our findings, we suggest routine screening of Iranian blood donation volunteers for serum anti-HBc and anti-HBs but not HBV DNA. [ABSTRACT FROM AUTHOR]

Introduction: Chronic hepatitis B (CHB) infection is accountable for nearly 240 million cases worldwide. Hepatitis B virus (HBV) has a propensity to show a divergent phase, and isolated measure of high HBV DNA level may not reflect the stage of the disease. In this background, this study was done to detect hepatitis B e antigen (HBeAg) and HBV DNA levels among hepatitis B surface antigen (HBsAg)-positive CHB cases and to determine the stage of disease with viral markers and biochemical parameters such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Materials and Methods: Blood samples were collected from 50 participants with CHB (HBsAg positive for more than 6 months) tested for HBe Ag by enzyme-linked immunosorbent assay, HBV DNA, ALT, and AST levels. Results: Among the 50 cases, 31 (62%) were HBeAg negative. Among these 31 HBeAg-negative groups, 16 (52%) had HBV DNA levels >2000 IU/mL. In these 16 patients, six had ALT >40IU/mL. Conclusion: HBsAg, HBeAg, ALT levels, and HBV DNA are important markers to determine the clinical stage of the disease. Since it is a chronic disease, patients need long-term follow-up. Further, emergence of viral mutants among vaccinated and those on lamivudine aggravates the existing problem. [ABSTRACT FROM AUTHOR]

Coxsackievirus B1 (CVB1), an enterovirus with multiple clinical presentations, has been associated with potential long‐term consequences, including hand, foot, and mouth disease (HFMD), in some patients. However, the related animal models, transmission dynamics, and long‐term tissue tropism of CVB1 have not been systematically characterized. In this study, we established a model of CVB1 respiratory infection in rhesus macaques and evaluated the clinical symptoms, viral load, and immune levels during the acute phase (0–14 days) and long‐term recovery phase (15–30 days). We also investigated the distribution, viral clearance, and pathology during the long‐term recovery period using 35 postmortem rhesus macaque tissue samples collected at 30 days postinfection (d.p.i.). The results showed that the infected rhesus macaques were susceptible to CVB1 and exhibited HFMD symptoms, viral clearance, altered cytokine levels, and the presence of neutralizing antibodies. Autopsy revealed positive viral loads in the heart, spleen, pancreas, soft palate, and olfactory bulb tissues. HE staining demonstrated pathological damage to the liver, spleen, lung, soft palate, and tracheal epithelium. At 30 d.p.i., viral antigens were detected in visceral, immune, respiratory, and muscle tissues but not in intestinal or neural tissues. Brain tissue examination revealed viral meningitis‐like changes, and CVB1 antigen expression was detected in occipital, pontine, cerebellar, and spinal cord tissues at 30 d.p.i. This study provides the first insights into CVB1 pathogenesis in a nonhuman primate model of HFMD and confirms that CVB1 exhibits tissue tropism following long‐term infection. [ABSTRACT FROM AUTHOR]

Introduction: Rapid identification of infected individuals through viral RNA or antigen detection followed by effective personal isolation is usually the most effective way to prevent the spread of a newly emerging virus. Large-scale detection involves mass specimen collection and transportation. For biosafety reasons, denaturing viral transport medium has been extensively used during the SARS-CoV-2 pandemic. However, the high concentrations of guanidinium isothiocyanate (GITC) in such media have raised issues around sufficient GITC supply and laboratory safety. Moreover, there is a lack of denaturing transport media compatible with SARS-CoV-2 RNA and antigen detection. Methods: Here, we tested whether supplementing media containing low concentrations of GITC with ammonium sulfate (AS) would affect the throatswab detection of SARS-CoV-2 or a viral inactivation assay targeting coronavirus and other enveloped and non-enveloped viruses. The effect of adding AS to the media on RNA stability and its compatibility with SARS-CoV-2 antigen detection were also tested. Results and discussion: We found that adding AS to the denaturing transport media reduced the need for high levels of GITC, improved SARS-COV-2 RNA detection without compromising virus inactivation, and enabled the denaturing transport media compatible with SARS-CoV-2 antigen detection. [ABSTRACT FROM AUTHOR]

Sensing of viral antigens has become a critical tool in combating infectious diseases. Current sensing techniques have a tradeoff between sensitivity and time of detection; with 10–30 min of detection time at a relatively low sensitivity and 6–12 h of detection at a high (picomolar) sensitivity. In this research, uniquely nanoengineered interfaces are demonstrated on 3D electrodes that enable the detection of spike antigens of SARS‐CoV‐2 and their variants in seconds at femtomolar concentrations with excellent specificity, thus, overcoming this tradeoff. The 3D electrodes, manufactured using a high‐resolution aerosol jet 3D nanoprinter, consist of a microelectrode array of sintered gold nanoparticles coated with graphene and antibodies specific to severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) spike antigens. An impedance‐based sensing modality is employed to sense several pseudoviruses of SARS‐CoV‐2 variants of concern (VOCs). This device is sensitive to most of the pseudoviruses of SARS‐CoV‐2 VOCs. A high sensitivity of 100 fm, along with a low limit‐of‐detection of 9.2 fm within a test range of 0.1–1000 pm, and a detection time of 43 s are shown. This work illustrates that effective nano‐bioengineering of interfaces can be used to create an ultrafast and ultrasensitive healthcare diagnostic tool for combating emerging infections. [ABSTRACT FROM AUTHOR]

High‐precision viral detection at point of need with clinical samples plays a pivotal role in the diagnosis of infectious diseases and the control of a global pandemic. However, the complexity of clinical samples that often contain very low viral concentrations makes it a huge challenge to develop simple diagnostic devices that do not require any sample processing and yet are capable of meeting performance metrics such as very high sensitivity and specificity. Herein we describe a new single‐pot and single‐step electrochemical method that uses real‐time kinetic profiling of the interaction between a high‐affinity aptamer and an antigen on a viral surface. This method generates many data points per sample, which when combined with machine learning, can deliver highly accurate test results in a short testing time. We demonstrate this concept using both SARS‐CoV‐2 and Influenza A viruses as model viruses with specifically engineered high‐affinity aptamers. Utilizing this technique to diagnose COVID‐19 with 37 real human saliva samples results in a sensitivity and specificity of both 100 % (27 true negatives and 10 true positives, with 0 false negative and 0 false positive), which showcases the superb diagnostic precision of this method. [ABSTRACT FROM AUTHOR]

Pharmacodynamic assessment of T-cell-based cancer immunotherapies often focus on detecting rare circulating T-cell populations. The therapy-induced immune cells in blood-derived clinical samples are often present in very low frequencies and with the currently available T-cell analytical assays, amplification of the cells of interest prior to analysis is often required. Current approaches aiming to enrich antigen-specific T cells from human Peripheral Blood Mononuclear Cells (PBMCs) depend on in vitro culturing in presence of their cognate peptides and cytokines. In the present work, we improved a standard, publicly available protocol for T-cell immune analyses based on the in vitro expansion of T cells. We used PBMCs from healthy subjects and well-described viral antigens as a model system for optimizing the experimental procedures and conditions. Using the standard protocol, we first demonstrated significant enrichment of antigen-specific T cells, even when their starting frequency ex vivo was low. Importantly, this amplification occurred with high specificity, with no or neglectable enrichment of irrelevant T-cell clones being observed in the cultures. Testing of modified culturing timelines suggested that the protocol can be adjusted accordingly to allow for greater cell yield with strong preservation of the functionality of antigen-specific T cells. Overall, our work has led to the refinement of a standard protocol for in vitro stimulation of antigen-specific T cells and highlighted its reliability and reproducibility. We envision that the optimized protocol could be applied for longitudinal monitoring of rare bloodcirculating T cells in scenarios with limited sample material. [ABSTRACT FROM AUTHOR]

Introduction: Modified Vaccinia Virus Ankara (MVA) is a safe vaccine vector inducing long- lasting and potent immune responses. MVA-mediated CD8+T cell responses are optimally induced, if both, direct- and cross-presentation of viral or recombinant antigens by dendritic cells are contributing. Methods: To improve the adaptive immune responses, we investigated the role of the purinergic receptor P2X7 (P2RX7) in MVA-infected feeder cells as a modulator of cross-presentation by non-infected dendritic cells. The infected feeder cells serve as source of antigen and provide signals that help to attract dendritic cells for antigen take up and to license these cells for cross-presentation. Results: We demonstrate that presence of an active P2RX7 in major histocompatibility complex (MHC) class I (MHCI) mismatched feeder cells significantly enhanced MVA-mediated antigen cross-presentation. This was partly regulated by P2RX7-specific processes, such as the increased availability of extracellular particles as well as the altered cellular energy metabolism by mitochondria in the feeder cells. Furthermore, functional P2RX7 in feeder cells resulted in a delayed but also prolonged antigen expression after infection. Discussion: We conclude that a combination of the above mentioned P2RX7-depending processes leads to significantly increased T cell activation via crosspresentation of MVA-derived antigens. To this day, P2RX7 has been mostly investigated in regards to neuroinflammatory diseases and cancer progression. However, we report for the first time the crucial role of P2RX7 for antigenspecific T cell immunity in a viral infection model. [ABSTRACT FROM AUTHOR]

The reemergence of the highly pathogenic avian influenza virus (HPAIV) subtype H5N1 in the United Kingdom in 2021–2022 has caused unprecedented epizootic events in wild birds and poultry. During the summer of 2022, there was a shift in virus transmission dynamics resulting in increased HPAIV infection in seabirds, and consequently, a profound impact on seabird populations. To understand the pathological impact of HPAIV in seabirds, we evaluated the virus antigen distribution and associated pathological changes in the tissues of great skua (Stercorarius skua, n = 8), long-tailed skua (Stercorarius longicaudus, n = 1), European herring gull (Larus argentatus, n = 5), and black-headed gull (Chroicocephalus ridibundus, n = 4), which succumbed to natural infection of HPAIV during the summer of 2022. Cases were collected from Shetland, including Scatness (mainland), No Ness (mainland), Clumlie (mainland), Hermaness (island), Fair Isle (island), Noss (island), and the West Midlands, South East, and South West of England. Grossly, gizzard ulceration was observed in one great skua and pancreatic necrosis was observed in 4 herring gulls, with intralesional viral antigen detected subsequently. Microscopical analysis revealed neuro-, pneumo-, lymphoid-, and cardiomyotropism of HPAIV H5N1, with the most common virus-associated pathological changes being pancreatic and splenic necrosis. Examination of the reproductive tract of the great skua revealed HPAIV-associated oophoritis and salpingitis, and virus replication within the oviductal epithelium. The emergence of HPAIV in seabirds Stercorariidae and Laridae, particularly during summer 2022, has challenged the dogma of HPAIV dynamics, posing a significant threat to wild bird life with potential implications for the reproductive performance of seabirds of conservation importance. [ABSTRACT FROM AUTHOR]

An epidemic of highly pathogenic avian influenza (HPAI) began in North America in the winter of 2021. The introduced Eurasian H5N1 clade 2.3.4.4b virus subsequently reassorted with North American avian influenza strains. This postmortem study describes the lesions and influenza A virus antigen distribution in 3 species of raptors, including bald eagles (Haliaeetus leucocephalus, n = 6), red-tailed hawks (Buteo jamaicensis, n = 9), and great horned owls (Bubo virginianus, n = 8), naturally infected with this virus strain based on positive reverse transcriptase polymerase chain reaction and sequencing results from oropharyngeal swabs. The birds presented with severe neurologic signs and either died or were euthanized because of the severity of their clinical signs and suspected influenza virus infection. Gross lesions were uncommon and included forebrain hemorrhages in 2 eagles, myocarditis in 1 hawk, and multifocal pancreatic necrosis in 3 owls. Histological lesions were common and included encephalitis, myocarditis, multifocal pancreas necrosis, multifocal adrenal necrosis, histiocytic splenitis, and anterior uveitis in decreasing frequency. Influenza A viral antigen was detected in brain, heart, pancreas, adrenal gland, kidney, spleen, liver, and eye. In conclusion, bald eagles, red-tailed hawks, and great horned owls infected with the HPAI clade 2.3.4.4b virus strain and showing neurological signs of illness may develop severe or fatal disease with histologically detectable lesions in the brain that are frequently positive for viral antigen. [ABSTRACT FROM AUTHOR]

The infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated not only with the development of acute disease but also with long-term symptoms or post-acute sequelae of SARS-CoV-2 (PASC). Multiple lines of evidence support that some viral antigens and RNA can persist for up to 15 months in multiple organs in the body, often after apparent clearance from the upper respiratory system, possibly leading to the persistence of symptoms. Activation of the immune system to viral antigens is observed for a prolonged time, providing indirect evidence of the persistence of viral elements after acute infection. In the gastrointestinal tract, the persistence of some antigens could stimulate the immune system, shaping the local microbiota with potential systemic effects. All of these interactions need to be investigated, taking into account predisposing factors, multiplicity of pathogenic mechanisms, and stratifying populations of vulnerable individuals, particularly women, children, and immunocompromised individuals, where SARS-CoV-2 may present additional challenges. [ABSTRACT FROM AUTHOR]

• The immune response to vaccination is moderately heritable in dogs. • Many SNPs of low to high effect contribute to vaccine-induced immune response. • Genes involving the spliceosome may play a role in vaccine-induced immune response. Both genetic and non-genetic factors contribute to individual variation in the immune response to vaccination. Understanding how genetic background influences variation in both magnitude and persistence of vaccine-induced immunity is vital for improving vaccine development and identifying possible causes of vaccine failure. Dogs provide a relevant biomedical model for investigating mammalian vaccine genetics; canine breed structure and long linkage disequilibrium simplify genetic studies in this species compared to humans. The objective of this study was to estimate the heritability of the antibody response to vaccination against viral and bacterial pathogens, and to identify genes driving variation of the immune response to vaccination in Beagles. Sixty puppies were immunized following a standard vaccination schedule with an attenuated combination vaccine containing antigens for canine adenovirus type 2, canine distemper virus, canine parainfluenza virus, canine parvovirus, and four strains of Leptospira bacteria. Serum antibody measurements for each viral and bacterial component were measured at multiple time points. Heritability estimations and GWAS were conducted using SNP genotypes at 279,902 markers together with serum antibody titer phenotypes. The heritability estimates were: (1) to Leptospira antigens, ranging from 0.178 to 0.628; and (2) to viral antigens, ranging from 0.199 to 0.588. There was not a significant difference between overall heritability of vaccine-induced immune response to Leptospira antigens compared to viral antigens. Genetic architecture indicates that SNPs of low to high effect contribute to immune response to vaccination. GWAS identified two genetic markers associated with vaccine-induced immune response phenotypes. Collectively, these findings indicate that genetic regulation of the immune response to vaccination is antigen-specific and influenced by multiple genes of small effect. [ABSTRACT FROM AUTHOR]

The development of media for cell culture is a major issue in the biopharmaceutical industry, for the production of therapeutics, immune-modulating molecules and protein antigens. Chemically defined media offer several advantages, as they are free of animal-derived components and guarantee high purity and a consistency in their composition. Microorganisms of the genus Leishmania represent a promising cellular platform for production of recombinant proteins, but their maintenance requires supplements of animal origin, such as hemin and fetal bovine serum. In the present study, three chemically defined media were assayed for culturing Leishmania tarentolae, using both a wild-type strain and a strain engineered to produce a viral antigen. Among the three media, Schneider's Drosophila Medium supplemented with Horseradish Peroxidase proved to be effective for the maintenance of L. tarentolae promastigotes, also allowing the heterologous protein production by the engineered strain. Finally, the engineered strain was maintained in culture up to the 12th week without antibiotic, revealing its capability to produce the recombinant protein in the absence of selective pressure. [ABSTRACT FROM AUTHOR]

Data on the course of viral infections revealed severe inflammation as a consequence of antiviral immune response. Despite extensive research, there are insufficient data on the role of innate immune cells in promoting inflammation mediated by immune complexes (IC) of viral antigens and their specific antibodies. Recently, we demonstrated that antigens of human polyomaviruses (PyVs) induce an inflammatory response in macrophages. Here, we investigated macrophage activation by IC. We used primary murine macrophages as a cell model, virus-like particles (VLPs) of PyV capsid protein as antigens, and a collection of murine monoclonal antibodies (mAbs) of IgG1, IgG2a, IgG2b subclasses. The inflammatory response was investigated by analysing inflammatory chemokines and activation of NLRP3 inflammasome. We observed a diverse pattern of chemokine secretion in macrophages treated with different IC compared to VLPs alone. To link IC properties with cell activation status, we characterised the IC by advanced optical and acoustic techniques. Ellipsometry provided precise real-time kinetics of mAb-antigen interactions, while quartz crystal microbalance measurements showed changes in conformation and viscoelastic properties during IC formation. These results revealed differences in mAb-antigen interaction and mAb binding parameters of the investigated IC. We found that IC-mediated cell activation depends more on IC characteristics, including mAb affinity, than on mAb affinity for the activating Fc receptor. IC formed by the highest affinity mAb showed a significant enhancement of inflammasome activation. This may explain the hyperinflammation related to viral infection and vaccination. Our findings demonstrate that IC promote the viral antigen-induced inflammatory response depending on antibody properties. [ABSTRACT FROM AUTHOR]

Chicken coccidiosis caused by Eimeria spp. can occur on almost all poultry farms, causing huge economic losses to the industry. Genetically manipulated Eimeria parasites as a vaccine vector to deliver viral antigens have been reported. In our preliminary study, transgenic E. acervulina expressing a VP2 gene (Ea-VP2) of the infectious bursal disease virus (IBDV) demonstrated partial protection against IBDV infection. To enhance immune responses, we aimed to increase the VP2 gene copy number in transgenic E. acervulina. In this study, we used a novel plasmid vector carrying a VP2 gene fused with three flag tags and a red fluorescent reporter gene (mCherry). The vector was introduced into Ea-VP2 sporozoites through nucleofection, leading to the generation of Ea-2VP2. Subsequent analysis revealed a notable escalation in the fluorescent rate, increasing from 0.11 to 95.1% following four consecutive passages facilitated by fluorescent-activated cell sorting. Verification via PCR, Western blot, and immunofluorescence confirmed the successful construction of the Ea-2VP2 population. Despite lower fecundity compared to wild-type E. acervulina, Ea-2VP2 maintained immunogenicity. Our research effectively created a transgenic E. acervulina strain transfected sequentially with two copies of the VP2 gene from IBDV. This modification resulted in an increased humoral immune response after primary immunization in chickens. Additionally, it demonstrated a degree of protection within the bursa against IBDV infection. Future studies will focus on further enhancing immune response levels. [ABSTRACT FROM AUTHOR]

In the context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, significant attention was given to pulmonary manifestations. However, cardiac involvement is increasingly recognized as a critical factor influencing the prognosis, leading to myocardial damage, heart failure, acute coronary syndromes, potentially lethal arrhythmic events, and sudden cardiac death. Despite these findings, there is a lack of studies detailing the necroscopic, macroscopic, and microscopic cardiac changes associated with SARS-CoV-2. This study aimed to investigate the presence of SARS-CoV-2 viral proteins in cardiac tissue using immunohistochemical techniques to assess viral tropism. The analysis of cardiac tissue samples from deceased subjects, in different stages of conservation, confirmed to be positive for SARS-CoV-2 via reverse transcriptase-polymerase chain reaction (RT-PCR), showed immunopositivity for the SARS-CoV-2-NP viral antigen in 33% of cases. Notably, the presence of leukocyte infiltrates sufficient for diagnosing lymphocytic myocarditis was not observed. The central proinflammatory cytokines involved in the pathogenetic mechanism of coronavirus disease 19 (COVID-19) were researched using the immunohistochemical method. A significant increase in cytokine expression was detected, indicating myocardial involvement and dysfunction during SARS-CoV-2 infection. These findings suggest that the immunohistochemical detection of SARS-CoV-2 viral antigens and inflammatory cytokine expression in cardiac tissue could be crucial for a proper forensic assessment of the cause of death, even in sudden cardiac death. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to investigate the prevalence and seasonal distribution of rotavirus and enteric adenovirus in patients with acute gastroenteritis. Methods: The results of 2960 patients admitted to Ankara Training and Research Hospital with gastroenteritis between March 2018 and August 2019 were investigated retrospectively. A chromatographic immunoassay (Rotavirus and Adenovirus Combo Rapid Test, General Diagnostica Inc., Rancho Cucamonga, CA, USA), detecting both viruses simultaneously, was used according to the manufacturer’s instructions. Results: Of the 2960 patients, 1286 (43.4%) were female, 1674 (56.6%) were male, and 2873 (97.7%) and 87 (2.3%) were under 18 years old and 18 years and older, respectively. The number of Turkish and refugee patients was 2590 (87.5%) and 370 (12.5%), respectively. Viral antigens of 281/2960 (9.5%) were positive for rotavirus, and 54/2960 (1.8%) were positive for adenovirus. Of the Turkish patients, 243/2590 (9.4%) were rotavirus positive, and 51/2590 (1.9%) were adenovirus positive. Among the refugee patients, 38/370 (10.3%) were rotavirus positive, and 3/370 (0.8%) were adenovirus positive. The highest prevalence of rotavirus and adenovirus, according to age groups, was determined at 12-36 months of age (25.3%) and 49-59 months of age (3.2%), respectively. The highest prevalence of rotavirus and adenovirus positivity was in spring (17.8%) and in autumn (2.9%), respectively. Conclusion: Rotavirus is the most common cause of gastroenteritis during infancy and childhood. Additionally, enteric adenovirus is an important cause of gastroenteritis during this period. Since these viral infections may have serious complications, rapid diagnosis is important, and detection of both viruses among various populations may be useful for epidemiological purposes. [ABSTRACT FROM AUTHOR]

Objective: Many factors influence patient flow through an ED, including streaming, treatment spaces and staff resources. This pilot study explored and compared real time patient flow using a single‐stream system versus varying configurations of possible two‐stream systems using computer simulation. Methods: Simulation modelling was used to assess the delay in treatment of a rapid‐antigen‐tested‐based, two‐stream model for patient flow through ED during the peak phase of the COVID pandemic. Results: Modelling two‐stream configuration for all patients (minimum time to be seen for both COVID‐positive and COVID‐negative patients) showed that in the case study ED, a two‐stream system and linked changes in bed configuration for managing the risks of infection can impact delays in treatment. Conclusions: Data‐driven modelling within specific clinical settings can inform the (in)efficiency of patient flow processes and help clinicians and managers make evidence‐based decisions about patient transition through EDs. This can assist with reconfiguration of ED patient streaming particularly during periods of unique need, such as the recent COVID‐19 pandemic. [ABSTRACT FROM AUTHOR]

The ability to selectively bind to antigenic peptides and secrete effector molecules can define rare and low-affinity populations of cells with therapeutic potential in emerging T cell receptor (TCR) immunotherapies. We leverage cavity-containing hydrogel microparticles, called nanovials, each coated with peptide-major histocompatibility complex (pMHC) monomers to isolate antigen-reactive T cells. T cells are captured and activated by pMHCs inducing the secretion of effector molecules including IFN-γ and granzyme B that are accumulated on nanovials, allowing sorting based on both binding and function. The TCRs of sorted cells on nanovials are sequenced, recovering paired αβ-chains using microfluidic emulsion-based single-cell sequencing. By labeling nanovials having different pMHCs with unique oligonucleotide-barcodes and secretions with oligo-barcoded detection antibodies, we could accurately link TCR sequences to specific targets and rank each TCR based on the corresponding cell's secretion level. Using the technique, we identified an expanded repertoire of functional TCRs targeting viral antigens with high specificity and found rare TCRs with activity against cancer-specific splicing-enhanced epitopes. [ABSTRACT FROM AUTHOR]

Simple Summary: The clinical course of classic Hodgkin lymphoma arising in immune deficiency/dysregulation (CHL-IDD) differs from that of CHL arising in immunocompetent cases and typically exhibits aggressive clinical behaviors. This study investigated the genetic aberration of 9p24.1 and protein expression of PD-L1 and also analyzed the clinicopathological association of these genetic lesions in CHL-IDD. Our findings showed that PD-L1 expression and 9p24.1 copy number alterations were observed in all patients analyzed in this study. Though it is recognized that an increase in 9p24.1 copy number alteration is associated with a more aggressive clinical course in immunocompetent CHL patients, we identified a subset of the 9p24.1 copy gain group, which had less 9p24.1 copy number alteration than the amplification group, exhibited more extensive extranodal lesions and had higher clinical stages in CHL-IDD cases. This finding speculates the presence of a genetically distinct subgroup within CHL-IDD patients, which may explain certain characteristic features. A subset of patients with rheumatoid arthritis receiving methotrexate develop immune deficiencies and dysregulation-associated lymphoproliferative disorders. Patients with these disorders often exhibit spontaneous regression after MTX withdrawal; however, chemotherapeutic intervention is frequently required in patients with classic Hodgkin lymphoma arising in immune deficiency/dysregulation. In this study, we examined PD-L1 expression levels and 9p24.1 copy number alterations in 27 patients with classic Hodgkin lymphoma arising from immune deficiency/dysregulation. All patients demonstrated PD-L1 protein expression and harbored 9p24.1 copy number alterations on the tumor cells. When comparing clinicopathological data and associations with 9p24.1 copy number features, the copy gain group showed a significantly higher incidence of extranodal lesions and clinical stages than the amplification group. Notably, all cases in the amplification group had latency type II, while 6/8 (75%) in the copy gain group had latency type II, and 2/8 (25%) had latency type I. Thus, a subset of the copy-gain group demonstrated more extensive extranodal lesions and higher clinical stages. This finding speculates the presence of a genetically distinct subgroup within the group of patients who develop immune deficiencies and dysregulation-associated lymphoproliferative disorders, which may explain certain characteristic features. [ABSTRACT FROM AUTHOR]

Purpose: To describe the clinical characteristics of refugees with HIV from Ukraine that seek continuation of medical care in Germany. Methods: Fourty‐six refugees with HIV that had left Ukraine between 24 February and 30 December 2022 were examined. Information on patients' history was obtained using a standardized questionnaire for clinical care. Interviews were conducted in Russian during their first clinical presentation. Results: Fourty‐six persons (41 females and 5 males) were included and their mean age was 39.6 (±8.4) years. The mean time since HIV diagnosis was 8.0 (median, IQR 7.15) years and 70.3% of participants currently received tenfofovir‐DF, lamividine and dolutegravir. Most refugees had an undetectable HIV viral load and their current mean CD4 T cell count was 702 (SD ± 289) per μL. Serology revealed previous hepatitis B infection in 50.4% without evidence for replication, with undetectable anti‐hepatitis B surface antigen in the remaining refugees. Antibodies against hepatitis C were present in 23 refugees (50%), but only 10 patients had been diagnosed with hepatitis C previously. Five refugees had undergone successful antiviral treatment for hepatitis C. Detectable HCV‐RNA was evident in nine patients (19.6%). Sixteen (38.6%) refugees had a positive tuberculosis (TB) interferon gamma release assay, and four were on TB treatment for previously diagnosed infection. One had been diagnosed with multidrug‐resistant (MDR) TB, two with pre‐extensively drug‐resistant (pre‐XDR) TB and two with XDR TB and were treated with combinations of second‐line and novel agents according to WHO guidelines. Conclusions: Based on this preliminary analysis of a not fully representative cohort, refugees with HIV from Ukraine were young, mostly healthy females highly adherent to antiretroviral therapy. The rate of transmittable co‐infections urges early diagnostic evaluation and treatment. [ABSTRACT FROM AUTHOR]

Background: The prevalence of chronic hepatitis B (CHB) in Aboriginal and Torres Strait Islander Australians in Far North Queensland (FNQ) is greater than twice that of the general Australian population. CHB is common in Torres Strait Islanders diagnosed with hepatocellular carcinoma (HCC) – and in Aboriginals with HCC living in the Northern Territory – however, Aboriginals diagnosed with HCC in FNQ very rarely have CHB. The explanation for this apparent disparity is uncertain. Aims: To determine the HBV genotypes in the FNQ Aboriginal and Torres Strait Islander population and their correlation with clinical phenotype. Methods: We determined the HBV genotype of Aboriginal and Torres Strait Islander Australians living with CHB in FNQ and correlated this with demographic and clinical findings. Results: 134/197 (68%) enrolled individuals had a sufficient viral load for genotyping. All 40 people with HBV/D genotype had Aboriginal heritage, whereas 85/93 (91%) with HBV/C had Torres Strait Islander heritage (P < 0.0001). Individuals with HBV/D were younger than those with HBV/C (median (interquartile range) age: 43 (39–48) vs 53 (42–66) years, P = 0.0002). However, they were less likely to be HBeAg positive (1/40 (3%) vs 23/93 (25%), P = 0.001). All three HCCs developed in Torres Strait Islanders; two‐thirds were infected with HBV/C14; genotyping was not possible in the other individual. All 10 diagnoses of cirrhosis occurred in Torres Strait Islanders, 6/10 were infected with HBV/C14, genotyping was not possible in the other four individuals. Conclusions: HBV genotypes in Aboriginal and Torres Strait Islander Australians in FNQ differ markedly, which could explain the significant differences in the clinical phenotype in the two populations and might be used to inform cost‐effective CHB care in the region. [ABSTRACT FROM AUTHOR]

Enveloped viruses pose a significant threat to human health, as evidenced by the recent COVID‐19 pandemic. Although current vaccine strategies have proven effective in preventing viral infections, the development of innovative vaccine technologies is crucial to fortify our defences against future pandemics. In this study, we introduce a novel platform called cell‐engineered virus‐mimetic nanovesicles (VNVs) and demonstrate their potential as a vaccine for targeting enveloped viruses. VNVs are generated by extruding plasma membrane‐derived blebs through nanoscale membrane filters. These VNVs closely resemble enveloped viruses and extracellular vesicles (EVs) in size and morphology, being densely packed with plasma membrane contents and devoid of materials from other membranous organelles. Due to these properties, VNVs express viral membrane antigens more extensively and homogeneously than EVs expressing the same antigen. In this study, we produced severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) VNVs expressing the SARS‐CoV‐2 Spike glycoprotein (S) on their surfaces and assessed their preclinical efficacy as a COVID‐19 vaccine in experimental animals. The administration of VNVs successfully stimulated the production of S‐specific antibodies both systemically and locally, and immune cells isolated from vaccinated mice displayed cytokine responses to S stimulation. [ABSTRACT FROM AUTHOR]

This article discusses the development of a new model of immune cells called Langerhans-like cells (LCs) for studying tick-borne encephalitis virus (TBEV) infection. LCs play a crucial role in the early-stage infection by transporting viral antigens from the skin to the lymph nodes. The researchers derived primary LCs from murine bone marrow and confirmed their suitability for TBEV infection experiments. The LCs were found to be susceptible to TBEV infection, with high cell viability and viral replication. This new model provides a valuable tool for studying TBEV infection and the dissemination of the virus. [Extracted from the article]

The long-lasting humoral immunity induced by viral infections or vaccinations depends on memory B cells with greatly increased affinity to viral antigens, which are evolved from germinal center (GC) responses. However, it is unclear whether antiviral memory B cells represent a distinct subset among the highly heterogeneous memory B cell population. Here, we examined memory B cells induced by a virus-mimicking antigen at both transcriptome and epigenetic levels and found unexpectedly that antiviral memory B cells exhibit an enhanced innate immune response, which appeared to be facilitated by the epigenetic memory that is established through the memory B cell development. In addition, T-bet is associated with the altered chromatin architecture and is required for the formation of the antiviral memory B cells. Thus, antiviral memory B cells are distinct from other GC-derived memory B cells in both physiological functions and epigenetic landmarks. [ABSTRACT FROM AUTHOR]

Merkel cell polyomavirus (MCPyV) is associated with Merkel cell carcinoma (MCC). In tumor cells the MCPyV large T antigen (LT-Ag) is frequently found truncated and this is considered a major tumor-specific signature. The role of MCPyV in other, non-MCC tumours, is little known. Viral DNA and/or tumour-specific mutations have been sometimes detected in different tumours, but such data are not unequivocal and the involvement of the virus in the tumorigenesis is not clear. In a previous study, we demonstrated a significantly higher prevalence of MCPyV DNA in formalin fixed paraffin embedded (FFPE) porocarcinoma tissues compared to the normal skin. In the present study, we investigated the presence of truncating mutations in MCPyV LT-Ag coding region in porocarcinoma specimens. Using several overlapped PCR primer pairs, the complete LT-Ag sequence from two biopsies were obtained. No truncating mutations were detected. The lack of truncating mutations in LT-Ag sequence does not seem to support the role of MCPyV in porocarcinoma oncogenesis. However, an oncogenetic mechanism, different from that proposed for MCC and not associated with the LT-Ag mutations/deletions, cannot be excluded. Further studies of more sequences coding for LT-Ag would be needed to verify this hypothesis. [ABSTRACT FROM AUTHOR]

Background: HBV infection can result in severe liver diseases and is one of the primary causes of liver cell carcinoma-related mortality. Liuwei Wuling tablet (LWWL) is a traditional Chinese medicine formula, with a protecting liver and decreasing enzyme activity, usually used to treat chronic hepatitis B with NAs in clinic. However, its main active ingredients and mechanism of action have not been fully investigated. Hence, we aimed to screen the active ingredient and effective ingredient combinations from Liuwei Wuling tablet to explore the anti-herpatitis B virus activity and mechanism. Methods: Analysis and screening of effective antiviral components in LWWL by network pharmacology, luteolin (Lut) may be a compound with significant antiviral activity. The mechanism of antiviral action of Lut was also found by real-time PCR detection and western blotting. Meanwhile, we established a co-culture model to investigate the antiviral mechanism of Schisandrin C (SC), one of the main active components of Schisandra chinensis fructus (the sovereign drug of LWWL). Next, HBV-infected mice were established by tail vein injection of pAAV-HBV1.2 plasmid and administered continuously for 20 days. And their antiviral capacity was evaluated by checking serum levels of HBsAg, HBeAg, levels of HBV DNA, and liver levels of HBcAg. Results: In this study, we conducted network pharmacology analysis on LWWL, and through in vitro experimental validation and data analysis, we found that luteolin (Lut) possessed obviously anti-HBV activity, inhibiting HBV replication by downregulating hepatocyte nuclear factor 4α (HNF4α) via the ERK pathway. Additionally, we established a co-culture system and proved that SC promoted activation of cGAS-STINIG pathway and IFN-β production in THP-1 cells to inhibit HBV replication in HepG2.2.15 cells. Moreover, we found the combination of SC and Lut shows a greater effect in inhibiting HBV compared to SC or Lut alone in HBV-infected mice. Conclusion: Taken together, our study suggests that combination of SC and Lut may be potential candidate drug for the prevention and treatment of chronic hepatitis B. [ABSTRACT FROM AUTHOR]

Background The fourth-generation (4th-gen) human immunodeficiency virus (HIV)-1/2 antibody/antigen (Ab/Ag) combination immunoassay currently used for HIV screening offers greater sensitivity than previous assays, but false-reactive results occur in up to 20% of patients. Large-scale observations in cancer patients are lacking. Methods We conducted a retrospective study of cancer patients seen at the University of Texas MD Anderson Cancer Center (March 2016–January 2023) who had reactive 4th-gen ARCHITECT HIV-1/2 Ab/Ag combination immunoassay results. We analyzed characteristics of patients with true-reactive and false-reactive results, defined based on Centers for Disease Control and Prevention criteria. Results A total of 43 637 patients underwent 4th-gen HIV screening, and 293 had reactive 4th-gen HIV test results. Twenty-one patients were excluded because they did not have cancer. Among the remaining 272 patients, 78 (29%) had false-reactive results. None of these patients experienced delays in their cancer treatment, but 26% experienced mental distress. Multivariate logistic regression analysis identified 5 predictors of having false-reactive results: age >60 years (adjusted odds ratio [aOR], 6.983; P <.0001), female sex (aOR, 6.060; P <.0001), race/ethnicity (Black: aOR, 0.274; Hispanic: aOR, 0.236; P =.002), syphilis coinfection (aOR, 0.046; P =.038), and plant alkaloids therapy (aOR, 2.870; P =.013). Conclusions False-reactive 4th-gen HIV test results occur in almost one-third of cancer patients. Physicians should be aware of the high rates of false-reactive HIV screening results in this patient population. These findings may have implications for counseling regarding testing, especially among those at low risk for HIV infection. [ABSTRACT FROM AUTHOR]

Infectious bronchitis virus (IBV) is a respiratory virus causing atropism in multiple body systems of chickens. Recently, the California 1737/04 (CA1737/04) IBV strain was identified as one of the circulating IBV variants among poultry operations in North America. Here, the pathogenicity and tissue tropism of CA1737/04 IBV strain in specific-pathogen-free (SPF) hens were characterized in comparison to Massachusetts (Mass) IBV. In 30 weeks-old SPF hens, Mass or CA1737/04 IBV infections were carried out, while the third group was maintained as a control group. Following infection, we evaluated clinical signs, egg production, viral shedding, serology, necropsy examination, and histopathology during a period of 19 days. Also, certain tissue affinity parameters were investigated, which involved the localization of viral antigens and the detection of viral RNA copies in designated tissues. Our findings indicate that infection with CA1737/04 or Mass IBV strain could induce significant clinical signs, reduced egg production, and anti-IBV antibodies locally in oviduct wash and systemically in serum. Both IBV strains showed detectable levels of viral RNA copies and induced pathology in respiratory, renal, enteric, and reproductive tissues. However, the CA1737/04 IBV strain had higher pathogenicity, higher tissue tropism, and higher replication in the kidney, large intestine, and different segments of the oviduct compared to the Mass IBV strain. Both IBV strains shed viral genome from the cloacal route, however, the Mass IBV infected hens shed higher IBV genome loads via the oropharyngeal route compared to CA1737/04 IBV-infected hens. Overall, the current findings could contribute to a better understanding of CA1737/04 IBV pathogenicity in laying hens. [ABSTRACT FROM AUTHOR]

Orf virus (ORFV) is a large DNA virus that can harbor and efficiently deliver viral antigens in swine. Here we used ORFV as a vector platform to deliver chimeric hemagglutinins (HA) of Influenza A virus of swine (IAV-S). Vaccine development against IAV-S faces limitations posed by strain-specific immunity and the antigenic diversity of the IAV-S strains circulating in the field. A promising alternative aiming at re-directing immune responses on conserved epitopes of the stalk segment of the hemagglutinin (HA2) has recently emerged. Sequential immunization with chimeric HAs comprising the same stalk but distinct exotic head domains can potentially induce cross-reactive immune responses against conserved epitopes of the HA2 while breaking the immunodominance of the head domain (HA1). Here, we generated two recombinant ORFVs expressing chimeric HAs encoding the stalk region of a contemporary H1N1 IAV-S strain and exotic heads derived from either H6 or H8 subtypes, ORFVD121cH6/1 and ORFVD121cH8/1, respectively. The resulting recombinant viruses were able to express the heterologous protein in vitro. Further, the immunogenicity and cross-protection of these vaccine candidates were assessed in swine after sequential intramuscular immunization with OV-cH6/1 and OV-cH8/1, and subsequent challenge with divergent IAV-S strains. Humoral responses showed that vaccinated piglets presented increasing IgG responses in sera. Additionally, cross-reactive IgG and IgA antibody responses elicited by immunization were detected in sera and bronchoalveolar lavage (BAL), respectively, by ELISA against different viral clades and a diverse range of contemporary H1N1 IAV-S strains, indicating induction of humoral and mucosal immunity in vaccinated animals. Importantly, viral shedding was reduced in nasal swabs from vaccinated piglets after intranasal challenge with either Oh07 (gamma clade) or Ca09 (npdm clade) IAV-S strains. These results demonstrated the efficiency of ORFV-based vectors in delivering chimeric IAV-S HA-based vaccine candidates and underline the potential use of chimeric-HAs for prevention and control of influenza in swine. [ABSTRACT FROM AUTHOR]