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Respiratory viral infection increases host susceptibility to secondary bacterial infections, yet the precise dynamics within airway epithelia remain elusive. Here, we elucidate the pivotal role of CD47 in the airway epithelium during bacterial super-infection. We demonstrated that upon influenza virus infection, CD47 expression was upregulated and localized on the apical surface of ciliated cells within primary human nasal or bronchial epithelial cells. This induced CD47 exposure provided attachment sites for Staphylococcus aureus, thereby compromising the epithelial barrier integrity. Through bacterial adhesion assays and in vitro pull-down assays, we identified fibronectin-binding proteins (FnBP) of S. aureus as a key component that binds to CD47. Furthermore, we found that ciliated cell-specific CD47 deficiency or neutralizing antibody-mediated CD47 inactivation enhanced in vivo survival rates. These findings suggest that interfering with the interaction between airway epithelial CD47 and pathogenic bacterial FnBP holds promise for alleviating the adverse effects of super-infection. During the influenza pandemic, a large number of deaths resulted from secondary bacterial pneumonia caused by common upper respiratory tract bacteria, such as Staphylococcus. Here, Moon et al, find that the interaction between airway epithelial CD47 and the pathogenic bacterial FnBP is critical in causing bacterial superinfection. [ABSTRACT FROM AUTHOR]

Influenza is a major cause of highly contagious respiratory illness resulting in high mortality and morbidity worldwide. Annual vaccination is an effective way to prevent infection and complication from constantly mutating influenza strains. Vaccination utilizes preemptive inoculation with live virus, live attenuated virus, inactivated virus, or virus segments for optimal immune activation. The route of administration also affects the efficacy of the vaccination. Here, we evaluated the effects of inoculation with ultraviolet (UV)-inactivated or live influenza A virus strains and compared their effectiveness and cross protection when intraperitoneal and intramuscular routes of administration were used in mice. Intramuscular or intraperitoneal inoculation with UV-inactivated Influenza A/WSN/1933 provided some protection against intranasal challenge with a lethal dose of live Influenza A/WSN/1933 but only when a high dose of the virus was used in the inoculation. By contrast, inoculation with a low dose of live virus via either route provided complete protection against the same intranasal challenge. Intraperitoneal inoculation with live or UV-inactivated Influenza A/Philippines/2/1982 and intramuscular inoculation with UV-inactivated Influenza A/Philippines/2/1982 failed to produce cross-reactive antibodies against Influenza A/WSN/1933. Intramuscular inoculation with live Influenza A/Philippines/2/1982 induced small amounts of cross-reactive antibodies but could not suppress the cytokine storm produced upon intranasal challenge with Influenza A/WSN/1993. None of the tested inoculation conditions provided observable cross protection against intranasal challenge with a different influenza strain. Taken together, vaccination efficacy was affected by the state and dose of the vaccine virus and the route of administration. These results provide practical data for the development of effective vaccines against influenza virus. [ABSTRACT FROM AUTHOR]

Due to the continuously mutating nature of the H3N2 virus, two aspects were considered when preparing the H3N2 microneedle vaccines: (1) rapid preparation and (2) cross-protection against multiple antigenic variants. Previous methods of measuring hemagglutinin (HA) content required the standard antibody, thus rapid preparation of H3N2 microneedle vaccines targeting the mutant H3N2 was delayed as a result of lacking a standard antibody. In this study, H3N2 microneedle vaccines were prepared by high performance liquid chromatography (HPLC) without the use of an antibody, and the cross-protection of the vaccines against several antigenic variants was observed. The HA content measured by HPLC was compared with that measured by ELISA to observe the accuracy of the HPLC analysis of HA content. The cross-protection afforded by the H3N2 microneedle vaccines was evaluated against several antigenic variants in mice. Microneedle vaccines for the 2019–20 seasonal H3N2 influenza virus (19–20 A/KS/17) were prepared using a dip-coating process. The cross-protection of 19–20 A/KS/17 H3N2 microneedle vaccines against the 2015–16 seasonal H3N2 influenza virus in mice was investigated by monitoring body weight changes and survival rate. The neutralizing antibody against several H3N2 antigenic variants was evaluated using the plaque reduction neutralization test (PRNT). HA content in the solid microneedle vaccine formulation with trehalose post-exposure at 40℃ for 24 h was 48% and 43% from the initial HA content by HPLC and ELISA, respectively. The vaccine was administered to two groups of mice, one by microneedles and the other by intramuscular injection (IM). In vivo efficacies in the two groups were found to be similar, and cross-protection efficacy was also similar in both groups. HPLC exhibited good diagnostic performance with H3N2 microneedle vaccines and good agreement with ELISA. The H3N2 microneedle vaccines elicited a cross-protective immune response against the H3N2 antigenic variants. Here, we propose the use of HPLC for a more rapid approach in preparing H3N2 microneedle vaccines targeting H3N2 virus variants. [ABSTRACT FROM AUTHOR]

Department of BioNano Technology, Gachon University, Seongnam, Republic of Korea The original Article has been corrected. Correction to: I Scientific Reports i https://doi.org/10.1038/s41598-022-16365-2, published online 16 July 2022 In the original version of this Article, Jung-Hwan Park was incorrectly affiliated with 'QuadMedicine R&D Centre, QuadMedicine Co., Ltd, Seongnam, Republic of Korea'. [Extracted from the article]

Multiple vaccines can be mixed into a single combination to be a single product. However, combination vaccines have problems of complexity. In this study, microneedles were utilized in a compartmental microneedle array (CMA) to deliver two influenza vaccine strains without mixing. In this study, the CMA had two compartments, and two rectangular structures were attached to each end of the array to enable integration of the compartments with the coating equipment. The coating solution, which contained influenza vaccines for B/Yamagata (B-Y) and B/Victoria (B-V), was filled into the two reservoirs of the container. The CMA was aligned with the container for dipping the first compartment of the array into the first reservoir and the second compartment into the second reservoir. The CMA containing B-Y and B-V separately was administered to mice, and weight change and survival were compared with other groups of mice administered (a) combination vaccines with microneedles, (b) two monovalent vaccines with microneedles, (c) intramuscularly with a combination vaccine, and (d) intramuscularly with two monovalent vaccines. Plaque reduction neutralization tests were also performed to compare the CMA group with the other groups. The CMA showed a relative standard error of less than 7% between samples in dose uniformity. It also showed comparable antibody-forming efficacy compared to other groups, especially by B/Yamagata virus challenge. The CMA mice group showed better survival and weight change than mice that received intramuscular (IM) injection of the combination vaccine. In the neutralizing antibody experiment, all microneedle groups showed a higher neutralizing antibody than the IM groups. Vaccines were administered without mixing by a single administration using a CMA, and the CMA showed comparable efficacy with IM administration of the combination vaccine. Multivalent vaccines can be delivered without mixing as a single product by using a CMA. Unlabelled Image • Compartmental microneedle array delivered bivalent antigens of B/Yamagata and B/Victoria as a single product by single administration. • Multivalent vaccines and multi-drugs can deliver drugs intradermally without mixing antigens and active pharmaceutical ingredients. [ABSTRACT FROM AUTHOR]

(1) Plaque reduction neutralization test (PRNT) for virus neutralization. IM (H1N1): intramuscular administration, RT-MN-T: room-temperature H1N1 microneedles with stabilizer, LT-MN-T: low-temperature H1N1 microneedles with stabilizer, LT-MN: low-temperature H1N1 microneedles without stabilizer. (2) The IM administration group had a lower neutralizing antibody than the microneedle group. (3) The microneedle group prepared at low temperature showed a similar antibody titer regardless of the addition of a stabilizer. (4) When the whole microneedle production process is performed at a low temperature, the influence of the stabilizer and the denaturation of the antigen can both be minimized, and as a result, immunogenicity can be induced effectively. During the manufacture of H1N1 microneedles, a stabilizer is usually added to maintain the antigenicity of the vaccine. However, finding a suitable stabilizer is difficult, and the addition of a stabilizer can limit the antigen dose and the addition of an adjuvant because of the limited volume of the microneedles. In this study, the authors evaluated whether H1N1 microneedles could be fabricated without a stabilizer by keeping the production environment at a low temperature. H1N1 microneedle patches without a stabilizer were prepared in a process that involved maintaining a low temperature of 10 °C. The protective immune response to this method of drug application was investigated by comparing it with traditional intramuscular (IM) immunization and with the use of H1N1 microneedles with a stabilizer. A process-sensitive antigen, H1N1, was stabilized without the use of a stabilizer in a process that maintained a low temperature of 10 °C. The preparation process consisted of coating and drying processes. In animal experiments, mice were immunized using an array of low-temperature H1N1 microneedles without a stabilizer (LT-MN), and they showed strong antibody responses. Compared to three other application methods of traditional IM immunization, low-temperature H1N1 microneedles with a stabilizer (LT-MN-T), and room-temperature H1N1 microneedles with a stabilizer (RT-MN-T), LT-MN produced comparable results in inducing protective immunity. A plaque reduction neutralization test found that LT-MN and LT-MN-T provided greater immunity compared with IM and RT-MN-T. A process in which the temperature is maintained at 10 °C can provide successful vaccination with H1N1 microneedles without the addition of a stabilizer. This process can be applied to various temperature-sensitive biologics. [ABSTRACT FROM AUTHOR]

Both antibodies and T cells contribute to immunity against influenza virus infection. However, the generation of strong Th1 immunity is crucial for viral clearance. Interestingly, we found that human dendritic cells (DCs) infected with influenza A virus have lower allospecific Th1-cell stimulatory abilities than DCs activated by other stimuli, such as lipopolysaccharide and Newcastle disease virus infection. This weak stimulatory activity correlates with a suboptimal maturation of the DCs following infection with influenza A virus. We next investigated whether the influenza A virus NS1 protein could be responsible for the low levels of DC maturation after influenza virus infection. The NS1 protein is an important virulence factor associated with the suppression of innate immunity via the inhibition of type I interferon (IFN) production in infected cells. Using recombinant influenza and Newcastle disease viruses, with or without the NS1 gene from influenza virus, we found that the induction of a genetic program underlying DC maturation, migration, and T-cell stimulatory activity is specifically suppressed by the expression of the NS1 protein. Among the genes affected by NS1 are those coding for macrophage inflammatory protein 1β, interleukin-12 p35 (IL-12 p35), IL-23 p19, RANTES, IL-8, IFN-α/β, and CCR7. These results indicate that the influenza A virus NS1 protein is a bifunctional viral immunosuppressor which inhibits innate immunity by preventing type I IFN release and inhibits adaptive immunity by attenuating human DC maturation and the capacity of DCs to induce T-cell responses. Our observations also support the potential use of NS1 mutant influenza viruses as live attenuated influenza virus vaccines. [ABSTRACT FROM AUTHOR]