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Syncytium formation is one of major cytopathic effects of human immunodeficiency virus (HIV) infection, and requires the interaction of CD4 molecules on uninfected cells with HIV envelope glyoprotein gp120 expressed on HIV-infected cells. Recent evidence suggests chemokine receptors function as fusion cofactors. We have recently found that fusion regulatory protein (FRP)-1/ CD98 is involved in syncytium formation of HIV gp160-expressing U2ME-7 cells and TALL-1 cells persistently infected with HIV. However, resting lymphocytes were found to express no FRP-1 molecule. In this study, we demonstrated that recombinant gp120 (rpg120) has the ability to induce expression of FRP-1 on peripheral blood mononuclear cells (PBMC). Three-color flow cytometric analysis showed that rgp120-induced FRP-1 was expressed selectively on CD4+ T cells in a dose-dependent manner. FRP-1 expression level was maximum 3 days after addition of rgp120. Anti-CD4 and anti-gp120 antibodies blocked rgp120-induced FRP-1 expression. Co-cultivation of PBMC with HIV-1 gp160-expressing HeLa cells also resulted in the increased expression of FRP-1 on T cells. These results suggest that FRP-1 molecules are induced on CD4+ T cells via CD4-gp120 interaction and may play an important role in regulation of HIV-induced syncytium formation. [ABSTRACT FROM AUTHOR]

Membrane fusion is an important event in the functioning of a living organism. Life starts as a sperm fuses with the membrane of an egg, leading to its fertilization. Membrane fusion is also required for myogenesis, osteogenesis and placenta formation. Multinucleated giant cells originating from monocytes-macrophages are associated with granulomatous lesions formed in response to foreign bodies, viruses, and bacteria. The CD4 molecule acts as a receptor for HIV. The major virus envelope glycoprotein, gp120, attaches to CD4 molecules expressed on the host cell surface. After binding to CD4 on the target cells, HIV is internalized via direct, pH-independent fusion of the viral and cell membranes. However, attachment of HIV to CD4 on the target cells is not sufficient for fusion. Interaction of gp160-expressing cells with neighboring cells bearing surface CD4 molecules is also required for syncytium formation. Syncytium formation and subsequent generalized cell fusion have been reported as potentially important mechanisms of virus-induced cytotoxic effects. Some antibodies against CD98/FRP-1 suppressed virus-induced cell fusion and CD98-mediated cell fusion of monocytes, indicating that CD98/FRP-1 molecules are able to regulate cell fusion. In this study, the functional interaction between CD98 and CD147 was investigated. Three kinds (Ab1, 2, and 3) of anti-CD147 and three kinds of anti-CD98 antibodies were used. Ab1 suppressed CD98-mediated cell fusion, but showed no effect on cell aggregation of Cd+U2ME-7 cells, U937-2 cells expressing HIV gp160. On the other hand, Ab2 enhanced the CD98-mediated cell fusion. Ab1 showed suppressive effect at early stage and Ab2 showed enhancing effect at later stage. Ab2 and 3 suppressed the spontaneous cell agglutination and cell fusion of Cd+JME-2 cells, Jurkat cells expressing HIV gp160. Ab2 suppressed CD98-mediated cell fusion, but showed no effect on cell aggregation of Cd+JME-2 cells. Ab2 cancelled suppression of cell fusion induced by suppressive antibody against CD98. Ab2 and 3 also suppressed CD98-mediated cell fusion of monocytes. This study indicates the functional interaction between CD98 and CD147 in the regulation of cell fusion. [ABSTRACT FROM AUTHOR]

Human parainfluenza virus type 2 phosphoprotein (P) is an essential component of viral polymerase. The P gene encodes both P and accessory V proteins by a specific gene editing mechanism. Therefore, the N-terminal 164 amino acids of P protein are common to V protein. Interestingly, while P protein is located in the cytoplasm, V protein is found mainly in the nucleus. Using deletion mutants, we show the presence of a nuclear localization signal (NLS) in the P/V common domain, and a nuclear export signal (NES) in the C-terminal P specific region. The NLS region makes a complex with importin α5 or 7. In the presence of leptomycin B, P protein is retained in the nucleus, indicating that it contains a CRM1-dependent NES. We identified the NLS (65PVKPRRKK72) and the NES (225IIELLKGLDL234) using β-galactosidase fusion proteins. Moreover, nucleocytoplasmic shuttling of P protein appears to be important for efficient viral polymerase activity. [ABSTRACT FROM AUTHOR]

It has been reported that dual or multiple viruses can coinfect epithelial cells of the respiratory tract. However, little has been reported on in vitro interactions of coinfected viruses. To explore how coinfection of different viruses affects their biological property, we examined growth of influenza A virus (IAV) and human parainfluenza virus type 2 (hPIV2) during coinfection of Vero cells. We found that IAV growth was enhanced by coinfection with hPIV2. The enhanced growth of IAV was not reproduced by coinfection with an hPIV2 mutant with reduced cell fusion activity, or by ectopic expression of the V protein of hPIV2. In contrast, induction of cell fusion by ectopic expression of the hPIV2 HN and F proteins augments IAV growth. hPIV2 coinfection supported IAV growth in cells originated from the respiratory epithelium. The enhancement correlated closely with cell fusion ability of hPIV2 in those cells. These results indicate that cell fusion induced by hPIV2 infection is beneficial to IAV replication and that enhanced viral replication by coinfection with different viruses can modify their pathological consequences. [ABSTRACT FROM AUTHOR]

We have already reported the nucleotide sequences of the NP, P/V, M, F and HN genes of human parainfluenza virus type 4A (hPIV-4A) and type 4B (hPIV-4B). Here, we have determined the sequences of the L protein genes as well as the gene start, intergenic and end sequences, thereby completing the full-length genome sequence of hPIV-4A and 4B. hPIV-4A and 4B have 17,052 and 17,304 nucleotides, respectively. The end sequence of hPIV-4, especially 4B, was extraordinarily long. In a comparison with members of the genus Rubulavirus, the hPIV-4 L proteins were closely related to those of mumps virus (MUV) and hPIV-2, less closely related to those of Menangle virus and Tioman virus, and more distantly related to those of Mapuera virus and porcine rubulavirus. [ABSTRACT FROM AUTHOR]

We prepared the chimeric recombinant Sendai virus [rSeV(Ppi)] by replacing the P gene of the Z strain with that of pi strain for analyzing the function of Ppi, Vpi and Cpi proteins. Intriguingly, HA production by rSeV(Ppi) is significantly lower at 38°C than at 32°C, showing that virus growth of rSeV(Ppi) is slightly suppressed at 38°C. However, the main phenotypes of SeVpi, a marked temperature sensitivity as viral replication and an ability of establishing persistent infection, are not explained by the Ppi, Vpi and Cpi proteins. The V and C proteins form inclusion bodies in L929 cells infected with rSeV(Ppi) and incubated at 38°C. L929 cells infected with rSeV(Ppi) and L929 cells stably expressing the Cpi protein show resistance to interferon-β at 32 and 38°C, indicating that the Cpi protein per se is not temperature-sensitive to inhibition of IFN signaling. The complete genome sequences of Sendai virus (SeV) pi and parent Nagoya strains were determined. Fifty nucleic acid substitutions are found in the genome sequence of SeV pi strain in comparison with Nagoya strain. There are three nucleic acid substitutions in the leader sequence, while the trailer, intergenic, gene-end and gene-start sequences of both strains are completely identical. Deletions and insertions of nucleotide are not found. There are 32 amino acid substitutions in Sendai virus pi strain. The specific amino acid substitutions unique to the SeVpi are 18. Information about the complete genome sequences of SeVpi strain is important to totally understand the persistent infection and lower pathogenicity of SeV. [ABSTRACT FROM AUTHOR]

Ectopic protein with proper steric structure was efficiently loaded onto the envelope of the F gene-defective BC-PIV vector derived from human parainfluenza virus type 2 (hPIV2) by a reverse genetics method of recombinant virus production. Further, ectopic antigenic peptide was successfully loaded either outside, inside, or at both sides of the envelope of the vector. The BC-PIV vector harboring the Ebola virus GP gene was able to elicit neutralizing antibodies in mice. In addition, BC-PIV with antigenic epitopes of both melanoma gp100 and WT1 tumor antigen induced a CD8+ T-cell-mediated response in tumor-transplanted syngeneic mice. Considering the low pathogenicity and recurrent infections of parental hPIV2, BC-PIV can be used as a versatile vector with high safety for recombinant vaccine development, addressing unmet medical needs. [ABSTRACT FROM AUTHOR]

Influenza A virus (IAV) infection contributes to high annual morbidity and mortality, thus necessitating measures aimed at protecting against the disease. Alcohol-based disinfectants are commonly used to inactivate IAV, but they have several undesirable properties. In search of other means which would inactivate IAV, we focused on the effect of alkaline solutions on IAV. We found the viral infectivity remarkably decreased with treatment of an alkaline solution at pH 12.0 for 1 min, where destruction of the viral spikes was observed using an electron microscope. A more detailed examination revealed that the infectivity of IAV was remarkedly reduced by brief treatment with the alkaline solution at pH 11.75 or above, most likely due to the degradation of viral hemagglutinin protein. These results show that at a high pH, the haemagglutinin protein is degraded, resulting in very rapid inactivation of IAV.

The eight flavonoids, apigenin, chrysin, hesperidin, kaempferol, myricetin, quercetin, rutin and luteolin were tested for the inhibition of human parainfluenza virus type 2 (hPIV-2) replication. Three flavonoids out of the eight, kaempferol, quercetin and luteolin inhibited hPIV-2 replication. Kaempferol reduced the virus release (below 1/10,000), partly inhibited genome and mRNA syntheses, but protein synthesis was observed. It partly inhibited virus entry into the cells and virus spreading, and also partly disrupted microtubules and actin microfilaments, indicating that the virus release inhibition was partly caused by the disruption of cytoskeleton. Quercetine reduced the virus release (below 1/10,000), partly inhibited genome, mRNA and protein syntheses. It partly inhibited virus entry and spreading, and also partly destroyed microtubules and microfilaments. Luteolin reduced the virus release (below 1/100,000), largely inhibited genome, mRNA and protein syntheses. It inhibited virus entry and spreading. It disrupted microtubules and microfilaments. These results indicated that luteolin has the most inhibitory effect on hPIV-2 relication. In conclusion, the three flavonoids inhibited virus replication by the inhibition of genome, mRNA and protein syntheses, and in addition to those, by the disruption of cytoskeleton in vitro.

This study aimed to explore the factors influencing subjective health views based on the living conditions and concerns of university students during the coronavirus infection 2019 (COVID-19) pandemic. From March to April 2021, a questionnaire survey was administered to 8,547 Japanese university students, and logistic regression analysis was used to explore factors related to subjective health views. The results showed that satisfaction with quality of sleep (OR = 2.651, 95% Cl 2.370-2.966,p < 0.001), satisfaction with university life (OR = 2.486, 95%Cl 2.215-2.789, p < 0.001), satisfaction with diet (OR = 1.849, 95% CI: 1.496-2.285, p < 0.001), regular exercise (OR = 1.759, 95% CI: 1.594-1.941, p < 0.001), consciousness of nutritional balance (OR = 1.276, 95% CI: 1.147-1.420,p < 0.001), eating breakfast every day (OR = 1.247, 95% CI: 1.121-1.387, p < 0.001), and consuming soft drinks at least once a week (OR = 0.865, 95% CI: 0.755-0.966, p = 0.010) were positive factors for subjective views of health. On the other hand, anxiety about whether the necessary credits can be obtained (OR = 0.885, 95% CI: 0.799-0.980, p = 0.019), infection from minimal outings (OR = 0.881, 95% CI: 0.794-0.976, p = 0.016) building and maintaining friendships on campus (OR = 0.867, 95% CI: 0.767-0.980, p = 0.023), and being able to continue working (OR = 0.713, 95% CI: 0.640-0.795, p < 0.001) were identified as negative factors. To ensure a healthy university life during the COVID-19 pandemic or future pandemic, supports tailored to students' living conditions and measures to address their anxieties are required.

This study investigated nicotine dependence among Japanese university students who had reached the smoking age (20 years or older) by the time of the coronavirus disease 2019 (COVID-19) pandemic and examined factors that encourage early smoking cessation. Social dependence on nicotine was evaluated using the Kano Total Social Nicotine Dependence Level (KTSND), and physiological dependence was evaluated using the Fagerström Nicotine Dependence Index (FTND). Of the 356 college students who smoked (4.4% of the total), 182 (51.1%) stated that they were not interested in quitting. Furthermore, 124 (68.1%) of those with no interest in quitting smoking were aware that smoking is a high-risk factor for COVID-19, and 58 (31.9%) were unaware. The group not aware of this risk had significantly higher KTSND scores than the group aware of it. The examination of cigarette type that indicated the users of non-conventional cigarette products and dual-user groups scored significantly higher than the cigarette group on FTND items. Overall, the smokers scored above the normal range for social nicotine dependence, suggesting the need to reduce nicotine dependence to encourage college students who continue to smoke to quit smoking.

During the coronavirus disease 2019 (COVID-19) outbreak, firefighters have been working in an environment that is both physically and mentally taxing. This study aimed to investigate factors affecting health-related quality of life (HRQOL) among firefighters in Japan during the COVID-19 pandemic. A total of 227 firefighters from a single firefighting organization were surveyed in June 2021, during the fourth infection spread period of COVID-19 in Japan. Regression analysis was performed to examine factors affecting HRQOL of firefighters measured with the SF-8. In the present study, factors affecting HRQOL among firefighters during the COVID-19 pandemic were lack of sleep, physical abnormalities due to infection control measures, exercise habits, living with family members, and history of suspected COVID-19 infection. The present findings may help develop support services for first responders, including firefighters during the COVID-19 pandemic.

Saliva and salivary antimicrobial proteins play important roles in the innate immunity, which prevents infections of orally invading bacteria and viruses. In this study, we compared the secretion rates of salivary lactoferrin (Lac) and lysozyme (Lys) in heat-not-burn (HNB) cigarette smokers and non-smokers. The analysis population for this study included 212 members of the fire department, including 32 HNB cigarette smokers, 17 paper cigarette smokers, 14 combined HNB and paper cigarette smokers, and 149 non-smokers. Salivary Lac and Lys concentrations were assessed using enzyme immunoassay. Saliva secretion was significantly lower among HNB cigarette smokers (p < 0.01) than among non-smokers. Accompanying this result, salivary Lac and Lys secretion rates were significantly lower among smokers, particularly HNB cigarette smokers, than among non-smokers (all p < 0.01). Our findings suggest a possible adverse effect of HNB cigarette on the amount of Lac and Lys released into the oral cavity.

Since the novel coronavirus disease 2019 (COVID-19) pandemic, educational institutions have implemented measures such as school closures, raising concerns regarding the increase in psychological distress among university students. The purpose of this study is to identify factors that have influenced psychological distress among college freshmen during the COVID-19 pandemic. A questionnaire survey was conducted at the conclusion of the sixth wave of COVID-19 in Japan. Psychological distress was measured using the six-item Kessler Psychological Distress Scale (K6). Factors affecting psychological distress were calculated using regression analysis. Of the 2536 participants, 1841 (72.6%) reported having no psychological distress, while 695 (27.4%) reported having psychological distress. Factors that were identified to contribute to psychological distress were lack of sleep, weight gain or loss, worsening of interpersonal relationships, and physical symptoms and illnesses. A willingness to join an athletic club and having an environment in which it is easy to discuss worries and anxieties with others were factors that were identified to hinder psychological distress. It is necessary for universities to offer enhanced supports for physical and interpersonal activities. Additionally, it is imperative to encourage students to look after their physical health and to actively utilize university-based consultation systems.

The coronavirus disease 2019 (COVID-19) pandemic has decreased bystander cardiopulmonary resuscitation (BCPR) intervention rates. The purpose of this study was to elucidate the willingness of university freshmen to provide BCPR during the COVID-19 pandemic and the predictors thereof. A cross-sectional survey of 2789 newly enrolled university students was conducted after the end of the sixth wave of the COVID-19 epidemic in Japan; predictors of willingness to provide BCPR were assessed by regression analysis. Of the 2534 participants 1525 (60.2%) were willing to intervene and provide BCPR during the COVID-19 pandemic. Hesitancy due to the anxiety that CPR intervention might result in poor prognosis was a negative predictor of willingness. In contrast, anxiety about the possibility of infection during CPR intervention did not show a negative impact. On the other hand, interest in CPR and willingness to participate in a course, confidence in CPR skills, awareness of automated external defibrillation, and knowledge of CPR during the COVID-19 pandemic, were also positive predictors. This study suggests that the barrier to willingness to intervene with BCPR during a COVID-19 pandemic is not fear of infection, but rather hesitation due to the possibility of poor prognosis from the intervention. The significance of conducting this study during the COVID-19 epidemic is great, and there is an urgent need for measures to overcome hesitation regarding BCPR.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the coronavirus disease (COVID-19), is found primarily in the respiratory tract secretions of infected individuals with one of the main routes of transmission being direct or indirect contact. In this study, using fluorescent paint, we evaluated the spread of contaminants while playing catch with a baseball. Fluorescent paint was applied to the right hand of a right-handed baseball player who then engaged in playing catch with 10 other right-handed players (partners) for 5 min each. The fluorescent paint was detected on the right hands (inside) and gloves (inside) of all the 10 partners as well as on the ball; in some partners it was also detected on the back of the right hands or the back of the gloves. However, except for their right hands, fluorescent paint was not detected on the surface of the bodies of the partners. These observations indicated that the fluorescent paint (mimicking virus-containing contaminants) on the hand spreads very efficiently from person to person during the throwing and catching of a baseball, suggesting that a thorough and frequent disinfection of the hands and equipment is important in the prevention of infections that may occur while playing baseball.

School-based coronavirus disease 2019 (COVID-19) testing is an important part of a comprehensive prevention strategy in public health. To assess the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies in a university athletic club community with repeated occurrences of SARS-CoV-2 infections, we conducted a cross-sectional survey for asymptomatic antibody prevalence using a SARS-CoV-2 rapid antibody test kit. On January 26, 2021 we administered questionnaires to determine their history of contact with infected individuals and took blood samples from 129 undergraduates. The prevalence of SARS-CoV-2 antibodies among the subjects was 3.9%. Only 6.2% of the participants reported close contact with infected individuals. In this study, we clarified the prevalence of asymptomatic SARS-CoV-2 antibodies in university athletic clubs where SARS-CoV-2 infections had repeatedly occurred, which will be helpful in discussing how to identify and prevent the transmission of infections within university athletic club communities.

This study examined college students' perceptions of the association between smoking and novel coronavirus disease 2019 (COVID-19), changes in smoking behavior, and interest in quitting categorized by smoking device, to identify public health challenges. A questionnaire survey was conducted among 8,547 students in a Japanese university in March and April 2021. In response to "Awareness of the increased risk of COVID-19 infection due to smoking and the tendency to develop severe disease", current smokers (70.2%) were more aware of the risk than non-smokers (49.8%) (p < 0.001), with no significant difference according to smoking device (p = 0.213). "Interest in quitting smoking" (p = 0.323), and "Changes in smoking behavior during the COVID-19 pandemic" (p = 0.146) did not differ by smoking device. However, approximately 50% of the respondents answered that they were not interested in quitting smoking, while two-thirds reported that the number of cigarettes they smoked did not change during the pandemic. During the COVID-19 pandemic, college students were found to be less interested in quitting and not likely to change their smoking behavior, despite the knowledge of the increased risk of COVID-19 transmission and severity of disease from smoking, regardless of smoking device.

Smokers may have lower antibody titers after vaccination with a coronavirus disease 2019 (COVID-19) mRNA vaccine. However, to the best of our knowledge, no study has evaluated antibody titers after COVID-19 vaccination based on the level of smokers' cigarette dependence. In this study, we measured the level of serum anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) spike protein receptor-binding domain (S-RBD) immunoglobulin-G (IgG) by enzyme linked immunosorbent assay of 55 actively smoking Japanese social workers (firefighters, paramedics, and rescue workers) who had received two doses of the BNT162b2 vaccine. Further, we assessed their cigarette dependence using the Fagerstrom Test for Nicotine Dependence (FTND), measured their serum cotinine levels, and tested for their correlation with anti-RBD IgG levels. Serum anti-SARS-CoV-2 S-RBD protein IgG levels after BNT162b2 vaccination showed a significant negative correlation with FTND (ρ = -0.426, p = 0.001). In addition, serum cotinine level showed a significant positive correlation with FTND (ρ = 0.470, p = 0.000). However, no significant negative correlation was noted between serum cotinine and serum anti-SARS-CoV-2 S-RBD protein IgG levels (ρ = -0.156, p = 0.256). Our results suggest that smokers with strong cigarette dependence have inadequate anti-SARS-CoV-2 S-RBD protein IgG levels after COVID-19 mRNA vaccination.

The antiviral activities of eight nucleoside analog antiviral drugs (ribavirin, acyclovir, lamivudine, 3'-azido-3'-deoxythymidine, emtricitabine, tenofovir, penciclovir and ganciclovir) against human parainfluenza virus type 2 (hPIV-2) were investigated. Only ribavirin (RBV) inhibited both cell fusion and hemadsorption induced by hPIV-2. RBV considerably reduced the number of viruses released from the cells. Virus genome synthesis was inhibited by RBV, as determined by real time PCR. An indirect immunofluorescence study showed that RBV largely inhibited viral protein synthesis. mRNAs of the proteins were not detected, indicating that inhibition of protein synthesis was caused by transcription inhibition by RBV. Using a recombinant green fluorescence protein-expressing hPIV-2 without matrix protein, it was found that RBV did not completely inhibit virus entry into the cells; however, it almost completely blocked multinucleated giant cell formation. RBV did not disrupt actin microfilaments and microtubules. These results indicate that the inhibitory effect of RBV is caused by inhibition of both virus genome and mRNA synthesis, resulting in inhibition of virus protein synthesis, viral replication and multinucleated giant cell formation (extensive cell-to-cell spreading of the virus)., (© 2014 The Societies and Wiley Publishing Asia Pty Ltd.)

Our previous results have shown that some residues of V protein-specific domain in human parainfluenza virus type 2 (hPIV2) are essential not only for STAT protein degradation but also for promoting virus growth. Here, we demonstrated that the virus growth of these recombinant hPIV2s (rPIV2) expressing mutated V proteins were improved in HeLa cell transiently expressing the wild-type V protein, but not in the cells constitutively expressing it. Consequently, we identified the region of the V protein that is essential for its oligomerization and for complex formation with NP protein. We also identified a host protein, AlP1/Alix, involved in apoptosis and efficient budding of several enveloped viruses as an interacting partner of the V and NP proteins. Depletion of AIP1/Alix by small interfering RNA suppressed virus growth. These data suggest that the conserved carboxyl terminus of the V protein plays an important role in virus growth.

We have shown that the P and V proteins of human parainfluenza virus type 2 (hPIV-2) bind to genomic RNA by using Northwestern blot analysis. To identify the RNA-binding regions on the P and V proteins, we used a set of deletion mutants produced in Escherichia coli. One region required for the RNA-binding was found in the P-V common domain (aa 1-82). Others were found in the P protein-specific region (aa 249-354) and the V protein-specific region (aa 176-225). In addition, we have shown that substitutions of some basic residues with alanines in these regions abrogate RNA-binding by the P or V proteins. Intriguingly, the P and V proteins of hPIV2 can selectively bind to the viral RNA under our experimental conditions.