Epitopes of an antibody that neutralizes a wide range of SARS-CoV-2 variants in a conserved subdomain 1 of the spike protein.

The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continued, enabling the virus to escape from host immunity by changing its spike antigen, while biased toward the receptor-binding domain and N-terminal domain. Here, we isolated a novel pan-SARS-CoV-2 neutralizing antibody (which we named MO11) for even the recent dominators XBB.1.16 and EG.5.1, from a convalescent patient who had received three doses of an original mRNA COVID-19 vaccination. A cryo-electron microscopy analysis of the spike-MO11 complex at 2.3 Å atomic resolution revealed that it recognizes a conserved epitope hidden behind a glycan shield at N331 on subdomain 1 (SD1), holding both the N- and C-terminal segments comprising SD1. Our identification of MO11 unveiled the functional importance of SD1 for the spike's function, and we discuss the potential availability of a novel common epitope among the SARS-CoV-2 variants.IMPORTANCENovel severe acute respiratory syndrome coronavirus 2 variants with immune evasion ability are still repeatedly emerging, nonetheless, a part of immunity developed in responding to the antigen of earlier variants retains efficacy against recent variants irrespective of the numerous mutations. In exploration for the broadly effective antibodies, we identified a cross-neutralizing antibody, named MO11, from the B cells of the convalescent patient. MO11 targets a novel epitope in subdomain 1 (SD1) and was effective against all emerging variants including XBB.1.16 and EG.5.1. The neutralizing activity covering from D614G to EG.5.1 variants was explained by the conservation of the epitope, and it revealed the importance of the subdomain on regulating the function of the antigen for viral infection. Demonstrated identification of the neutralizing antibody that recognizes a conserved epitope implies basal contribution of such group of antibodies for prophylaxis against COVID-19.

Seroprevalence of SARS-CoV-2 anti-spike IgG antibody among COVID-19 vaccinated individuals residing in Surabaya, East Java, Indonesia.

Background: To limit the SARS-CoV-2 transmission, the Indonesian government launched a COVID-19 vaccination program in January 2021. Studies on the clinical treatment and implementation of COVID-19 vaccination have shown promising results; however, it is necessary to estimate the effectiveness of the vaccines. With the ongoing COVID-19 pandemic, studies have highlighted the impact of COVID-19 vaccines, especially CoronaVac, on Indonesian healthcare workers. To get a better picture of how the vaccines work in Indonesia, it is necessary to estimate the prevalence of SARS-CoV-2 anti-S IgG antibody induced by the COVID-19 vaccine in individuals who have already received two-to-three doses of vaccines. Materials and Methods: Four-hundred and ninety-six whole-blood samples were collected from participants residing in Surabaya, East Java, Indonesia, who received a minimum of a two-dose COVID-19 vaccine. Serums were then isolated from the blood and subjected to detect SARS-CoV-2 anti-S IgG antibodies using a lateral flow immunochromatographic assay. Results: The prevalence of positive anti-S-IgG antibodies was 91.7% (455/496) in all participants receiving a minimum of a two-dose COVID-19 vaccine. As many as 209 (85.3%) and 141 (96.6%) participants were seropositive for receiving CoronaVac and AstraZeneca, respectively. Meanwhile, all participants receiving two-dose CoronaVac with one booster dose of Moderna (105/100%) were seropositive (p < 0.05). Age, comorbidity, and time after the last vaccine were significantly correlated with seropositivity (p < 0.05). Conclusion: Different vaccines might produce different antibody responses. Adopting a stronger policy regarding the administration of booster doses might be beneficial to elicit positive anti-S-IgG antibodies, especially among older individuals, those with comorbid diseases, and those with a longer time after the second vaccination dose.

SARS-CoV-2 lineages circulating during the first wave of the pandemic in North Sumatra, Indonesia.

Objectives: To determine the lineage distribution of the virus during the first wave of the pandemic in North Sumatra, Indonesia. Methods: A total of 20 samples with positive results based on reverse transcription-polymerase chain reaction were selected for virus culture and then performed whole-genome sequence analysis using next-generation sequencing which was applied by the Illumina MiSeq instrument. Results: Whole-genome sequence analysis revealed that the majority of our samples belong to lineages B.1.468 (n = 10), B.1 (n = 5), B.1.1 (n = 2), B.1.1.398 (n = 2), and B.6 (n = 1). Other unique amino acid mutations found in our samples were present in A58T on non-structural protein (NSP3) (70%), P323L on NSP12 (95%), Q57H on NS3 protein (75%), and D614G on S (100%). Conclusion: The SARS-CoV-2 lineage B.1.468 may be the main virus variant circulating in North Sumatra at the beginning of the emergence of COVID-19 cases in this province.

Human herpesvirus 6A nuclear matrix protein U37 interacts with heat shock transcription factor 1 and activates the heat shock response.

Nascent nucleocapsids of herpesviruses acquire a primary envelope during their nuclear export by budding through the inner nuclear membrane into the perinuclear space between the inner and outer nuclear membranes. This process is mediated by a conserved viral heterodimeric complex designated the nuclear egress complex, which consists of the nuclear matrix protein and the nuclear membrane protein. In addition to its essential roles during nuclear egress, the nuclear matrix protein has been shown to interact with intracellular signaling pathway molecules including NF-κB and IFN-ß to affect viral or cellular gene expression. The human herpesvirus 6A (HHV-6A) U37 gene encodes a nuclear matrix protein, the role of which has not been analyzed. Here, we show that HHV-6A U37 activates the heat shock element promoter and induces the accumulation of the molecular chaperone Hsp90. Mechanistically, HHV-6A U37 interacts with heat shock transcription factor 1 (HSF1) and induces its phosphorylation at Ser-326. We report that pharmacological inhibition of HSF1, Hsp70, or Hsp90 decreases viral protein accumulation and viral replication. Taken together, our results lead us to propose a model in which HHV-6A U37 activates the heat shock response to support viral gene expression and replication. IMPORTANCE Human herpesvirus 6A (HHV-6A) is a dsDNA virus belonging to the Roseolovirus genus within the Betaherpesvirinae subfamily. It is frequently found in patients with neuroinflammatory disease, although its pathogenetic role, if any, awaits elucidation. The heat shock response is important for cell survival under stressful conditions that disrupt homeostasis. Our results indicate that HHV-6A U37 activates the heat shock element promoter and leads to the accumulation of heat shock proteins. Next, we show that the heat shock response is important for viral replication. Overall, our findings provide new insights into the function of HHV-6A U37 in host cell signaling and identify potential cellular targets involved in HHV-6A pathogenesis and replication.

Risk of herpes zoster according to past history in the general population: The Japanese Shozu herpes zoster study.

Immunity is known to persist after vaccination for varicella zoster virus, but the duration of immunity in patients who develop herpes zoster (HZ) remains unknown. To investigate the association between a past history of HZ and its occurrence in the general population. The Shozu HZ (SHEZ) cohort study included data for 12 299 individuals aged ≥50 years with information on their HZ history. Cross-sectional and 3-year follow-up studies were carried out to analyze the associations between a history of HZ (yes <10 years, yes ≥10 years, no) and the proportion of positive varicella zoster virus skin test results (erythema diameter ≥5 mm) and the risk of HZ after adjusting for potential confounding factors including age, sex, body mass index, smoking status, sleep duration, and mental stress. The incidences of positive skin test results were 87.7% (470/536) for individuals with a history of HZ <10 years ago, 82.2% (396/482) for those with a history of HZ ≥10 years, and 80.2% (3614/4509) for those with no history of HZ. The multivariable odds ratios (95% confidence intervals) of erythema diameter ≥5 mm were 2.07 (1.57-2.73) and 1. 39 (1.08-1.80) for individuals with a history <10 years and ≥10 years ago, respectively, compared with no history. The corresponding multivariable hazard ratios of HZ were 0.54 (0.34-0.85) and 1.16 (0.83-1.61), respectively. A past history of HZ <10 years ago may reduce the occurrence of HZ.

Identification and Analysis of Monoclonal Antibodies with Neutralizing Activity against Diverse SARS-CoV-2 Variants.

We identified neutralizing monoclonal antibodies against severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) variants (including Omicron variants BA.5 and BA.2.75) from individuals who received two doses of mRNA vaccination after they had been infected with the D614G virus. We named them MO1, MO2, and MO3. Among them, MO1 showed particularly high neutralizing activity against authentic variants: D614G, Delta, BA.1, BA.1.1, BA.2, BA.2.75, and BA.5. Furthermore, MO1 suppressed BA.5 infection in hamsters. A structural analysis revealed that MO1 binds to the conserved epitope of seven variants, including Omicron variants BA.5 and BA.2.75, in the receptor-binding domain of the spike protein. MO1 targets an epitope conserved among Omicron variants BA.1, BA.2, and BA.5 in a unique binding mode. Our findings confirm that D614G-derived vaccination can induce neutralizing antibodies that recognize the epitopes conserved among the SARS-CoV-2 variants. IMPORTANCE Omicron variants of SARS-CoV-2 acquired escape ability from host immunity and authorized antibody therapeutics and thereby have been spreading worldwide. We reported that patients infected with an early SARS-CoV-2 variant, D614G, and who received subsequent two-dose mRNA vaccination have high neutralizing antibody titer against Omicron lineages. It was speculated that the patients have neutralizing antibodies broadly effective against SARS-CoV-2 variants by targeting common epitopes. Here, we explored human monoclonal antibodies from B cells of the patients. One of the monoclonal antibodies, named MO1, showed high potency against broad SARS-CoV-2 variants including BA.2.75 and BA.5 variants. The results prove that monoclonal antibodies that have common neutralizing epitopes among several Omicrons were produced in patients infected with D614G and who received mRNA vaccination.

Fourth mRNA vaccination increases cross-neutralizing antibody titers against SARS-CoV-2 variants, including BQ.1.1 and XBB, in a very elderly population.

BACKGROUND: Omicron variants with immune evasion have emerged, and they continue to mutate rapidly, raising concerns about the weakening of vaccine efficacy, and the very elderly populations are vulnerable to Coronavirus Disease 2019 (COVID-19). Therefore, to investigate the effect of multiple doses of mRNA vaccine for the newly emerged variants on these populations, cross-neutralizing antibody titers were examined against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variants, including BQ.1.1 and XBB. METHODS: Blood samples were taken from residents at four long-term care facilities in Hyogo prefecture, Japan (median age, 91 years), after 3rd (n = 67) and 4th (n = 48) mRNA vaccinations, from April to October 2022. A live virus microneutralization assay was performed to determine the neutralizing antibody titers in participants' sera. RESULTS: After 3rd vaccination, cross-neutralizing antibody prevalence against conventional (D614G) virus, Delta, Omicron BA.2, BA.5, BA.2.75, BQ.1.1, and XBB were 100%, 97%, 81%, 51%, 67%, 4%, and 21%, respectively. After 4th vaccination, the antibody positivity rates increased to 100%, 100%, 98%, 79%, 92%, 31%, and 52%, respectively. The 4th vaccination significantly increased cross-neutralizing antibody titers against all tested variants. CONCLUSION: The positivity rates for BQ.1.1 and XBB increased after 4th vaccination, although the titer value was lower than those of BA.5 and BA.2.75. Considering the rapid mutation of viruses and the efficacy of vaccines, it may be necessary to create a system that can develop vaccines suitable for each epidemic in consideration of the epidemic of the virus.

Predictors of herpes zoster severity and immune responses according to pain trajectories: A community-based prospective cohort study.

The authors aimed to identify determinants of the clinical course of herpes zoster and immunological responses, focusing on pain trajectories. This prospective community-based cohort study involved the analysis of responses to a valid pain survey provided by 375 patients diagnosed with herpes zoster based on clinical symptoms and virus identification by polymerase chain reaction. The authors analyzed most patients for humoral/cell-mediated immune response against varicella-zoster virus at the onset and 3 months post-onset. Six months post-initial visit, patients self-reported pain on a scale of 0 (no pain) to 5 (extremely strong pain) at up to 18 time points. Moreover, the pain trajectories were traced using group-based trajectory modeling. Subsequently, the authors used analysis of covariance to explore predictors and the humoral/cell-mediated immune response according to the pain trajectories. In addition, humoral/cell-mediated immune responses were assessed among each trajectory using paired t tests. Amon the five identified trajectories, two were isolated that particularly developed postherpetic neuralgia, with or without severe acute pain. Cancer therapy and corticosteroid use before herpes zoster onset specifically predicted postherpetic neuralgia without severe acute pain. In contrast, prescription of nonsteroidal anti-inflammatory drugs was uniquely associated with postherpetic neuralgia accompanied by severe acute pain. The aforementioned trajectories with postherpetic neuralgia showed increased antibodies and decreased cell-mediated immunity compared with those without postherpetic neuralgia. The authors could successfully distinguish between postherpetic neuralgia trajectories with and without severe acute pain. The identified key predictors and immunological responses against varicella-herpes zoster contribute further evidence to our understanding of the clinical features of herpes zoster and postherpetic neuralgia.

Multidisciplinary diagnostic approach for fulminant myocarditis related to coronavirus disease 2019 messenger RNA vaccines: a case report.

Background: Recent reports have raised serious concerns regarding acute myocarditis related to coronavirus disease 2019 (COVID-19) messenger RNA (mRNA) vaccines. There are only a few reports of fulminant lymphocytic myocarditis that developed after vaccination. Although the diagnostic approach varied among them, no cases with multidisciplinary diagnostic approaches, including cytokine analysis, have been reported. Case summary: A 59-year-old male with no medical history complained of chest pain a day after receiving the first dose of COVID-19 mRNA (BNT162b2) vaccination. On hospital Day 3, he developed a refractory cardiogenic shock and pulseless ventricular tachycardia, requiring mechanical circulatory support secondary to an exacerbation of myocarditis. Based on the clinical course and examination results, including histologic findings showing a diffuse lymphocytic inflammatory infiltrate with abundant T cells and macrophages in the myocardium, and cardiac magnetic resonance (CMR) findings showing a high-intensity signal on the T2-weighted image and late gadolinium enhancement, he was diagnosed with fulminant myocarditis related to COVID-19 mRNA vaccination. His haemodynamic status gradually improved without immunosuppressive or anti-inflammatory therapy, and he was discharged from hospital on Day 47. To investigate the pathogenesis, we performed cytokine analysis, which showed an increase in serum IP-10, MCP-3, and MIG concentrations, suggesting that Th1-type chemokines preferentially promote cellular immunity. Discussion: In the present case of a patient with fulminant myocarditis following COVID-19 mRNA vaccination diagnosed through histopathological and CMR findings, additional cytokine analysis revealed that elevated levels of cytokines pertaining to Th1 immune response may be involved in disease pathogenesis. A multidisciplinary diagnostic approach is crucial not only to comprehend an individual patient's condition but also to clarify the disease pathogenesis.

Whole-genome sequence and genesis of an avian influenza virus H5N1 isolated from a healthy chicken in a live bird market in Indonesia: accumulation of mammalian adaptation markers in avian hosts.

Background: Influenza A viruses are a major pathogen that causes significant clinical and economic harm to many animals. In Indonesia, the highly pathogenic avian influenza (HPAI) H5N1 virus has been endemic in poultry since 2003 and has caused sporadic deadly infections in humans. The genetic bases that determine host range have not yet been fully elucidated. We analyzed the whole-genome sequence of a recent H5 isolate to reveal the evolution toward its mammalian adaptation. Methods: We determined the whole-genome sequence of A/chicken/East Java/Av1955/2022 (hereafter, "Av1955") from a healthy chicken in April 2022 and conducted phylogenetic and mutational analysis. Results: Phylogenetic analysis revealed that Av1955 belonged to the H5N1 clade 2.3.2.1c (Eurasian lineage). The six gene segments (PB1, PB2, HA, NP, NA, and NS) out of the eight segments derived from viruses of H5N1 Eurasian lineage, one (PB2) from the H3N6 subtype and the remaining one (M) from the H5N1 clade 2.1.3.2b (Indonesian lineage). The donor of the PB2 segment was a reassortant among three viruses of H5N1 Eurasian and Indonesian lineages and the H3N6 subtype. The HA amino acid sequence contained multiple basic amino acids at the cleavage site. Mutation analysis revealed that Av1955 possessed the maximal number of mammalian adaptation marker mutations. Conclusions: Av1955 was a virus of H5N1 Eurasian lineage. The HA protein contains an HPAI H5N1-type cleavage site sequence, while the virus was isolated from a healthy chicken suggesting its low pathogenicity nature. The virus has increased mammalian adaptation markers by mutation and intra- and inter-subtype reassortment, gathering gene segments possessing the most abundant maker mutations among previously circulating viruses. The increasing mammalian adaptation mutation in avian hosts suggests that they might be adaptive to infection in mammalian and avian hosts. It highlights the importance of genomic surveillance and adequate control measures for H5N1 infection in live poultry markets.

Growth, Pathogenesis, and Serological Characteristics of the Japanese Encephalitis Virus Genotype IV Recent Strain 19CxBa-83-Cv.

Genotype IV Japanese encephalitis (JE) virus (GIV JEV) is the least common and most neglected genotype in JEV. We evaluated the growth and pathogenic potential of the GIV strain 19CxBa-83-Cv, which was isolated from a mosquito pool in Bali, Indonesia, in 2019, and serological analyses were also conducted. The growth ability of 19CxBa-83-Cv in Vero cells was intermediate between that of the genotype I (GI) strain Mie/41/2002 and the genotype V (GV) strain Muar, whereas 19CxBa-83-Cv and Mie/41/2002 grew faster than Muar in mouse neuroblastoma cells. The neuroinvasiveness of 19CxBa-83-Cv in mice was higher than that of Mie/41/2002 but lower than that of Muar; however, there were no significant differences in neurovirulence in mice among the three strains. The neutralizing titers of sera from 19CxBa-83-Cv- and Mie/41/2002-inoculated mice against 19CxBa-83-Cv and Mie/41/2002 were similar, whereas the titers against Muar were lower than those of the other two viruses. The neutralizing titers of JE vaccine-inoculated mouse pool serum against 19CxBa-83-Cv and Muar were significantly lower than those against Mie/41/2002. The neutralizing titers against the three viruses were similar in three out of the five serum samples from GI-infected JE patients, although the titers against Mie/41/2002 were higher than those against 19CxBa-83-Cv and Muar in the remaining two sera samples. In summary, we identified the basic characteristics of 19CxBa-83-Cv, but further studies are needed to better understand GIV JEV.

Longitudinal changes in cell-mediated immunity after varicella-zoster virus skin test in the general population; Shozu Herpes Zoster Study: SHEZ study.

Varicella-zoster virus-specific cell-mediated immunity has been associated with the onset and severity of herpes zoster (HZ), and the administration of the HZ vaccine enhanced the immunity. However, limited data is available on the duration of cell-mediated immunity enhancement by soluble antigen of varicella-zoster virus (VZV) skin test. A prospective, community-based cohort study was conducted in Shozu County, Kagawa Prefecture, Japan. Repeated VZV skin tests containing inactivated VZV antigen and blood tests were performed on 365 subjects aged 60 years and older at baseline, 1, 2, and 3 years later. The differential immunity indices of VZV over time for cell-mediated and humoral immunity were evaluated. VZV skin test reaction and ELISpot counts increased significantly at 1, 2, and 3 years later compared to the baseline. However, humoral immunity indices did not change materially over time. Soluble antigen by VZV skin test enhanced VZV-specific cell-mediated immunity, and it persisted for at least 1 year. In addition, the inoculation with inactivated antigens every year by VZV skin test continued to enhance VZV-specific cell-mediated immunity after 2 and 3 years.

ATF1 Restricts Human Herpesvirus 6A Replication via Beta Interferon Induction.

The stimulus-induced cAMP response element (CRE)-binding protein (CREB) family of transcription factors bind to CREs to regulate diverse cellular responses, including proliferation, survival, and differentiation. Human herpesvirus 6A (HHV-6A), which belongs to the Betaherpesvirinae subfamily, is a lymphotropic herpesvirus frequently found in patients with neuroinflammatory diseases. Previous reports implicated the importance of CREs in the HHV-6A life cycle, although the effects of the binding of transcription factors to CREs in viral replication have not been fully elucidated. In this study, we analyzed the role of the CREB family of transcription factors during HHV-6A replication. We found that HHV-6A infection enhanced phosphorylation of the CREB family members CREB1 and activating transcription factor 1 (ATF1). Knockout (KO) of CREB1 or ATF1 enhanced viral gene expression and viral replication. The increase in viral yields in supernatants from ATF1-KO cells was greater than that in supernatants from CREB1-KO cells. Transcriptome sequencing (RNA-seq) analysis showed that sensors of the innate immune system were downregulated in ATF1-KO cells, and mRNAs of beta interferon (IFN-ß) and IFN-regulated genes were reduced in these cells infected with HHV-6A. IFN-ß treatment of ATF1-KO cells reduced progeny viral yields significantly, suggesting that the enhancement of viral replication was caused by a reduction of IFN-ß. Taken together, our results suggest that ATF1 is activated during HHV-6A infection and restricts viral replication via IFN-ß induction. IMPORTANCE Human herpesvirus 6A (HHV-6A) is a ubiquitous herpesvirus implicated in Alzheimer's disease, although its role in its pathogenesis has not been confirmed. Here, we showed that the transcription factor ATF1 restricts HHV-6A replication, mediated by IFN-ß induction. Our study provides new insights into the role of ATF1 in innate viral immunity and reveals the importance of IFN-ß for regulation of HHV-6A replication, which possibly impairs HHV-6A pathogenesis.

Promising Efficacy of a Third Dose of mRNA SARS-CoV-2 Vaccination in Patients Treated with Anti-CD20 Antibody Who Failed 2-Dose Vaccination.

Anti-CD20 antibodies react with CD20 expressed not only on malignant B cells, but also on normal B cells. It has been reported that patients treated with anti-CD20 antibodies had an insufficient response to two-dose mRNA SARS-CoV-2 vaccination. To investigate the efficacy of a third dose in these patients, we investigated serum IgG antibody titers for the S1 protein after a third vaccination in 22 patients treated with the anti-CD20 antibody who failed two-dose vaccination. Results showed that overall, 50% of patients seroconverted. Although no patient who received the third dose within 1 year of the last anti-CD20 antibody administration showed an increase in S1 antibody titer, 69% of patients who received the third dose more than 1 year after the last anti-CD20 antibody administration seroconverted. Our data show that a third dose of vaccination is effective in improving the seroconversion rate in patients treated with the anti-CD20 antibody who failed standard two-dose vaccination.

The association of family history of herpes zoster and the risk of incident herpes zoster: the SHEZ Study.

BACKGROUND: We investigated whether family histories of herpes zoster (HZ) are associated with the risk of incident HZ in a Japanese population. METHODS: A total of 12,522 Japanese residents aged ≥50 years in Shozu County participated in the baseline survey between December 2008 and November 2009 (the participation rate = 72.3%). They were interviewed at baseline by research physicians regarding the registrants' history of HZ. A self-administered questionnaire survey was conducted to evaluate the potential confounding factors. 10,530 participants without a history of HZ were followed up to ascertain the incidence of HZ during 3-years follow-up until the end of November 2012 with Japanese nationals. We estimated hazard ratios (HRs) of incident HZ according to first-degree family histories using the Cox proportional hazard regression after adjusting for age, sex, and other potential confounding factors. RESULTS: Compared to no HZ history of each family member, a history of brother or sister was associated with a higher risk of incident HZ while histories of father and mother were not. The multivariable HR (95%CI) of incident HZ for a history of brother or sister was 1.67 (1.04-2.69). When comparing to no family histories of all first-degree relatives, the multivariable HRs (95%CIs) were 1.34 (0.77-2.34) for a history of brother or sister alone, but 4.81 (1.78-13.00) for a history of mother plus brother or sister. As for the number of family histories, the multivariable HRs (95%CIs) were 1.08 (0.76-1.54) for one relative (father, mother, or brother or sister) and 2.75 (1.13-6.70) for two or more relatives. CONCLUSION: Family histories of mother plus brother or sister and two or more first-degree relatives were associated with a higher risk of incident HZ.

Assessment of Neutralizing Antibody Response Against SARS-CoV-2 Variants After 2 to 3 Doses of the BNT162b2 mRNA COVID-19 Vaccine.

Importance: Although 2 and 3 doses of vaccine have been implemented against the SARS-CoV-2 pandemic, the level of immunity achieved by these additional vaccinations remains unclear. Objective: To investigate the induction of neutralizing antibodies against the SARS-CoV-2 Omicron variant after 2 and 3 doses of the BNT162b2 messenger RNA (mRNA) vaccine among recipients of different ages. Design, Setting, and Participants: A cohort study was conducted from June 1, 2021, to January 12, 2022, among 82 physicians at Kobe University Hospital who had received 2 doses of the BNT162b2 mRNA vaccine. Main Outcomes and Measures: The rates of positive test results and the titers of neutralizing antibodies against the Omicron variant after 2 and 3 doses of the vaccine were compared with those against other variants and compared among 3 age groups (≤38 years [younger age group], 39-58 years [intermediate age group], and ≥59 years [older age group]). Results: A total of 82 physicians (71 men [87%]; median age, 44 years [IQR, 33-58 years]) participated; 31 (38%) were in the younger age group, 32 (39%) were in the intermediate age group, and 19 (23%) were in the older age group. At 2 months after 2 doses of the vaccine, 23 participants (28%) had neutralizing antibodies against the Omicron variant, with a titer of 1.3 (95% CI, 1.2-1.4), which was 11.8-fold (95% CI, 9.9-13.9) lower than the titer against the D614G variant and the lowest among the variants tested. Although the titer of the neutralizing antibody against the Delta variant tended to be low among the older age group (2.9 [95% CI, 2.0-4.1]), the titers of the neutralizing antibody against the Omicron variant were low among all age groups (younger age group, 1.3 [95% CI, 1.1-1.6]; intermediate age group, 1.3 (95% CI, [95% CI, 1.1-1.5]; and older age group, 1.2 [95% CI, 1.0-1.4]). At 7 months after 2 doses of the vaccine, 5 participants (6%) had the neutralizing antibody against the Omicron variant, but after the booster (third dose) vaccination, all 72 participants who received the booster had the neutralizing antibody, and the titer was 41 (95% CI, 34-49), much higher than that at 7 months after 2 doses of the vaccine (1.0 [95% CI, 1.0-1.1]). This increase in titers was observed regardless of age groups; the titers were 44 (95% CI, 32-59) among the younger age group, 44 (95% CI, 32-59) among the intermediate age group, and 30 (95% CI, 22-41) among the older age group. Conclusions and Relevance: In this cohort study of 82 Japanese participants, 2 doses of the BNT162b2 mRNA vaccine did not induce sufficient neutralizing antibody against the Omicron variant. However, booster vaccination was associated with induction of a high level of neutralizing antibodies against the Omicron variant, irrespective of the recipient's age.

Cross-Neutralizing Activity Against Omicron Could Be Obtained in SARS-CoV-2 Convalescent Patients Who Received Two Doses of mRNA Vaccination.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant omicron is now under investigation. We evaluated cross-neutralizing activity against omicron in coronavirus disease 2019 (COVID-19) convalescent patients (n = 23) who had received 2 doses of an mRNA vaccination (BNT162b2 or mRNA-1273). Intriguingly, after the second vaccination, the neutralizing antibody titers of subjects against SARS-CoV-2 variants, including omicron, all became seropositive, and significant fold-increases (21.1-52.0) were seen regardless of the disease severity. Our findings thus demonstrate that 2 doses of mRNA vaccination to SARS-CoV-2 convalescent patients can induce cross-neutralizing activity against omicron.

Regulation of Siglec-7-mediated varicella-zoster virus infection of primary monocytes by cis-ligands.

Varicella-zoster virus (VZV) first infects hematopoietic cells, with the infected cells then acting to distribute the virus throughout the body. Sialic acid-binding immunoglobulin-like lectin (Siglec) family molecules recognize sialic acid-containing molecules on the same cell surface, called cis-ligands, or molecules on other cells or soluble agents, called trans-ligands. Among the Siglec family molecules, Siglec-4 and Siglec-7 mediate VZV infection through association with glycoprotein B (gB). As Siglec-7, but not Siglec-4, is expressed on hematopoietic cells such as monocytes, the regulatory mechanism by which Siglec-7 associates with gB is important to our understanding of VZV infection of blood cells. Here, we found that Siglec-7 is required for VZV to infect human primary monocytes. Furthermore, treatment of primary monocytes with sialidase enhanced both VZV gB binding to monocytes and VZV infectivity. Calcium influx in primary monocytes decreased the expression of Siglec-7 cis-ligands and increased VZV infectivity. These results demonstrate that the Siglec-7 cis-ligands present on primary monocytes play an important role in VZV infection through regulation of the interaction between gB and Siglec-7.

Siglec-7 mediates varicella-zoster virus infection by associating with glycoprotein B.

Sialic acid immunoglobulin-like lectin (Siglec) family molecules are immune regulatory receptors that bind to specific molecules containing sialic acids. Varicella-zoster virus (VZV), a member of the herpesvirus family, infects hematopoietic cells and spreads throughout the body, causing chickenpox, shingles, and, sometimes fatal encephalomyelitis. However, the cellular entry receptors that are required for VZV to infect hematopoietic cells have remained unclear. Here, we found that Siglec-7, mainly expressed on hematopoietic cells, binds to VZV envelope glycoprotein B in a sialic acid-dependent manner. Furthermore, Siglec-7 mediated VZV infection by inducing membrane fusion. Our findings provide the first evidence for a molecular mechanism by which VZV infects hematopoietic cells.