Synergistic effect of two human-like monoclonal antibodies confers protection against orthopoxvirus infection.

The eradication of smallpox was officially declared by the WHO in 1980, leading to discontinuation of the vaccination campaign against the virus. Consequently, immunity against smallpox and related orthopoxviruses like Monkeypox virus gradually declines, highlighting the need for efficient countermeasures not only for the prevention, but also for the treatment of already exposed individuals. We have recently developed human-like monoclonal antibodies (mAbs) from vaccinia virus-immunized non-human primates. Two mAbs, MV33 and EV42, targeting the two infectious forms of the virus, were selected for in vivo evaluation, based on their in vitro neutralization potency. A single dose of either MV33 or EV42 administered three days post-infection (dpi) to BALB/c female mice provides full protection against lethal ectromelia virus challenge. Importantly, a combination of both mAbs confers full protection even when provided five dpi. Whole-body bioimaging and viral load analysis reveal that combination of the two mAbs allows for faster and more efficient clearance of the virus from target organs compared to either MV33 or EV42 separately. The combined mAbs treatment further confers post-exposure protection against the currently circulating Monkeypox virus in Cast/EiJ female mice, highlighting their therapeutic potential against other orthopoxviruses.

Monkeypox virus genomic accordion strategies.

The 2023 monkeypox (mpox) epidemic was caused by a subclade IIb descendant of a monkeypox virus (MPXV) lineage traced back to Nigeria in 1971. Person-to-person transmission appears higher than for clade I or subclade IIa MPXV, possibly caused by genomic changes in subclade IIb MPXV. Key genomic changes could occur in the genome's low-complexity regions (LCRs), which are challenging to sequence and are often dismissed as uninformative. Here, using a combination of highly sensitive techniques, we determine a high-quality MPXV genome sequence of a representative of the current epidemic with LCRs resolved at unprecedented accuracy. This reveals significant variation in short tandem repeats within LCRs. We demonstrate that LCR entropy in the MPXV genome is significantly higher than that of single-nucleotide polymorphisms (SNPs) and that LCRs are not randomly distributed. In silico analyses indicate that expression, translation, stability, or function of MPXV orthologous poxvirus genes (OPGs), including OPG153, OPG204, and OPG208, could be affected in a manner consistent with the established "genomic accordion" evolutionary strategies of orthopoxviruses. We posit that genomic studies focusing on phenotypic MPXV differences should consider LCR variability.

Rapid development of double-hit mRNA antibody cocktail against orthopoxviruses.

The Orthopoxvirus genus, especially variola virus (VARV), monkeypox virus (MPXV), remains a significant public health threat worldwide. The development of therapeutic antibodies against orthopoxviruses is largely hampered by the high cost of antibody engineering and manufacturing processes. mRNA-encoded antibodies have emerged as a powerful and universal platform for rapid antibody production. Herein, by using the established lipid nanoparticle (LNP)-encapsulated mRNA platform, we constructed four mRNA combinations that encode monoclonal antibodies with broad neutralization activities against orthopoxviruses. In vivo characterization demonstrated that a single intravenous injection of each LNP-encapsulated mRNA antibody in mice resulted in the rapid production of neutralizing antibodies. More importantly, mRNA antibody treatments showed significant protection from weight loss and mortality in the vaccinia virus (VACV) lethal challenge mouse model, and a unique mRNA antibody cocktail, Mix2a, exhibited superior in vivo protection by targeting both intracellular mature virus (IMV)-form and extracellular enveloped virus (EEV)-form viruses. In summary, our results demonstrate the proof-of-concept production of orthopoxvirus antibodies via the LNP-mRNA platform, highlighting the great potential of tailored mRNA antibody combinations as a universal strategy to combat orthopoxvirus as well as other emerging viruses.

HDAC5 enhances IRF3 activation and is targeted for degradation by protein C6 from orthopoxviruses including Monkeypox virus and Variola virus.

Histone deacetylases (HDACs) regulate gene expression and innate immunity. Previously, we showed that HDAC5 is degraded during Vaccinia virus (VACV) infection and is a restriction factor for VACV and herpes simplex virus type 1. Here, we report that HDAC5 promotes interferon regulatory factor 3 (IRF3) activation downstream of Toll-IL-1 receptor (TIR) domain-containing adaptor molecule-1 or Sendai virus-mediated stimulation without requiring HDAC activity. Loss of HDAC5-mediated IRF3 activation is restored by re-introduction of HDAC5 but not HDAC1 or HDAC4. The antiviral activity of HDAC5 is antagonized by VACV protein C6 and orthologs from the orthopoxviruses cowpox, rabbitpox, camelpox, monkeypox, and variola. Infection by many of these viruses induces proteasomal degradation of HDAC5, and expression of C6 alone can induce HDAC5 degradation. Mechanistically, C6 binds to the dimerization domain of HDAC5 and prevents homodimerization and heterodimerization with HDAC4. Overall, this study describes HDAC5 as a positive regulator of IRF3 activation and provides mechanistic insight into how the poxviral protein C6 binds to HDAC5 to antagonize its function.

Viruela símica: reporte de un caso clínico / Monkey pox: clinical case report

La viruela símica (monkey pox) es una enfermedad infecciosa causada por un virus del género Orthopoxvirus, usualmente acompañada de síntomas sistémicos como: fiebre, cefalea, mialgias, astenia, erupciones cutáneas o lesiones mucosas. Esta enfermedad se transmite por contacto físico con personas infectadas, materiales o animales infectados. Presentamos el caso de un paciente de 6 años que acude a consulta de Atención Primaria por presentar sintomatología compatible con esta sospecha clínica. Se diagnostica viruela símica bajo reacción en cadena de la polimerasa (PCR) positiva y se da de alta con manejo sintomático ambulatorio. (AU)

Monkeypox is a zoonosis-type disease caused by a virus of the genus Orthopoxvirus. Usually accompanied by systemic symptoms such as fever, headache, myalgia, asthenia, skin rashes or mucosal lesions. This disease is transmitted by physical contact with infected people, infected materials or animals. We present the case of a 6-year-old patient who came to primary care for symptoms compatible with clinical suspicion. Monkeypox was diagnosed under positive PCR and discharged with outpatient symptomatic management. (AU)

The SARS-CoV-2 Spike is a virulence determinant and plays a major role on the attenuated phenotype of Omicron virus in a feline model of infection.

The role of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron BA.1 Spike (S) on disease pathogenesis was investigated. For this, we generated recombinant viruses harboring the S D614G mutation (rWA1-D614G) and the Omicron BA.1 S gene (rWA1-Omi-S) in the backbone of the ancestral SARS-CoV-2 WA1 strain genome. The recombinant viruses were characterized in vitro and in vivo. Viral entry, cell-cell fusion, plaque size, and the replication kinetics of the rWA1-Omi-S virus were markedly impaired when compared to the rWA1-D614G virus, demonstrating a lower fusogenicity and ability to spread cell-to-cell of rWA1-Omi-S. To assess the contribution of the Omicron BA.1 S protein to SARS-CoV-2 pathogenesis, the pathogenicity of rWA1-D614G and rWA1-Omi-S viruses was compared in a feline model. While the rWA1-D614G-inoculated cats were lethargic and showed increased body temperatures on days 2 and 3 post-infection (pi), rWA1-Omi-S-inoculated cats remained subclinical and gained weight throughout the 14-day experimental period. Animals inoculated with rWA1-D614G presented higher infectious virus shedding in nasal secretions, when compared to rWA1-Omi-S-inoculated animals. In addition, tissue replication of the rWA1-Omi-S was markedly reduced compared to the rWA1-D614G, as evidenced by lower viral load in tissues on days 3 and 5 pi. Histologic examination of the nasal turbinate and lungs revealed intense inflammatory infiltration in rWA1-D614G-inoculated animals, whereas rWA1-Omi-S-inoculated cats presented only mild to modest inflammation. Together, these results demonstrate that the S protein is a major virulence determinant for SARS-CoV-2 playing a major role for the attenuated phenotype of the Omicron virus. IMPORTANCE: We have demonstrated that the Omicron BA.1.1 variant presents lower pathogenicity when compared to D614G (B.1) lineage in a feline model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. There are over 50 mutations across the Omicron genome, of which more than two-thirds are present in the Spike (S) protein. To assess the role of the Omicron BA.1 S on virus pathogenesis, recombinant viruses harboring the S D614G mutation (rWA1-D614G) and the Omicron BA.1 Spike gene (rWA1-Omi-S) in the backbone of the ancestral SARS-CoV-2 WA1 were generated. While the Omicron BA.1 S promoted early entry into cells, it led to impaired fusogenic activity and cell-cell spread. Infection studies with the recombinant viruses in a relevant naturally susceptible feline model of SARS-CoV-2 infection here revealed an attenuated phenotype of rWA1-Omi-S, demonstrating that the Omi-S is a major determinant of the attenuated disease phenotype of Omicron strains.

Never Let a Good Outbreak Go to Waste.

The multinational outbreak of mpox (formerly known as monkeypox) that began in 2022 resulted in more than 90,000 reported cases, over 150 deaths, and - importantly - a coordinated international response to a rapidly spreading infectious disease.1 Because of decades of global preparedness efforts, vaccines and therapeutics for a related orthopox virus (smallpox) were available in many global stockpiles. Few of these medical countermeasures were specifically designed, evaluated, or approved for use against mpox disease, requiring the global scientific community to identify how best to quickly translate what was known into what was needed.

Orally available nucleoside analog UMM-766 provides protection in a murine model of orthopox disease.

Although smallpox has been eradicated, other orthopoxviruses continue to be a public health concern as exemplified by the ongoing Mpox (formerly monkeypox) global outbreak. While medical countermeasures (MCMs) previously approved by the Food and Drug Administration for the treatment of smallpox have been adopted for Mpox, previously described vulnerabilities coupled with the questionable benefit of at least one of the therapeutics during the 2022 Mpox outbreak reinforce the need for identifying and developing other MCMs against orthopoxviruses. Here, we screened a panel of Merck proprietary small molecules and identified a novel nucleoside inhibitor with potent broad-spectrum antiviral activity against multiple orthopoxviruses. Efficacy testing of a 7-day dosing regimen of the orally administered nucleoside in a murine model of severe orthopoxvirus infection yielded a dose-dependent increase in survival. Treated animals had greatly reduced lesions in the lung and nasal cavity, particularly in the 10 µg/mL dosing group. Viral levels were also markedly lower in the UMM-766-treated animals. This work demonstrates that this nucleoside analog has anti-orthopoxvirus efficacy and can protect against severe disease in a murine orthopox model.IMPORTANCEThe recent monkeypox virus pandemic demonstrates that members of the orthopoxvirus, which also includes variola virus, which causes smallpox, remain a public health issue. While currently FDA-approved treatment options exist, risks that resistant strains of orthopoxviruses may arise are a great concern. Thus, continued exploration of anti-poxvirus treatments is warranted. Here, we developed a template for a high-throughput screening assay to identify anti-poxvirus small-molecule drugs. By screening available drug libraries, we identified a compound that inhibited orthopoxvirus replication in cell culture. We then showed that this drug can protect animals against severe disease. Our findings here support the use of existing drug libraries to identify orthopoxvirus-targeting drugs that may serve as human-safe products to thwart future outbreaks.

In vitro replicative potential of an HIV-1/MO intergroup recombinant virus compared to HIV-1/M and HIV-1/O parental viruses.

Genetic recombination is one of the major evolution processes of HIV-1. Despite their great genetic divergence, HIV-1 groups M and O can generate HIV-1/MO intergroup recombinants. The current description of 20 HIV-1/MO unique recombinant forms suggests a possible benefit of the recombination. The aim of this work was to study in vitro the replicative potential of HIV-1/MO recombinant forms. This analysis was based on a simple recombination pattern, [Ogag/pol-Menv], harboring a breakpoint in Vpr. A chimeric infectious molecular clone, pOM-TB-2016 was synthesized from HIV-1/M subtype B and HIV-1/O subgroup T and recombinant viruses were obtained by transfection/co-culture. To compare the replicative potential of these viruses, two markers were monitored in culture supernatants: Reverse Transcriptase (RT) activity and P24 antigen concentration. The results showed a superiority of the group M parental virus compared to group O for both markers. In contrast, for the recombinant virus, RT activity data did not overlap with the concentration of P24 antigen, suggesting a hybrid behavior of the recombinant, in terms of enzyme activity and P24 production. These results highlighted many hypotheses about the impact of recombination on replicative potential and demonstrated again the significant plasticity of HIV genomes and their infinite possibility of evolution.

Orthopoxvirus-Specific T-Cell Responses in Convalescent Mpox Patients.

Orthopoxvirus-specific T-cell responses were analyzed in 10 patients who had recovered from Mpox including 7 people with human immunodeficiency virus (PWH). Eight participants had detectable virus-specific T-cell responses, including a PWH who was not on antiretroviral therapy and a PWH on immunosuppressive therapy. These 2 participants had robust polyfunctional CD4+ T-cell responses to peptides from the 121L vaccinia virus (VACV) protein. T-cells from 4 of 5 HLA-A2-positive participants targeted at least 1 previously described HLA-A2-restricted VACV epitope, including an epitope targeted in 2 participants. These results advance our understanding of immunity in convalescent Mpox patients.

Epidemiology of the 2022 Mpox Outbreak in the US Veterans Health Administration.

BACKGROUND: In May 2022, mpox cases were reported in nonendemic countries, including the United States. We examined mpox infections in the Veterans Health Administration (VHA). METHODS: Mpox diagnostic and whole genome sequencing (WGS) results, demographics, risk factors, hospitalizations, exposures, deaths, and pharmacy and immunization data were obtained from VHA data sources (23 May 2022-31 May 2023). RESULTS: Of 1144 Veterans tested, 251 (21.9%) were presumptive positive for nonvariola orthopoxvirus (NVO) or confirmed positive for NVO and Monkeypox virus (MPXV). Incidence rate was 7.5 per 100 000 Veterans in care, with the highest rate observed in Veterans aged 25-34 years (13.83 cases per 100 000). Higher odds of NVO or NVO/MPXV positivity was associated with male sex; non-Hispanic Black race/ethnicity; syphilis or human immunodeficiency virus (HIV) positivity; or genital/rectal sample site, whereas older age and vaccination with JYNNEOS or vaccinia (smallpox) had lower odds. Among 209 with confirmatory testing, 90.4% reported intimate contact and/or an epidemiological link, 84.5% were men who have sex with men (MSM), 24.2% received tecovirimat, and 8.1% were hospitalized with 1 death. Eighty-six sequenced samples had evaluable WGS results. All were clade IIb, representing 10 different lineages from 20 states and the District of Columbia. CONCLUSIONS: Mpox affected younger, MSM, non-Hispanic Black, and HIV/syphilis-positive men among US Veterans. Viral diversity was noted across geographic regions. At-risk Veterans would benefit from vaccination and risk reduction strategies for mpox and other sexually transmitted infections.

Intranasal immunization with the recombinant measles virus encoding the spike protein of SARS-CoV-2 confers protective immunity against COVID-19 in hamsters.

BACKGROUND: As the nasal mucosa is the initial site of infection for COVID-19, intranasal vaccines are more favorable than conventional vaccines. In recent clinical studies, intranasal immunization has been shown to generate higher neutralizing antibodies; however, there is a lack of evidence on sterilizing immunity in the upper airway. Previously, we developed a recombinant measles virus encoding the spike protein of SARS-CoV-2 (rMeV-S), eliciting humoral and cellular immune responses against SARS-CoV-2. OBJECTIVES: In this study, we aim to provide an experiment on nasal vaccines focusing on a measles virus platform as well as injection routes. STUDY DESIGN: Recombinant measles viruses expressing rMeV-S were prepared, and 5 × 105 PFUs of rMeV-S were administered to Syrian golden hamsters via intramuscular or intranasal injection. Subsequently, the hamsters were challenged with inoculations of 1 × 105 PFUs of SARS-CoV-2 and euthanized 4 days post-infection. Neutralizing antibodies and RBD-specific IgG in the serum and RBD-specific IgA in the bronchoalveolar lavage fluid (BALF) were measured, and SARS-CoV-2 clearance capacity was determined via quantitative reverse-transcription PCR (qRT-PCR) analysis and viral titer measurement in the upper respiratory tract and lungs. Immunohistochemistry and histopathological examinations of lung samples from experimental hamsters were conducted. RESULTS: The intranasal immunization of rMeV-S elicits protective immune responses and alleviates virus-induced pathophysiology, such as body weight reduction and lung weight increase in hamsters. Furthermore, lung immunohistochemistry demonstrated that intranasal rMeV-S immunization induces effective SARS-CoV-2 clearance that correlates with viral RNA content, as determined by qRT-PCR, in the lung and nasal wash samples, SARS-CoV-2 viral titers in lung, nasal wash, BALF samples, serum RBD-specific IgG concentration, and RBD-specific IgA concentration in the BALF. CONCLUSION: An intranasal vaccine based on the measles virus platform is a promising strategy owing to the typical route of infection of the virus, the ease of administration of the vaccine, and the strong immune response it elicits.

The imperative for quality control programs in Monkeypox virus DNA testing by PCR: CIBERINFEC quality control.

To evaluate molecular assays for Mpox diagnosis available in various clinical microbiology services in Spain through a quality control (QC) approach. A total of 14 centers from across Spain participated in the study. The Reference Laboratory dispatched eight serum samples and eight nucleic acid extracts to each participating center. Some samples were spiked with Mpox or Vaccinia virus to mimic positive samples for Mpox or other orthopox viruses. Participating centers provided information on the results obtained, as well as the laboratory methods used. Among the 14 participating centers seven different commercial assays were employed, with the most commonly used kit being LightMix Modular Orthopox/Monkeypox (Mpox) Virus (Roche®). Of the 12 centers conducting Mpox determinations, concordance ranged from 62.5% (n = 1) to 100% (n = 11) for eluates and from 75.0% (n = 1) to 100% (n = 10) for serum. Among the 10 centers performing Orthopoxvirus determinations, a 100% concordance was observed for eluates, while for serum, concordance ranged from 87.5% (n = 6) to 100% (n = 4). Repeatedly, 6 different centers reported a false negative in serum samples for Orthopoxvirus diagnosis, particularly in a sample with borderline Ct = 39. Conversely, one center, using the TaqMan™ Mpox Virus Microbe Detection Assay (Thermo Fisher), reported false positives in Mpox diagnosis for samples spiked with vaccinia virus due to cross-reactions. We observed a positive correlation of various diagnostic assays for Mpox used by the participating centers with the reference values. Our results highlight the significance of standardization, validation, and ongoing QC in the microbiological diagnosis of infectious diseases, which might be particularly relevant for emerging viruses.

Extraction-free LAMP assays for generic detection of Old World Orthopoxviruses and specific detection of Mpox virus.

Mpox is a neglected zoonotic disease endemic in West and Central Africa. The Mpox outbreak with more than 90,000 cases worldwide since 2022 generated great concern about future outbreaks and highlighted the need for a simple and rapid diagnostic test. The Mpox virus, MPV, is a member of the Orthopoxvirus (OPV) genus that also contains other pathogenic viruses including variola virus, vaccinia virus, camelpox virus, and cowpox virus. Phylogenomic analysis of 200 OPV genomes identified 10 distinct phylogroups with the New World OPVs placed on a very long branch distant from the Old World OPVs. Isolates derived from infected humans were found to be distributed across multiple phylogroups interspersed with isolates from animal sources, indicating the zoonotic potential of these viruses. In this study, we developed a simple and sensitive colorimetric LAMP assay for generic detection of Old World OPVs. We also developed an MPV-specific probe that differentiates MPV from other OPVs in the N1R LAMP assay. In addition, we described an extraction-free protocol for use directly with swab eluates in LAMP assays, thereby eliminating the time and resources needed to extract DNA from the sample. Our direct LAMP assays are well-suited for low-resource settings and provide a valuable tool for rapid and scalable diagnosis and surveillance of OPVs and MPV.

How to distinguish mpox from its mimickers: An observational retrospective cohort study.

During the current global outbreak of mpox (formerly monkeypox), atypical features were frequently described outside endemic areas, raising concerns around differential diagnosis. In this study, we included 372 adult patients who had clinical signs consistent with mpox and who were screened using non-variola orthopoxvirus specific quantitative polymerase chain reaction (PCR) between 15 May and 15 November 2022 at the University Hospital Institute Méditerranée Infection, Marseille, France. At least one clinical sample was positive for 143 (38.4%) of these patients and 229 (61.6%) were negative. Clinically, patients who had mpox presented more frequently with systemic signs (69.9% vs. 31.0%, p < 10-6 ) including fever (51.0% vs. 30.1%, p < 10-3 ), myalgia (33.5% vs. 17.9%, p = 0.002), and lymphadenopathy (38.5% vs. 13.1%, p < 10-6 ). Among the patients who were negative for the non-variola orthopoxvirus, an alternative diagnosis was identified in 58 of them (25.3%), including chickenpox (n = 30, 13.1%), syphilis (n = 9, 4%), bacterial skin infection (n = 8, 3.5%), gonococcus (n = 5, 2.2%), HSV infection (n = 5, 2.2%), and histoplasmosis (n = 1, 0.4%). Overall, in the current outbreak, we show that mpox has a poorly specific clinical presentation. This reinforces the importance of microbiological confirmation. In symptomatic patients who are negative for the monkeypox virus by PCR, a broad differential diagnosis should be maintained.

Rapid and sensitive one-tube detection of mpox virus using RPA-coupled CRISPR-Cas12 assay.

Mpox is caused by a zoonotic virus belonging to the Orthopoxvirus genus and the Poxviridae family. In this study, we develop a recombinase polymerase amplification (RPA)-coupled CRISPR-Cas12a detection assay for the mpox virus. We design and test a series of CRISPR-derived RNAs(crRNAs) targeting the conserved D6R and E9L genes for orthopoxvirus and the unique N3R and N4R genes for mpox viruses. D6R crRNA-1 exhibits the most robust activity in detecting orthopoxviruses, and N4R crRNA-2 is able to distinguish the mpox virus from other orthopoxviruses. The Cas12a/crRNA assay alone presents a detection limit of 108 copies of viral DNA, whereas coupling RPA increases the detection limit to 1-10 copies. The one-tube RPA-Cas12a assay can, therefore, detect viral DNA as low as 1 copy within 30 min and holds the promise of providing point-of-care detection for mpox viral infection.

Development of a novel serological assay for the detection of mpox infection in vaccinated populations.

In 2022 the World Health Organization declared a Public Health Emergency for an outbreak of mpox, the zoonotic Orthopoxvirus (OPV) affecting at least 104 nonendemic locations worldwide. Serologic detection of mpox infection is problematic, however, due to considerable antigenic and serologic cross-reactivity among OPVs and smallpox-vaccinated individuals. In this report, we developed a high-throughput multiplex microsphere immunoassay using a combination of mpox-specific peptides and cross-reactive OPV proteins that results in the specific serologic detection of mpox infection with 93% sensitivity and 98% specificity. The New York State Non-Vaccinia Orthopoxvirus Microsphere Immunoassay is an important tool to detect subclinical mpox infection and understand the extent of mpox spread in the community through retrospective analysis.

Prevalence of Undiagnosed Monkeypox Virus Infections during Global Mpox Outbreak, United States, June-September 2022.

Since May 2022, mpox has been identified in 108 countries without endemic disease; most cases have been in gay, bisexual, or other men who have sex with men. To determine number of missed cases, we conducted 2 studies during June-September 2022: a prospective serologic survey detecting orthopoxvirus antibodies among men who have sex with men in San Francisco, California, and a retrospective monkeypox virus PCR testing of swab specimens submitted for other infectious disease testing among all patients across the United States. The serosurvey of 225 participants (median age 34 years) detected 18 (8.0%) who were orthopoxvirus IgG positive and 3 (1.3%) who were also orthopoxvirus IgM positive. The retrospective PCR study of 1,196 patients (median age 30 years; 54.8% male) detected 67 (5.6%) specimens positive for monkeypox virus. There are likely few undiagnosed cases of mpox in regions where sexual healthcare is accessible and patient and clinician awareness about mpox is increased.

Molecular investigations of camelpox virus circulating in dromedary camel population in Rajasthan, India.

Camelpox is an important viral disease of dromedary camel in Rajasthan, India. In the present study, partial C18L gene sequences (n = 6) of camelpox virus (CMLV) obtained in an outbreak in Bikaner, Rajasthan, India in year 2022 were compared with other similar sequences obtained in the past in similar geographical location. Clinical and epidemiological features of the disease were also compared. Genomic study suggested variations in C18L gene sequences obtained in the present outbreak from those obtained during the past outbreaks. CMLV were genetically different from cowpox viruses, but appeared identical to CMLV causing disease in Israel, Egypt and Kazakhstan. Genomes of CMLV virus circulating in dromedary camel population of Rajasthan, India appeared diverse and changing, hence complete genome sequencing and identification of genomic changes altering infectivity and pathogenicity is warranted for designing control strategies.

Coxsackievirus B3 elicits a sex-specific CD8+ T cell response which protects female mice.

Sex is a significant contributor to the outcome of human infections. Males are frequently more susceptible to viral, bacterial, and fungal infections, often attributed to weaker immune responses. In contrast, a heightened immune response in females enables better pathogen elimination but leaves females more predisposed to autoimmune diseases. Unfortunately, the underlying basis for sex-specific immune responses remains poorly understood. Here, we show a sex difference in the CD8+ T cell response to an enteric virus, Coxsackievirus B3 (CVB3). We found that CVB3 induced expansion of CD8+ T cells in female mice but not in male mice. CVB3 also increased the proportion and number of CD11ahiCD62Llo CD8+ T cells in female mice, indicative of activation. This response was independent of the inoculation route and type I interferon. Using a recombinant CVB3 virus expressing a model CD8+ T cell epitope, we found that the expansion of CD8+ T cells in females is viral-specific and not due to bystander activation. Finally, the depletion of CD8+ T cells, prior to infection, led to enhanced mortality, indicating that CD8+ T cells are protective against CVB3 in female mice. These data demonstrate that CVB3 induces a CD8+ T cell response in female mice and highlight the importance of sex-specific immune responses to viral pathogens.