Seroprevalence of group B Coxsackieviruses: Retrospective study in an Italian population

Seasonal Testing, Results, and Effect of the Pandemic on Coxsackievirus Serum Studies

Coxsackieviruses (CVs) are common causes of infections and can be life-threatening. Unfortunately, rigorous studies guiding the clinician in interpreting CV serum antibody titer testing is lacking. To explore the epidemiology of circulating CVs and the serological test utility in aiding diagnosis of CV infections in our community, we obtained results of CV immunologic diagnostic tests between 2018 and 2022 from a regional healthcare database. For CV type A, rare individuals had positive CF (complement fixation) tests whereas all 16 individuals with IFA testing showed at least one positive serotype. For CV type B CF testing, 52.2% of 222 patients had at least one serotype positive, with B5 being most common and also the most common with higher titers (14.8% with ≥1:32). We found a significant reduction in seropositivity rate during the pandemic in 2020 compared to 2018, which continued through 2022 (OR: 0.2, 95% CI: 0.08-0.49, p-value < 0.001). During the pandemic, the seasonal pattern of positive tests varied from the pre-pandemic pattern. Testing for CVs was increased after the first year of the pandemic. Overall, the variability by month and seasonal change in our data support that CF testing can be used to identify recent CVB infection.

Investigating the virulence of coxsackievirus B6 strains and antiviral treatments in a neonatal murine model

Coxsackievirus B6 (CVB6), a member of the human enterovirus family, is associated with severe diseases such as myocarditis in children. However, to date, only a limited number of CVB6 strains have been identified, and their characterization in animal models has been lacking. To address this gap, in this study, a neonatal murine model of CVB6 infection was established to compare the replication and virulence of three infectious-clone-derived CVB6 strains in vivo. The results showed that following challenge with a lethal dose of CVB6 strains, the neonatal mice rapidly exhibited a series of clinical signs, such as weight loss, limb paralysis, and death. For the two high-virulence CVB6 strains, histological examination revealed myocyte necrosis in skeletal and cardiac muscle, and immunohistochemistry confirmed the expression of CVB6 viral protein in these tissues. Real-time PCR assay also revealed higher viral loads in the skeletal and cardiac muscle than in other tissues at different time points post infection. Furthermore, the protective effect of passive immunization with antisera and a neutralizing monoclonal antibody against CVB6 infection was evaluated in the neonatal mouse model. This study should provide insights into the pathogenesis of CVB6 and facilitate further research in the development of vaccines and antivirals against CVBs.

Unusual Presentation of Coxsackievirus B and Methicillin-Sensitive Staphylococcus aureus Cellulitis Causing Sepsis

The clinical association between Coxsackievirus B (CVB) and methicillin-sensitive Staphylococcus aureus (MSSA) has not been well established in the current literature. Here, we report a case of a 29-year-old male who presented with fever and malaise 24 hours after noticing a pruritic lesion on the anterior foreleg that resembled a mosquito bite. After multiple ED visits, laboratory studies, and imaging tests, the patient was admitted for treatment of high fevers and pancytopenia. The final diagnosis was viral sepsis complicated by co-infection with MSSA.

Construction and verification of an infectious cDNA clone of coxsackievirus B5

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An infectious cDNA clone of CV-B5 was constructed.

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The rescued and parental virus possessed similar biological characteristics.

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The virulence of the rescued virus was similiar to that of the parental virus.

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Viral distribution and tissue tropism of those two viruses were in agreement.

Analysis of the long noncoding RNA profiles of RD and SH-SY5Y cells infected with coxsackievirus B5, using RNA sequencing

Hand, foot, and mouth disease caused by coxsackievirus B5 (CV-B5) is a considerable threat to infant health, especially with regard to neurological damage. Long noncoding RNAs (lncRNAs) are known to play pivotal roles in virus-host interactions. However, the roles of lncRNAs in CV-B5-host interactions have not yet been elucidated. In the current study, we used RNA sequencing to determine the expression profiles of lncRNAs in CV-B5-infected human rhabdomyosarcoma (RD) and SH-SY5Y cells. Our results showed that, of the differentially expressed lncRNAs, 508 were upregulated and 760 were downregulated in RD cells. Of these, 46.2% were long noncoding intergenic RNAs (lincRNAs), 28.6% were antisense lncRNAs, 24.1% were sense overlapping lncRNAs, and 1.0% were sense intronic lncRNAs. Moreover, 792 lncRNAs were upregulated and 811 lncRNAs were downregulated in SH-SY5Y cells, 48.6% of which were lincRNAs, 34.7% were antisense lncRNAs, 16.0% were sense overlapping lncRNAs, and 0.8% were sense intronic lncRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that lncRNAs that were differentially expressed in CV-B5-infected RD cells were associated with disease, and those differentially expressed in SH-SY5Y cells were involved in signaling pathways. RT-qPCR analysis of seven lncRNAs supported these results. Moreover, our study revealed that lncRNA-IL12A inhibits viral replication. We conclude that lncRNAs constitute potential novel molecular targets for the prevention and treatment of CV-B5 infection and also may serve to distinguish neurogenic diseases caused by CV-B5 infection.

Coxsackievirus B5 virus-like particle vaccine exhibits greater immunogenicity and immunoprotection than its inactivated counterpart in mice

Coxsackievirus B group 5 (CVB5) represents one of the major pathogens that cause diseases such as hand, foot and mouth disease (HFMD) and aseptic meningitis et al. Currently, no specific drugs and vaccines are available, and a safe and effective CVB5 vaccine is of great value for control of the diseases. In this study, CVB5 P1 precursor and 3CD protease were co-expressed in Sf9 cells by using a baculovirus expression system. The P1 was processed by 3CD and self-assembled into CVB5 virus-like particles (VLPs). VP1 and VP3 capsid proteins of CVB5 could be detected by SDS-PAGE and Western blotting. Transmission electron microscopy revealed that the CVB5 VLPs were spherical particles with a diameter of about 30 nm, mimicking wild-type CVB5 virus. Our study showed that the total IgG and neutralizing antibodies induced by CVB5 VLPs were higher than those induced by inactivated vaccine. More importantly, the CVB5 VLPs conferred full protection to the CVB5-challenged suckling mice via passive immunity while protection efficiency of the inactivated vaccine was only 80%. The CVB5 VLPs vaccine could protect the limb muscles, brain, and heart tissues of suckling mice from CVB5-induced damage. These results demonstrated that the CVB5 VLPs vaccine possessed stronger immunogenicity and provided more robust immunoprotection than the inactivated CVB5 vaccine, suggesting that the CVB5 VLPs promise to be a CVB5 vaccine candidate in future.

Comparison of Monoclonal Gammopathies Linked to Poliovirus or Coxsackievirus vs. Other Infectious Pathogens

Chronic stimulation by infectious pathogens or self-antigen glucosylsphingosine (GlcSph) can lead to monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM). Novel assays such as the multiplex infectious antigen microarray (MIAA) and GlcSph assays, permit identification of targets for >60% purified monoclonal immunoglobulins (Igs). Searching for additional targets, we selected 28 purified monoclonal Igs whose antigen was not represented on the MIAA and GlcSph assays; their specificity of recognition was then analyzed using microarrays consisting of 3760 B-cell epitopes from 196 pathogens. The peptide sequences PALTAVETG and PALTAAETG of the VP1 coat proteins of human poliovirus 1/3 and coxsackievirus B1/B3, respectively, were specifically recognized by 6/28 monoclonal Igs. Re-analysis of patient cohorts showed that purified monoclonal Igs from 10/155 MGUS/SM (6.5%) and 3/147 MM (2.0%) bound to the PALTAVETG or PALTAAETG epitopes. Altogether, PALTAV/AETG-initiated MGUS are not rare and few seem to evolve toward myeloma.