Latent gammaherpesvirus infection licenses age-associated B cells for pathogenicity during EAE and MS

• Published in: The Journal of immunology (1950) 2020-05, Vol.204 (1_Supplement), p.58-58.10
• Main Authors: Mouat, Isobel, Allanach, Jessica, Shanina, Iryna, Vorobeychik, Galina, Horwitz, Marc S
• Format: Article
• Language: English
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.204.Supp.58.10

Epstein-Barr virus (EBV) has long been implicated in multiple sclerosis (MS), though its mechanism of contribution remains unknown. Age-associated B cells (ABCs) are known to expand and persist following viral infection and are increased in MS patients. We hypothesize that EBV infection expands the number of ABCs and skews the population towards a Th1 inflammatory phenotype, leading them to function pathogenically in MS. To explore how the EBV-primed ABC population contributes to MS we have utilized the in vivo models of EBV, gammaherpesvirus 68 (gHV68), and MS, and MOG35–55 experimental autoimmune encephalomyelitis (EAE). We observe that ABCs display distinct phenotypes during gHV68 infection and EAE: ABCs secrete anti-viral IFNg during gHV68 infection and IL10 during EAE. Intriguingly, latent gHV68 infection prior to EAE results in a heterogeneous ABC phenotype, with IL10 and IFNg-secreting subsets. As IFNg is pathogenic during EAE and MS, and IL10 is protective, the gHV68-EAE ABCs display a more pathogenic phenotype compared to EAE alone, corresponding to the enhanced clinical course during gHV68-EAE. Knocking out ABCs results in an amelioration of disease in gHV68-EAE, but not EAE alone, further substantiating that gHV68 infection drives ABCs towards pathogenicity. In MS patients we observe an increased number and altered inflammatory phenotype of circulating ABCs compared to age and sex-matched healthy controls. These findings indicate that gHV68 and EBV prime ABCs to contribute pathogenically during EAE and MS and suggest that ABCs may be a therapeutic target.