Antiviral CD19+CD27+ Memory B Cells Are Associated with Protection from Recurrent Asymptomatic Ocular Herpes Infection

Reactivation of herpes simplex virus 1 (HSV-1) from latently infected neurons of the trigeminal ganglia (TG) leads to blinding recurrent herpetic disease in symptomatic (SYMP) individuals. Although the role of T cells in herpes immunity seen in asymptomatic (ASYMP) individuals is heavily explored, the role of B cells is less investigated. In the present study, we evaluated whether B cells are associated with protective immunity against recurrent ocular herpes. The frequencies of circulating HSV-specific memory B cells and of memory follicular helper T cells (CD4+ Tfh cells), that help B cells produce antibodies, were compared between HSV-1 infected SYMP and ASYMP individuals. The levels of IgG/IgA and neutralizing antibodies were compared in SYMP and ASYMP individuals. We found that: (i) the ASYMP individuals had increased frequencies of HSV-specific CD19+CD27+ memory B cells; and (ii) high frequencies of HSV-specific switched IgG+CD19+CD27+ memory B cells detected in ASYMP individuals were directly proportional to high frequencies of CD45R0+CXCR5+CD4+ memory Tfh cells. However, no differences were detected in the level of HSV-specific IgG/IgA antibodies in SYMP and ASYMP individuals. Using the UV-B-induced HSV-1 reactivation mouse model, we found increased frequencies of HSV-specific antibody-secreting plasma HSV-1 gD+CD138+ B cells within the TG and circulation of ASYMP mice compared to SYMP mice. In contrast, no significant differences in the frequencies of B cells were found in the cornea, spleen, and bone-marrow. Our findings suggest that circulating antibody-producing HSV-specific memory B cells recruited locally to the TG may contribute to protection from symptomatic recurrent ocular herpes. IMPORTANCE Reactivation of herpes simplex virus 1 (HSV-1) from latently infected neurons of the trigeminal ganglia (TG) leads to blinding recurrent herpetic disease in symptomatic (SYMP) individuals. Although the role of T cells in herpes immunity against blinding recurrent herpetic disease is heavily explored, the role of B cells is less investigated. In the present study, we found that in both asymptomatic (ASYMP) individuals and ASYMP mice there was increased frequencies of HSV-specific memory B cells that were directly proportional to high frequencies of memory Tfh cells. Moreover, following UV-B induce reactivation, we found increased frequencies of HSV-specific antibody-secreting plasma B cells within the TG and circulation of ASYMP mice, compared to SYMP mice. Our findings suggest that circulating antibody-producing HSV-specific memory B cells recruited locally to the TG may contribute to protection from recurrent ocular herpes.


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Although the role of CD4 + and CD8 + T cells against HSV-1 reactivation is heavily explored, the 88 role of B cells is less investigated. Unlike T cell memory which can be tissue-resident, recent studies

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MBCs remain in the peripheral circulation and secrete antibodies when they are re-exposed to their 92 cognate antigen (16). MBCs in HSV-1 infected humans is not feasible to explore due to the low 93 abundance of MBCs in peripheral blood. In fact, the low abundance of MBCs for any specific virus antibody they secrete upon activation (17,18). In this study, we explored the frequency of MBCs 97 found in the circulation of asymptomatic and symptomatic HSV-1 infected individuals by two different 98 approaches -antigen-specific flow cytometry and ELISPOT.

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To understand the mechanisms that cause a differential humoral response between SYMP

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Using the UV-B-induced HSV-1 reactivation mouse model, the frequencies of HSV-1 specific 109 memory B and plasma cells were compared between SYMP and ASYMP mice by flow cytometry and 110 ELISpot within cornea, TG, spleen and bone marrow and circulation. We found a significant increase 111 in the frequencies of HSV-specific antibody-secreting plasma B cells within the TG of ASYMP mice 112 compared to SYMP mice. In contrast, no significant differences were found in the cornea, spleen and 113 bone-marrow. Our findings suggest that circulating HSV-specific antibody-producing memory B cells 114 recruited locally at the TG site could contribute to protection from symptomatic recurrent ocular

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Data are expressed as the mean + SD. Results were considered statistically significant at p < 0.05.     . 1C and 1D). The ELISPOT findings confirm flow cytometry that ASYMP individuals have increased circulating memory cells binding to HSV-1 gD compared to SYMP 245 individuals. As expected, HSV-1 and HSV-2 negative individuals showed no detectable HSV-1 gD 246 specific IgG/ IgA ASC compared to ASYMP and SYMP herpes positive subjects (Fig. 1C).

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Immune cells from peripheral blood, spleen and bone marrow were stimulated with mouse