AUTHOR=Enyindah-Asonye Gospel , Nwankwo Anthony , Hogge Christopher , Rahman Mohammad Arif , Helmold Hait Sabrina , Hunegnaw Ruth , Ko Eun-Ju , Hoang Tanya , Venzon David J. , Robert-Guroff Marjorie TITLE=A Pathogenic Role for Splenic B1 Cells in SIV Disease Progression in Rhesus Macaques JOURNAL=Frontiers in Immunology VOLUME=10 YEAR=2019 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.00511 DOI=10.3389/fimmu.2019.00511 ISSN=1664-3224 ABSTRACT=

B1 cells spontaneously produce protective natural antibodies which provide the first line of defense against a variety of pathogens. Although these natural antibodies share similar autoreactive features with several HIV-1 broadly neutralizing antibodies, the role of B1 cells in HIV/SIV disease progression is unknown. We report the presence of human-like B1 cells in rhesus macaques. During chronic SIV infection, we found that the frequency of splenic CD11b+ B1 cells positively correlated with plasma SIV viral load and exhausted T cells. Mechanistically, we discovered that splenic CD11b+ B1 cells express PD-L2 and IL-10, and were able to induce PD-1 upregulation on CD4+ T cells in vitro. These findings suggest that splenic CD11b+ B1 cells may contribute to the regulation of SIV plasma viral load by enhancing T cell exhaustion. Therefore, understanding the mechanisms that govern their function in rhesus macaques may lead to novel therapeutic strategies for impeding HIV/SIV disease progression.