Wiskott-Aldrich syndrome (WAS) is a rare x-linked monogenic immunodeficiency disease, caused by the mutation of WAS gene encoding WAS protein (WASp). Previous findings in WAS patients show B cell perturbations in the periphery, characterized by diminished B-cell numbers and phenotype abnormalities, including reduced frequency of classical CD27+ memory B cells (MBCs), accompanied by an unusual expansion of atypical CD21low MBCs. The mechanism underlying these abnormalities in MBCs developmental pathway has not been completely dissected. In this study, WASp knock-out mice undergone with acute lymphocytic choriomeningitis virus (LCMV) infection was used as a model to investigate the effects of WASp deficiency on the differentiation of MBCs and the possible mechanisms. We found that by day 11 after infection, the proportion of classical IgG2c+ MBCs was dramatically decreased, this was accompanied by a corresponding increase in the proportion of atypical CD21low MBCs. Using single-cell RNA sequencing (scRNA-seq), we also identified WASp deficiency promoted the formation of atypical MBCs during acute viral infection. Remarkably, our study revealed a marked reduction of WASp expression in atypical MBCs. Overall, our data show that WASp is differentially expressed in MBCs subsets, and manipulates the fate of MBCs during acute LCMV infection.
Zhang et al. (Wed,) studied this question.