Abstract Plasma cell subsets vary in their lifespans and ability to sustain humoral immunity. We conducted a genome-wide CRISPR-Cas9 screen in myeloma cells for factors that promote surface expression of CD98, a marker of longevity in mouse plasma cells. A large fraction of genes found to promote CD98 expression in this screen are involved in secretory and other vesicles, including subunits of the V-type ATPase complex. Genetic ablation and chemical inhibition of V-type ATPases in myeloma cells and primary plasma cells, respectively, reduced antibody secretion. Mouse and human long-lived plasma cells had greater numbers of acidified vesicles than their short-lived counterparts, and this correlated with increased antibody secretory capacity. The screen also revealed a requirement for the signaling adapter MYD88 in CD98 expression. Plasma cell–specific deletion of Myd88 led to reduced survival and antibody secretion by antigen-specific cells in vivo and unresponsiveness to BAFF and APRIL ex vivo. These data reveal novel regulators that link plasma cell secretory capacity and lifespan.
D’Souza et al. (Sun,) studied this question.