Plasma cells are formed in waning germinal centers via an affinity-independent process

Abstract

Long-lived plasma cells (PCs) secrete antibodies that can provide sustained immunity against infection. It has been proposed that high affinity cells are preferentially selected into this compartment, potentiating the immune response. Here we used single cell RNA-seq to track the development of Ighg2A10 cells, specific for the Plasmodium falciparum circumsporozoite protein (PfCSP) within the germinal center (GC). We identified cells differentiating into memory B cells (MBC) or PCs and estimated their affinity by V(D)J sequencing. While pre-memory cells were of lower affinity than GC B cells generally, the affinity of pre-PC cells was indistinguishable. Rather, a larger proportion of cells differentiated into PCs in waning GCs. These later emigrants replaced early arrivals in the bone marrow allowing the development of a high affinity PC compartment.