Distinctions among Circulating Antibody-Secreting Cell Populations, Including @entity12950 Cells, in XXXX Adult Peripheral Blood.

@entity1 @entity2225 @entity13221 @entity12910 @entity3053 @entity2731 @entity2945 @entity12950
UNASSIGNED: @entity1 Ab-secreting cell (ASC) populations in circulation are not well studied. In addition to @entity12950 ( @entity2225 (+) @entity2731 (+) @entity3053 (lo/int) @entity12910 (+)) cell and conventional plasmablast (PB) ( @entity2225 - @entity2731 (hi) @entity3053 (hi)) cell populations, in this study, we identified a novel B cell population termed 20(+)38(hi) B cells ( @entity2225 (+) @entity2731 (hi) @entity3053 (hi)) that spontaneously secretes Ab. At steady-state, 20(+)38(hi) B cells are distinct from PBs on the basis of @entity2225 expression, amount of Ab production, frequency of mutation, and diversity of BCR repertoire. However, cytokine treatment of 20(+)38(hi) B cells induces loss of @entity2225 and acquisition of @entity13221 , suggesting that 20(+)38(hi) B cells are precursors to PBs or pre-PBs. We then evaluated similarities and differences among @entity2225 (+) @entity2731 (+) @entity3053 (lo/int) @entity12910 (+) @entity12950 cells, @entity2225 (+) @entity2731 (hi) @entity3053 (hi) 20(+)38(hi) B cells, @entity2225 (-) @entity2731 (hi) @entity3053 (hi) PBs, and @entity2225 (+) @entity2731 (+) @entity3053 (lo/int) @entity12910 (-) memory B cells. We found that @entity12950 cells differ from 20(+)38(hi) B cells and PBs in a number of ways, including Ag expression, morphological appearance, transcriptional profiling, Ab skewing, Ab repertoire, and secretory response to stimulation. In terms of gene expression, @entity12950 cells align more closely with memory B cells than with 20(+)38(hi) B cells or PBs, but differ in that memory B cells do not express Ab secretion-related genes. We found that @entity12950 cell Abs use Vh4-34, which is often associated with autoreactivity, 3- to 6-fold more often than other B cell populations. Along with selective production of IgM anti- @entity2945 , these data suggest that @entity1 @entity12950 cells might be preferentially selected for autoreactivity/natural specificity. In summary, our results indicate that @entity1 healthy adult peripheral blood at steady-state consists of three distinct ASC populations.
