Peritoneal B‐2 cells comprise a distinct B‐2 cell population with B‐1b‐like characteristics

Abstract

B‐1 and B‐2 cells are lymphocyte populations that differ in development, surface marker expression, tissue localization, and function. Though mainly found in the spleen, lymph nodes, and circulation of mice, small numbers of B‐2 cells are found in the peritoneal cavity, a site predominantly populated by B‐1 cells. Here, we characterized peritoneal B‐2 cells, and determined their relationship to B‐1 cells. We found that peritoneal B‐2 cells appear to be intermediate between splenic B‐2 and peritoneal B‐1 cells in terms of surface marker expression of B220, CD80, and CD43, expression of several marker genes, and in vitro viability and IgM secretion. Adoptive transfer of peritoneal B‐2 cells into severe combined immunodeficiency mice resulted in the acquisition of a phenotype reminiscent of B‐1b cells, as shown by up‐regulation of Mac‐1 and CD43, and down‐regulation of CD23. Moreover, adoptively transferred peritoneal B‐2 cells recapitulated B‐1 cell function by producing natural IgM in recipient mice. These data suggest that peritoneal B‐2 cells express some characteristics of B‐1b cells and that this similarity increases with additional time in the peritoneal cavity.

Reciprocal generation of Th1/Th17 and Treg cells by B1 and B2 B cells

“…B2p cells fell in between in both measurements (Fig. 1A, B), in keeping with previous work [17]. The same hierarchy of APC function was also observed in mixed lymphocyte reactions (MLR) ( [15] and Zhong, unpublished data).…”

“…Recently, we also reported that B2 cells in the peritoneal cavity (B2p) differ from both B1p and B2s cells and express many characteristics at levels intermediate between the two [17]. We first investigated the relative capacity of these B cell subsets in presenting OVA peptide to OVA-responsive transgenic T cells.…”

“…B1p and B2p cells were prepared from peritoneal washouts as previously described [17] and sorted as B220 low CD5 + and B220 hi CD5 -cells, respectively. B2s cells were either sorted as B220 hi CD5 -CD4 -CD8 -cells or purified using MACS negative selection beads (Miltenyi Biotec).…”

TLR Agonists Selectively Promote Terminal Plasma Cell Differentiation of B Cell Subsets Specialized in Thymus-Independent Responses

“…Based on the ELISPOT data, we estimate that this Ig-secreting subcompartment constitutes ϳ1% of the B-1 and MZ populations. It has recently been shown that peritoneal B-2 cells express some B-1b cell-like features (17), thus suggesting that the B cell functional attributes could also be shaped by the anatomical microenvironment. Our present data show that, despite these similarities, peritoneal B-2 cells behave like splenic FO B cells in response to TLR agonists.…”

Enhanced trafficking to the pancreatic lymph nodes and auto-antigen presentation capacity distinguishes peritoneal B lymphocytes in non-obese diabetic mice

“…However, peritoneal B2 cells appear to constitute a unique B cell subset, which exhibits characteristics that are intermediate between peritoneal B1 cells and splenic B2 cells. Peritoneal B2 cells additionally acquire certain characteristics of B1 B cells upon residing in the peritoneal cavity [25]. CD11b, moreover, has been suggested to distinguish different developmental stages of peritoneal B cells [26] and its expression depends upon the location within the peritoneal cavity [27].…”