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Carol Riccardi, David W Pascual, Head and Neck Lymph Node (HNLN) B Cells from L-Selectin−/− (L-Sel−/−) Mice Show αE Expression Independent of Cholera Toxin (CT) Exposure (41.9), The Journal of Immunology, Volume 178, Issue 1_Supplement, April 2007, Page S31, https://doi.org/10.4049/jimmunol.178.Supp.41.9
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Abstract
Oral immunization with soluble protein plus adjuvant stimulates excellent regional, but not distal Ab responses. Although low level expression of distal immune B cells is observed, these wane with time. Studies examining homing receptor expression should provide insight into understanding how distal mucosal immunity is maintained. Studies showed that B lymphocyte trafficking in the HNLN and NALT is L-Sel-dependent. However, the absence of L-Sel enhanced distal B cell maintenance following oral CT immunization of L-Sel−/− mice and was partly compensated by increased αEβ7+ B cells, as evident by the significantly increased IgA antibody-forming cells (AFC) in L-Sel−/− nasal passages (NP) when compared to B6 NP. These IgA responses were supported by elevated HNLN IgA AFC responses (10- to 100-fold greater), and these AFC endured beyond 42 days, but not in B6 mice. To discern whether αEβ7 expression was influenced by CT directly, naive HNLN, mesenteric LN (MLN), and Peyer’s patches (PP) were isolated and stimulated in vitro with LPS, LPS + CT, Con A, or media. The mitogen-stimulated L-Sel−/− HNLN, MLN, and PP B cells showed early expression of αEβ7 at 48 hrs, but by 96 hrs, the L-Sel−/− HNLN clearly showed the greatest levels (30–35%) of αEβ7+ B cells. Both unstimulated and stimulated HNLN B cells showed similar levels of αEβ7 expression, and CT did not enhance αEβ7 expression. MLN and PP showed fewer (~10%) αEβ7+ B cells, and B6 B cells from each tissue showed <10% αEβ7+ B cells. These studies show that αEβ7 compensates for the absence of L-Sel on B cells, and these B cells are mostly derived from HNLN, and not from the gut.
Supported by NIH AI-55563.
