Negative signaling by surface IgM on B cells isolated from ileal Peyer's patch follicles of sheep.
Lymphoid follicles from the sheep ileal Peyer's patch (PP) were used to prepare a cell suspension consisting of 98% surface IgM-positive (sIgM+) B cells and 1% T cells. Co-stimulation of follicular cells with pokeweed mitogen and either recombinant bovine interleukin 1 (IL 1) or IL 2 resulted in a marked proliferative response. In contrast, the addition of soluble F(ab')2 rabbit anti-sheep Ig completely inhibited the proliferative response induced by pokeweed mitogen and IL 1 or IL 2 co-stimulation. Anti-Ig inhibition of B cell proliferation was specific for ileal PP follicular cells and was not observed with mesenteric lymph node cells or splenocytes. Furthermore, suppression of ileal PP follicular B cell proliferation required at most divalent cross-linking of sIg was independent of Fc receptors, but was dependent on the concentration of anti-Ig and required 48 h for maximal effect. Negative signaling by sIgM indicates that ileal PP follicular B cells are functionally distinct from B cells in other secondary lymphoid tissues. Also, the present observations are consistent with previous reports indicating that B cell proliferation in ileal PP follicles is antigen independent.
Griebel
P J
PJ
Department of Medical Physiology, University of Calgary, Alberta, Canada.
Davis
W C
WC
Reynolds
J D
JD
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D001402:B-Lymphocytes / Q000166:cytology*; D002450:Cell Communication / Q000502:physiology*; D002454:Cell Differentiation / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D002478:Cells, Cultured; D007082:Ileum / Q000276:immunology; D007075:Immunoglobulin M / Q000502:physiology*; D066298:In Vitro Techniques; D007583:Jejunum / Q000276:immunology; D010581:Peyer's Patches / Q000276:immunology*; D012756:Sheep; D015398:Signal Transduction; D013154:Spleen / Q000276:immunology
D000888:Antibodies, Anti-Idiotypic; D007075:Immunoglobulin M