Systematic characterization of porcine ileal Peyer's patch, II. A role for CD154 on T cells in the positive selection of immature porcine ileal Peyer's patch B cells.
We previously demonstrated that the majority (>/= 90%) of porcine ileal Peyer's patch (IPP) follicular cells are immature B cells destined to die by apoptosis, when incubated at 37 degrees. In this paper we approached the mechanisms responsible for positive selection of porcine IPP follicular immature B-cell selection, by screening for various cell types, cytokines and polyclonal and monoclonal antibodies for promoting the survival of IPP B cells. Of these reagents, only CD3 cross-linked purified T cells from mesenteric lymph nodes were able to rescue IPP follicular B cells from apoptosis, although polyclonal anti-IPP lymphocyte antibodies delayed apoptosis. This survival effect could be reproduced simply by incubating IPP follicular B cells with soluble and cell membrane-expressed CD154, an observation consistent with the demonstrated presence of CD40 and CD154 on porcine IPP follicular B cells and activated T cells, respectively. The IPP follicular B cells rescued in this manner expressed a more mature surface marker phenotype. Immunohistology and fluorescence-activated cell sorter analysis demonstrated that subpopulations of IPP follicular T cells (less than 0.5%) express CD154. Thus, perhaps unexpectedly, CD154 on T cells may play a role in the positive selection of immature B cells in the porcine IPP. The origin and control of the activated T cells identified within the porcine IPP remains to be investigated.
Andersen
J K
JK
Institute for Animal Health, Pirbright Laboratory, Pirbright, Working, Surrey, UK.
Takamatsu
H
H
Pullen
L
L
Parkhouse
R M
RM
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D019013:CD40 Antigens / Q000276:immunology; D023201:CD40 Ligand; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000502:physiology*; D010581:Peyer's Patches / Q000276:immunology*; D013552:Swine; D013601:T-Lymphocytes / Q000276:immunology*
D019013:CD40 Antigens; D008562:Membrane Glycoproteins; D023201:CD40 Ligand