Lack of site of origin effects on distribution of IgA antibody-containing cells.

Previous experiments (Husband, 1982) indicated that IgA-specific antibody-containing cells (ACC), appearing among thoracic duct lymphocytes (TDL) following challenge of intestinal segments of i.p. primed rats, display antigen-dependent distribution in the small intestine by 12 hr after their i.v. injection into autologous recipients. Data are presented here which demonstrate that ACC among TDL collected from rats bearing double Thiry-Vella loops challenged with two different antigens still appear almost exclusively in loops immunized with the antigen corresponding to their antibody specificity, even when injected into recipients in which immunized loops were prepared from different levels of the small intestine to that of the donors. These experiments indicate that, in animals given whole gut priming (by i.p. immunization) and segmental challenge (by lumenal challenge of isolated loops), the site of origin of IgA-ACC precursors does not influence antigen-induced distribution patterns. To determine whether segmental priming followed by whole gut challenge results in site of origin effects, rats were primed by subserosal immunization of a single Peyer's patch, either in the proximal or distal intestine, and then challenged intraduodenally. The ultimate IgA-ACC distribution was similar, regardless of the site of priming. These results indicate that, in a model employing priming with antigen in Freund's complete adjuvant, there is no site of origin effect on ultimate IgA plasma cell location within the small intestine, whether whole gut priming and segmental challenge or segmental priming and whole gut challenge, are used.