Immune responses in intestinal tissue to particulate antigens. Development of cells forming different classes of antibody in primary and secondary responses.

Abstract

SummaryCharacteristics of primary and secondary immune responses resulting from antigenic stimulation via the intestinal epithelium have been examined by enumerating rosette‐forming cells synthesizing IgM, IgG and IgA antibodies. These cells arise in local and peripheral lymphoid tissues in both responses. In general terms, the primary response of mesenteric lymph nodes following intestinal antigenic stimulation is similar to that observed in the spleen or other lymph nodes when antigen is given parenterally, showing the characteristic change from IgM to IgG antibody formation. In the intestinal submucosa and lamina propria IgA‐rosette‐forming cells are most numerous but a significant IgG response also occurs. IgG rosette‐forming cells also appear in the spleen following immunization via the intestinal route.This route of immunization primes animals to respond to later antigenic stimulation given either via the intestine or parenterally: the primed state lasts at least for 14 weeks. The greatest secondary response occurs in the mesenteric lymph nodes where IgM rosette‐forming cells predominate. In the intestinal lamina propria and submucosa the IgM rosette‐forming cells secondary response is substantially greater than that of IgG‐ and IgA‐rosette‐forming cells. Priming via the intestinal route leads to a significant IgA‐rosette‐forming cells response in the spleen, irrespective of whether the second injection is given intestinally or intravenously.