Comparative distribution of immunoglobulin-containing cells in stomach, intestine and associated lymph nodes of cattle.

Immunoglobulin (Ig)-containing cells were investigated immunohistochemically in the stomach, intestine and associated lymph nodes of clinically normal calves, cows and fetuses to examine mucosal immune responses in the forestomach to rumen microbial flora. IgG-containing cells were observed in the mucosal propria of the forestomach of a 32 day-old, a 37 day-old, two 90 day-old calves, and of all 5 cases of cows. However, no IgA- and IgM-containing cells were observed. Further, no Ig-containing cells were detected in the associated lymph nodes of all calves and cows. Various numbers of Ig-containing cells, predominantly IgG, were observed in the mucosal propria of the abomasum, small intestine and cecum, and in the mesenteric lymph nodes of aged calves and all cows. No Ig-containing cells were observed in any tissues of fetuses. The results suggest that the development of mucosal immune responses in the forestomach may be incomplete as compared with that of the intestine.