Functional characteristics of Peyer's patch lymphoid cells. IV. Effect of antigen feeding on the frequency of antigen-specific B cells.

The frequency of B cells in Peyer's patches from normal BDF(1) and sheep red blood cell (SRBC)-fed BDF(1) mice that could respond to antigenic determinants on SRBC and trinitrophenyl (TNP) was determined using an in vitro system of limiting dilution analysis. In normal mice, one B cell in 1.9 x 10(4) Peyer's patch cells could be induced to an anti-SRBC response and one B cell in 3.6 x 10(4) Peyer's patch cells could be induced to an anti-TNP response. The frequency of B cells capable of responding to SRBC in normal mice was similar in Peyer's patches and spleen. However, after feeding mice SRBC for 3 weeks, there was a 6-fold reduction in the frequency of B cells in Peyer's patches capable of responding to SRBC but no change in the frequency of B cells capable of responding to TNP. The average clone size of Peyer's patch B cells responding to SRBC was similar in normal and SRBC-fed mice. Although antigen-feeding does not stimulate Peyer's patch B cells in situ to humoral antibody synthesis, antigen-feeding can markedly alter the reactivity of the antigen-sensitive cell population in Peyer's patches. We previously demonstrated that T cells in Peyer's patches could be specifically carrier primed for helper function by SRBC feeding. We have now demonstrated that antigen-feeding reduced significantly the frequency of B cells in Peyer's patches capable of responding to the fed antigen. Peyer's patches appear to serve an important function as a sampling site for intestinal antigens.