In order to determine the role of Peyeros patch lymphocytes (PPL) in self-clearing of Cryptosporidium parvum
infection in murine models, changes in PPL subsets, their
cytokine expression, and in vitro
IgG1 and
IgA secretions by PPL were observed in primary- and challenge-infected C57BL/6 mice. In primary-infected mice, the percentages of CD4+ T cells, CD8+ T cells, sIgA+ B cells, IL-2+ T cells, and IFN-gamma+ T cells among the PPL, increased significantly (P < 0.05) on day 10 post-
infection (PI). Secretion of
IgG1 and
IgA in vitro by PPL also increased on day 10 PI. However, all these responses, with the exception of
IgG1 and
IgA secretions, decreased in challenge-infected mice on day 7 post-challenge (= day 13 PI); their
IgG1 and
IgA levels were higher (P > 0.05) than those in primaryinfected mice. The results suggest that murine PPL play an important role in self-clearing of primary C. parvum
infections through proliferation of CD4+, CD8+, IL-2+, and IFN-gamma+ T cells, and
IgG1 and
IgA-secreting B cells. In challenge
infections, the role of T cells is reduced whereas that of B cells secreting
IgA appeared to be continuously important.