ENUMERATION OF SELECTED LEUKOCYTES IN THE SMALL-INTESTINE OF BALB C MICE INFECTED WITH CRYPTOSPORIDIUM-PARVUM/

Neonatal, suckling BALB/c mice inoculated with Cryptosporidium parvum produce an infection characterized by continuous shedding of oocysts t hat spontaneously clears by the time the animals are three weeks of ag e. Neonatal mice were used to characterize the leukocyte subgroups pre sent in Peyer's patches from the ileum and jejunum of Cryptosporidium- infected and healthy mice. After infection, ileal Peyer's patches show ed a predominant CD8+ response, with abundant monocytes-macrophages (M OMA-2+) and nonlymphoid dendritic cells (NLDC-145+ cells). In contrast , jejunal Peyer's patches showed more T lymphocytes than ileal patches , with a predominance of CD4+ cells and many dendritic NLDC-145+ cells and MOMA-2+ cells. The present results showed that ileal and jejunal Peyer's patches are functionally different in response to Cryptosporid ium parasites. These findings suggest a preferential involvement of je junal Peyer's patches in T cell-dependent immunity against the parasit e, whereas ileal patches may be associated with B cell expansion and m aturation.