T-CELLS, BUT NOT B-CELLS, ARE REQUIRED FOR BOWEL INFLAMMATION IN INTERLEUKIN 2-DEFICIENT MICE

Interleukin-2 (IL-2)-deficient (IL-2(-/-)) mice develop anemia and col onic inflammatory bowel disease. To elucidate the mechanism of this di sease, we have bred IL-2(-/-) mice to two strains of immunodeficient m ice, RAG-2-deficient (RAG-2(-/-), lacking B and T cells) and JH-defici ent mice (JH(-/-), lacking B cells). IL-2(-/-), RAG-2(-/-) double-muta nt mice are disease free, while IL-2(-/-), JH(-/-) double-mutant mice succumb to bowel disease at the same rate as IL-2(-/-) littermates. IL -2(-/-), JH(-/-) mice do not, however, succumb to anemia. Thus, sponta neous intestinal inflammation in IL-2(-/-) mice requires mature T cell s, not B cells, while anemia is dependent on B cells.