ACCELERATED INFLAMMATORY BOWEL-DISEASE OF TCR-ALPHA-DEFICIENT MICE PERSISTENTLY INFECTED WITH CRYPTOSPORIDIUM-PARVUM

TCR-alpha-deficient mice spontaneously develop inflammatory bowel dise ase (IBD) at 8-9 mo old. This study characterizes an accelerated form of IBD induced by Cryptosporidium parvum infection. Cryptosporidium pa rvum-infected TCR-alpha-deficient mice developed IBD as early as 4 wk old when challenged at 1 wk old. The lesions of this accelerated IBD r esembled the lesions of spontaneous IBD in TCR-alpha-deficient mice an d consisted of a mononuclear cell infiltrate within the intestinal lam ina propria and an increased proliferation of enterocytes. The mononuc lear cells within the lamina propria consisted of B cells and gamma de lta T cells. The distal ileum, cecum, and colon were grossly thickened due to a hyperplastic mucosa and edematous submucosa. The mechanism b y which C. parvum infection accelerates development of LED is presentl y unclear.