• mice exhibit inflammatory infiltrate in the lamina propria, neutrophil infiltration of the crypt and surface epithelium, and epithelial injury with surface denudations and ulcerations associated with crypt loss and epithelial mucodepletion
• by 4 weeks of age, mice develop highly penetrant and severe colitis unlike wild-type or single homozygous mice that increases in severity over time
• at 8 weeks, mice exhibit marked inflammation and colonic thickening unlike Rag2tm1Fwa homozygotes
• however, treatment with anti-TNF-alpha antibodies, T regulatory cells, or broad spectrum antibiotics restores normal colon phenotype, and treatment with broad spectrum antibiotics prevents communication of colitis to offspring
• female mice cross-fostering wild-type mice and Rag2tm1Fwa homozygotes fail to establish normal resistance to colitis in cross-fostered pups and mice can transmit susceptibility to colitis to wild-type mice housemates