ANIMAL-MODELS OF COLITIS

In 1994 the greatest progress in the development of animal models of human inflammatory bowel disease occurred in the characterization of the roles of specific subsets of immune cells and specific microbial agents in colitis. The reconstitution of scid mice with specific subsets of CD4(+) lymphocytes causes colitis, a finding that has underscored the potential importance of balance between T-helper 1 and 2 lymphocyte subsets as a determining factor in the development of colitis. The demonstration that the germ-free state prevents development of gut and joint inflammatory disease in HLA-B27 transgenic rats suggests that reconstitution of germ-free animals with specific bacterial strains may provide an approach to determine the differential effect of specific bacteria on the development of inflammation in animal models of colitis.