Immunoglobulin leakiness in scid mice with CD4+ T-cell-induced chronic colitis

Inflammatory bowel disease in scid mice is initiated by transplantation of CD4(+) T-cells from immunocompetent syngenic donor mice. As the disease pro gresses, immunoglobulin (Ig)-containing cells appear in the gut lamina prop ria, suggesting that locally accumulating Ig may play a role in disease dev elopment. In the present work. we have investigated the relationship betwee n disease progression and patterns or levels of Ig isotypes in the feces of scid mice suffering from an ongoing colitis. The data clearly showed that the severity or progression of the disease did not influence the levels of IgA, IgG1, IgG2a, IgG2b, and IgG3, whereas the level of fecal IgM increased during the course of colitis. The presence of the serum protein alpha-1-an titrypsin in fecal extracts from diseased mice suggests that some of the fe cal Ig has leaked through the inflamed epithelial membrane into the gut lum en. Finally, Ig-containing cells were observed in mesenteric lymph nodes an d in the spleen, suggesting that the fecal Ig is produced both systemically and locally in the gut wall. In conclusion, the present results demonstrat e that the level of IgM increases as colitis progresses. Also, the five rem aining major Ig isotypes are increased in the gut lumen of scid mice with c olitis, but the individual Ig types vary randomly during the course of the disease. Thus, it is unlikely that immunoglobulins are involved in the immu nopathogenesis of this model of colitis. (C) 2000 Academic Press.