Expression of beta 7 integrins and other cell adhesion molecules on mouse lymphocytes and their modulation by a new cytokine, IL-2 receptor-inducing factor.

We explored the role of a new cytokine, IL-2 receptor-inducing factor (IL-2RIF), in intestinal mucosal immunity and in the regulation of integrin beta 7 receptors on intestinal lymphocytes. Most SIEL (small intestine intraepithelial lymphocytes) were M290 (alpha M290 beta 7) positive, while only 10 to 15% of SIEL were R1-2 (alpha 4) positive. The expression of alpha 4 (R1-2) and beta 7 (M293) but not alpha M290 beta 7 integrin on SIEL was up-regulated by IL-2RIF. Incubating SIEL with IL-2RIF resulted in the up-regulation of CD45RB and down-regulation of CD44. About 50% of LPL (lamina propria lymphocytes) were alpha M290 beta 7 positive, while only 20% of LPL were alpha 4 positive. The expression of alpha M290 beta 7 integrin on LPL was down-regulated and alpha 4 and beta 7 integrin was up-regulated by IL-2RIF. Incubating LPL with IL-2RIF resulted in the up-regulation of CD44 and no significant change of CD11a, CD45, CD45RB, and ICAM-1. These results suggested that SIEL and LPL may play a different role in intestinal mucosal immunity and that IL-2RIF may play an important role in regulating the functions of integrins beta 7 on IEL and LPL.