Murine M290 integrin expression modulated by mast cell activation

Intraepithelial T lymphocytes possess a (TGFP)-inducible integrin complex that consists of the β7 integrin chain in association with a novel a chain, murine αM290. Using antibodies directed against the murine αM290 chain, IL-3-dependent murine bone marrowderived mast cells demonstrated positive staining after induction with TGFβ. Sequence information from the human intraepithelial T lymphocyte-αE gene sequence was used to clone the murine homolog from a TGFβ-induced T cell library. The murine αE homolog gene encodes a protein recognized by antibodies to αM290. Expression of this gene by bone marrowderived mast cells was found to be induced by TGFβ or IgE-mediated cross-linking of FcϵR1. Furthermore, exposure of murine TK-1 cells to supernatants from activated mast cells induces the expression of the αM290 gene, indicating that a mast cell mediator(s) can act in a paracrine manner to induce expression of this integrin complex by other cells.