Contribution of the SgIGSF adhesion molecule to survival of cultured mast cells in vivo.

Spermatogenic immunoglobulin superfamily (SgIGSF) is a recently identified adhesion molecule, and the microphthalmia transcription factor (MITF) was essential for its expression in mast cells. Since the tg mutant allele is practically a null mutation of the MITF gene, cultured mast cells (CMCs) derived from (WBxC57BL/6)F(1) (F(1))-tg/tg mice did not express SgIGSF whereas CMCs from F(1)-wild-type (+/+) mice expressed it abundantly. When cocultured with NIH/3T3 fibroblasts, F(1)-tg/tg CMCs showed poor adhesion to NIH/3T3 fibroblasts. When injected intraperitoneally, F(1)-tg/tg CMCs showed poor survival in the peritoneal cavity of mast cell-deficient F(1)-W/Wv mice. SgIGSF was expressed in tg/tg CMCs ectopically through retroviral transfection and through expression of a transgene. The resulting tg/tg CMCs showed not only a better adhesion to NIH/3T3 fibroblasts but also a better survival in the peritoneal cavity than control F(1)-tg/tg CMCs. SgIGSF-mediated adhesion seemed to play a role in the survival of CMCs in the peritoneal cavity.