|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1992 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1991 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Function of cell surface 107kD glycoprotein(gp107) of stromal cells in lymphocyte development was investigated We have established two monoclonal antibodies (HANA-2 and HANA-5) against 107kD glycoprotein(s),and studied the expression and function of gp107 in hematopoietic system. In normal hematopoietic system, HANA-2 reacts only with fibroblastoid cells in the reticuloendothelia system, but not with lymphoid, myeloid and epithelial cells. On the other hand, HAHAN-5 reacts with activated lymphocytes and myeloid cells as well as established stromal cells. In the in vitro hematopoietic system, although HANA-5 strongly inhibited the development of both lymphoid and myeloid cells, HANA-2 inhibited only lymphoid development. HANA-2 but not HANA-5 could block the binding of lymphocytes with stromal cells, suggesting that HANA-2 reacts with an adhesion molecule on the stromal cells. By isolating cDNA clones for HANA-2 antigen, we identified it as an moue homologue of human vascular cell adhesion molecule, VCAM-1. This was further confirmed by the findings that antibodies against mouse VLA-4 strongly blocked lymphocye adhesion to stromal cells. HANA-5 has no blocking effects on cell adhesion and seems to be an activated antigen of both hamatopoietic and stromal cells, These results suggest an important role of VLA-4/VCAM-1 interaction in the development of lymphoid cells and that 107kD poteins on the stromal cell surface consist of at least two different molecules, one of which is VCAM-1.