Preparation Of A Mouse Anti-human 2IgB7-H3 Monoclonal Antibody And Study Of Its Biological Functions

B7-H3 is a newly indentified member of the B7 superfamily and is a type of I membrane protein of about 45-110kDa encoding 316-534Aa.Similar to other B7 homologs, B7-H3 mRNA was dectected on a broad spectrum of tissues . It can also be highly expressed on many kinds of tumour cells.The receptor for B7-H3 was unknown until now.It is reported that B7-H3 has two completely opposite effects on T cells. One is inducing T Lymphocytes activation,the other is inhibitating T cells proliferation. B7-H3 as a positive costimulatory molecule can stimulate the proliferation of T cells and selectively enhance IFN-γsecretion and CTL activity.However,other researchers also demostrated an inhibitory function on the proliferation of CD4+ T cell and IFN-γsecrection. B7-H3 has extracellular IgV- and IgC-like domains which is typical of B7 family members(2IgB7-H3) and a new isoform consistant with a dual IgV-IgC domain in human B7-H3(4Ig-B7-H3, B7-H3b). The difference of expression and potential biological functions of them are worth deeply researching. It is well accepted that B7-H3 signal pathway plays an important role in the regulation of inflammatory responese,in the prevention of transplation rejection and tumour development, as well as in the modulation of autoimmune diseases . The mouseanti-human 4IgB7-H3 mAb and 2IgB7-H3 21D4 has been already made in . Therefore, the specific 2IgB7-H3 mAb agaist B7-H3 molecule, a valueable tool for modulation B7-H3 signal pathway, not only provides a new perspective of a thoroughly understanding of the delicate regulation of the immune system, but also plays a potential role in clinical applications.