Biotinylated B7-1 Protein

Quality Statement:
As the first identified B7 family member, CD80is widely expressed in a broad spectrum of tissues, even on some malignanttumor cells, thereby suggesting the potential mechanism of immune evasion oftumor cells.CD80 is recognized as one of the most potent costimulatorymolecules by which immune cells limit malignant growth. It is upregulated uponcell stress and it is critical for efficacious immune surveillance duringcarcinogenesis. Low surface expression of CD80 was reported as an immune escapemechanism of colon carcinoma; on the other hand, its expression resultedenhanced in high-frequency microsatellite instability (MSI) colorectal cancers,a CRC subtype which is highly immunogenic and associated with a betterprognosis. Both in vivo and in vitro studies showed that the upregulation ofCD80 on tumor cell surface successfully activates antitumor immune responses,while its expression is frequently lost during tumor progression probably dueto selective pressure by the immune system. Thus, to develop effectiveapproaches for cancer immunotherapy, strategies for enhancing CD80 expressionin tumors are urgently required.

Reference:
1.Carin C. Stamper, Yan Zhang, James F. Tobin,David V. Erbe, Shinji Ikemizu, Simon J. Davis, Mark L. Stahl, Jasbir Seehra,William S. Somers & Lidia Mosyak: Crystal structure of the B7-1/CTLA-4complex that inhibits human immune responses, Nature volume 410, pages608–611 (2001).