The Study Of B7-H1 Expression In Leukemia Cells And Its Role Of Regulation On T Cells Immunity Responses

B7-H1 is a recently identified member of the B7 family molecules. Upon ligation to its receptors on T cells it regulates activation and differentiation of T cells. B7-H1 preferentially costimulates IL-10 production in resting T cells and further induces the apoptosis of activated T cells. PD-1 is a receptor of B7-H1 and is shown to mediate the inhibition of activated T cell response, presumably by inhibiting cell cycle progression. The expression of B7-H1 protein is limited to macrophage lineage of cells in normal tissues, although its mRNA transcription is found in a broad range of tissues. B7-H1 is abundant in various human cancers. The tumor-associated B7-H1 increases apoptosis of antigen specific T cells, leading to growth of immunogenic tumor growth in vivo. Current data suggest that B7-H1 regulates the organ -specific tolerance in normal tissue and may contribute to immune evasion by cancers. Little is known about its expression and regulation in leukemia now. We detected the expression of B7-H1 in the leukemia cells and initial explore the its role of regulation on T cell immune responses.We detected expression of B7-H1 using of SYBR Green I real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR), immunocytochemistry and western blot.(1) We investigated the expression of B7-H1 gene in a panal of 9 human hematopoietic cell lines and 2 tumor cell line. The BMMNCs from 74 initial leukemia patients (ALL 19 cases, AML 40 cases and CML 15 cases), 5 relapsed patients and 10 normal donors were detected using Real-time quantitative PCR for B7-H1 gene expression. Follow-up monitoring of B7-H1 expression in 12 patients acquired complete remission (CR) and was performed. The results showed that â‘  B7-H1 mRNA is abundant in all tested...