PE anti-mouse B7-H4 (B7S1, B7X)

B7-H4 is a newly discovered B7 family member that negatively regulates T cell immunity by inhibiting of T cell proliferation, cytokine production, and cell cycle progression. In vitro, B7-H4 inhibits CD4+ and CD8+ T cell proliferation, cytokine production, and generation of alloreactive cytotoxic T-cells (CTLs). In vivo, blockade of endogenous B7-H4 by specific monoclonal antibody promotes T cell responses. A new function of B7-H4 was reported as an important negative regulator of innate immunity through growth inhibition of neutrophils. It was reported that B7-H4 does not constitutively expressed on peripheral tissues but could be induced to express on T cells, B cells, macrophages, and dendritic cells. B7-H4 is expressed on some tumor cancer cells. The role of B7-H4 in tumor progression may be to transform precancerous cells and then protect them from immunosurveillance. Although B- and T- lymphocyte attenuator (BTLA) was proposed to be the receptor for B7-H4, further studies are needed to identify the inhibitory receptor of B7-H4.