background:
B7-H4 protein is expressed on the surface of a variety of immune cells and functions as a negative regulator of T cell responses. While B7-H4 mRNA is widely distributed in mouse and human peripheral tissues, cell surface expression of B7-H4 protein is limited and shows an inducible pattern on hematopoietic cells. Putative receptor of B7-H4 can be upregulated on activated T cells. By arresting cell cycle, B7-H4 ligation of T cells has a profound inhibitory effect on the growth, cytokine secretion, and development of cytotoxicity. Administration of B7-H4Ig into mice impairs antigen-specific T cell responses whereas blockade of endogenous B7-H4 by specific monoclonal antibody promotes T cell responses. B7-H4 thus may participate in negative regulation of cell-mediated immunity in peripheral tissues.
Function:
Negatively regulates T-cell-mediated immune response by inhibiting T-cell activation, proliferation, cytokine production and development of cytotoxicity. When expressed on the cell surface of tumor macrophages, plays an important role, together with regulatory T-cells (Treg), in the suppression of tumor-associated antigen-specific T-cell immunity. Involved in promoting epithelial cell transformation.
Subcellular Location:
cell membrane; Single-pass type I membrane protein (Potential). Note=Expressed at the cell surface. A soluble form has also been detected.
Tissue Specificity:
Overexpressed in breast, ovarian, endometrial, renal cell (RCC) and non-small-cell lung cancers (NSCLC). Expressed on activated T- and B-cells, monocytes and dendritic cells, but not expressed in most normal tissues (at protein level). Widely expressed, including in kidney, liver, lung, ovary, placenta, spleen and testis.
Post-translational modifications:
N-glycosylated.
Similarity:
Belongs to the immunoglobulin superfamily. BTN/MOG family.
Contains 2 Ig-like SLVtype (immunoglobulin-like) domains.
Database links:
Entrez Gene: 79679 Human
Entrez Gene: 242122 Mouse
Entrez Gene: 295322 Rat
Omim: 608162 Human
SwissProt: Q7Z7D3 Human
SwissProt: Q7TSP5 Mouse
SwissProt: Q501W4 Rat
Unigene: 546434 Human
Unigene: 137467 Mouse
Unigene: 160956 Rat
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
B7-H4(B7 Homolog 4)是B7家族中的新成员,它能通过抑制T细胞的增殖、细胞因子的产生和细胞周期的进程来负性调控T细胞的免疫应答,其大量表达B7-H4还可以促进上皮细胞的恶性转化,保护表皮细胞免于失巢凋亡,在肿瘤的发生,进展和转归中发挥重要作用.
目前对B7-H4信号通路的进一步的研究必将为自身免疫性疾病、病毒感染性疾病和器官移植后排斥反应中T细胞介导的免疫应答调控提供了新的途径,同时也为肿瘤的诊断、治疗提供崭新的前景。
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