title: Cloning and characterization of porcine 4Ig-B7-H3: a potent inhibitor of porcine T-cell activation.
abstract: BACKGROUND
  Members of the B7 superfamily costimulate the proliferation of lymphocytes during the initiation and maintenance of antigen-specific humoral and cell-mediated immune responses. B7-H3 (CD276) is a newly identified member of the B7 superfamily. It has been shown that B7-H3 plays a significant role in regulating T cell response in humans and mice, but it is not known whether a counterpart of human or murine B7-H3 exists in porcine species.
  
  
  RESULTS
  We cloned the porcine 4ig-b7-h3 gene using a blast search at the NCBI database with human b7-h3, RT-PCR and 3'-terminus RACE. Protein sequence analysis showed that the protein encoded by this gene contained 4Ig-like domains and was 90.88% identical with human 4Ig-B7-H3. Results of Dot-blot hybridization and RT-PCR showed that B7-H3 was broadly distributed in porcine tissues mainly as two isoforms, 2Ig-B7-H3 and 4Ig-B7-H3, of which 4Ig-B7-H3 was dominant. We further demonstrated that porcine 4Ig-B7-H3 was able to inhibit the proliferation and cytokine production of porcine T cells activated through the TCR pathway, similar to human B7-H3.
  
  
  CONCLUSIONS
  We cloned the porcine 4ig-b7-h3 gene and demonstrated that the porcine 4Ig-B7-H3 serves as a negative regulator for the T-cell immune response.
authors: Treatment and Research Center for Infectious Diseases, Beijing 302 Hospital, Beijing, China.
authors: Weiwei
authors: W
authors: Chen
authors: Zhibo
authors: Z
authors: Hou
authors: Chunman
authors: C
authors: Li
authors: Sheng
authors: S
authors: Xiong
authors: Henggui
authors: H
authors: Liu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D060887:B7 Antigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000276:immunology*; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013552:Swine; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*
chemical_list: D060887:B7 Antigens; D020033:Protein Isoforms