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. Methodology/principal findings: 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.
Conclusion
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.