Jα-gene segment usage and the CDR3 diversity of porcine TCRα-chain cDNA clones from the PBL of a five-month-old pig and the thymus of a one-month-old pig

Porcine T-cell receptor α (TCRα)-chain cDNA clones were isolated from libraries made from two different sources, the thymus of a 1-month-old LW strain pig and the peripheral blood lymphocytes (PBL) of a 5-month-old Clawn strain pig. Among 109 cDNA clones with the Jα-gene segment, 44 different Jα-gene segments were found out of the 61 Jα-gene segments previously identified in the porcine germline sequence. Among the 103 complete TCRα-chain cDNA clones with the rearranged Vα- and Jα-gene segments, 33 different Vα-gene segments were identified, which randomly rearranged to Jα-gene segments indicating lack of any specific combinations between Vα- and Jα-gene segments with only one exception of the same set of Jα-gene segments in duplicate clones. Among the cDNA clones from PBL of an individual 5-month-old Clawn strain pig, a broad distribution of the Jα-gene segment usage was observed over the entire Jα-gene cluster. The Jα-gene segment usage in an individual 1-month-old thymus from a LW strain pig also gave a pattern consistent with the 5-month-old pig. These distributions of the Jα-gene segment usage were similar to the previously reported patterns for human T-cells and those of adult murine T-cells. Among the porcine cDNA clones isolated, TCRα-chain CDR3 length ranged from 4 to 14 amino acids with the average being 9.35 amino acids. Present report provides groundwork for further studies on porcine TCRα-chain expression.