Characterization of T-cell-receptor gamma (TRG) gene rearrangements in alloreactive T-cell clones.

Rearrangements of the T-cell Rearranging Gene (TRG) or T-cell-receptor gamma-chain genes were analyzed in 24 in vivo-sensitized alloreactive T-cell clones. This analysis represents the first complete assignment of TRG gene rearrangements to given variable and joining gene segments in nonleukemic T cells and provides some evidence for the hypothesis of sequential gamma genes rearrangements during T-lymphocyte differentiation. TRG gene rearrangements in our T-cell panel involved the known "active" V gamma genes, with a preferential use of V2 and V4 genes. In most clones, rearrangements occurred on both chromosomes and involved the J2 segment, but only 2 and 4 out of the 49 described rearrangements involved the additional J gamma segments JP1 and JP2, respectively. Two peculiar rearrangements were found. The first one was probably due to the creation of a new restriction enzyme site in the N-region at the V-J junction; the second can be explained by an aberrant rearrangement of a V gene to a sequence located between exons 2 and 3 of the TRGC1 gene.