Expression of the T cell receptor δ-chain repertoire in mouse lymph node

Despite the potential for extensive diversity of gamma delta TCR, especially for delta-chains, expression of the gamma delta TCR repertoire in various mouse epithelial tissues is highly restricted. This implies that the recognition of antigen by gamma delta T cells may also be limited. To date, however, few studies have examined gamma delta TCR diversity in peripheral lymphoid tissue. This report presents the V delta usage and junctional region sequences of TCR delta-chain transcripts derived from the lymph nodes of normal (PL/J x SJ/L) F1 mice. Rearranged TCR V delta-C delta transcripts were amplified by PCR for TCR delta-chain cDNA using oligonucleotide primers specific for the murine V delta 1 to V delta 7 genes and the C delta region. Following cloning of the polymerase chain reaction-amplified TCR delta cDNA, the extent of junctional diversity was assessed by nucleotide sequencing of the V-D-J junctions of individual TCR cDNA clones. With the exception of V delta 3, all V delta genes were expressed in mouse lymph node. Furthermore, predominant usage of J delta 1 was found in cDNA clones expressing V delta 2, V delta 4, V delta 5, V delta 6 and V delta 7 gene segments but despite this there was extensive junctional diversity of delta-chains primarily due to the usage of multiple D delta segments and N-nucleotide sequence addition. In contrast, the V delta 1 cDNA clones had limited heterogeneity consisting mostly of V delta 1 directly spliced to C delta gene rearrangements. These results show that the expressed murine peripheral TCR delta-chain repertoire is extremely diverse indicating that gamma delta T cells may potentially recognize a large number of antigens, and play an important role in contributing to host immune responses.