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

Summary Despite the potential for extensive diversity of γδ TCR, especially for δ‐chains, expression of the γδ TCR repertoire in various mouse epithelial tissues is highly restricted. This implies that the recognition of antigen by γδ T cells may also be limited. To date, however, few studies have examined γδ TCR diversity in peripheral lymphoid tissue. This report presents the Vδ usage and junctional region sequences of TCR δ‐chain transcripts derived from the lymph nodes of normal (PL/J × SJ/L) Fl mice. Rearranged TCR Vδ‐Cδ transcripts were amplified by PCR from TCR δ‐chain cDNA using oligonucieotide primers specific for the murine Vδl to Vγδ7 genes and the Cδ region. Following cloning of the polymerase chain reaction‐amplified TCR δ 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 Vδ3, all Vδ genes were expressed in mouse lymph node. Furthermore, predominant usage of Jδ1 was found in cDNA clones expressing Vδ2. Vδ4, Vδ5. Vδ6 and Vδ7 gene segments but despite this there was extensive junctional diversity of δ‐chains primarily due to the usage of multiple Dδ segments and N‐nucleotide sequence addition. In contrast, the Vδl cDNA clones had limited heterogeneity consisting mostly of Vδ1 directly spliced to γδ gene rearrangements. These results show that the expressed murine peripheral TCR δ‐chain repertoire is extremely diverse indicating that γδ T cells may potentially recognize a large number of antigens, and play an important role in contributing to host immune responses.