Common TCR Vd5 CDR3 rearrangement in T cells infiltrating mouse skin allograft

GY Zhang, M Hu, JF Knight and S Alexander
The Centre for Kidney Research, Children’s Hospital, Westmead, NSW 2145

Gamma/delta T cells represent 0.5-10% of the total peripheral T cell pool and are thought to contribute to immune defence and regulation. To investigate the possible involvement of gamma/delta T lymphocytes in the immune response to allografts, we analysed TCR Vd repertoire by RT -PCR in a mouse skin allograft model. B6(H-2b) mice were grafted with tail skin from bm1( H-2bm1) (n=4)or B10.BR ( H-2k) (n=4) mice in two groups. Both groups showed Vd 5 and Vd7 were expressed by graft infiltrating T cells by RT-PCR. Spectratyping of Vd5 from grafts and spleens of grafted mice revealed a dominant common size peak across 8 different animals. Vd5 from the spleens of naïve mice showed a more diverse spectratype pattern. In contrast, Vd4 and 7 showed multiple peaks. DNA sequencing of Vd5 revealed the existence of a common CDR3 and also similar CDR3 motifs used by graft infiltrating T cells in all 8 mice. CDR3 sequences of Vd5 from spleens of grafted mice and naïve mouse were more diverse but occasional similar clones were seen. This data demonstrates a restricted TCR Vd5 usage by graft infiltrating T cells. The presence of common CDR3 rearrangements and similar motifs used by the B6 host gamma/delta T lymphocytes in allografts of differing H-2 type suggest a common ligand or ligands exists and that this activation occurs as part of the transplant process.

Presented at the 20th Annual Scientific Meeting of the Transplantation Society of Australia and New Zealand. April 2002, Canberra

Correspondence
Geoff Zhang
Centre for Kidney Research
The Children’s Hospital at Westmead
Locked Bag 4001
Westmead NSW 2145 Sydney Australia
Tel: +61 2 9845 3106
Email1:Geoff Zhang