Extrathymic Development of Self-Reactive γδ T Cells in Athymic BALB/cnu/nuMice

In the present report, we demonstrated that extrathymic gamma(delta) T cells proliferated in the mixed culture of lymph node cells of BALB/c nu/nu mice and irradiated syngeneic spleen cells (syngeneic MLR). Reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that V(delta)5 and V(delta)6 were dominantly expressed by the gamma(delta) T cells from the syngeneic MLR. Furthermore, the syngeneic MLR may expand V(delta)5+ T cells with BALB invariant delta (BID) sequence which is specifically detected in BALB background mice because V(delta)5 RT-PCR products from syngeneic MLR were digested with an AluI restriction enzyme which cut the D(delta)2-J(delta)1 junction of the BID sequence but not those of most non-BID V(delta)5 sequences. Interestingly, anti-mycobacterial and mammalian heat shock protein (Hsp) 60 mAb ML30 suppressed the generation of V(delta)5 with an AluI site in syngeneic MLR. These results suggest that extrathymically derived V(delta)5+ and V(delta)6+ gamma(delta) T cells recognize BALB/c self antigens and that the Hsp60 or an Hsp60-related molecule may be involved in the anti-self response of V(delta)5+ BID+ gamma(delta) T cells.