IMMUNE OR NORMAL GAMMA-DELTA T-CELLS THAT ASSIST ALPHA-BETA T-CELLS IN ELICITATION OF CONTACT SENSITIVITY PREFERENTIALLY USE V-GAMMA-5 AND V-DELTA-4 VARIABLE REGION GENE SEGMENTS

In the current study, we confirmed previous findings suggesting that g amma delta T cells were involved in the successful adoptive cell trans fer of contact sensitivity (CS) by alpha beta CS-effector T cells. In this study, we used hamster anti-mouse gamma delta-TCR mAb treatment o f CS-effector T cells, followed by enrichment and removal of the gamma delta T cells with goat anti-hamster Ig-linked magnetic beads, or by addition of hemolytic rabbit C. This removal of gamma delta T cells ab rogated adoptive cell transfers of CS, despite the presence of alpha b eta T tells that are known to mediate CS. FACS analysis documented enr ichment of gamma delta T cells rising from 1 to 2% of the starting cel ls, to 60 to 95% of the magnetic bead adherent cells, Adoptive cell tr ansfer of CS was reconstituted by adding back to the alpha beta cells, highly enriched gamma delta cells attached to anti-gamma delta-TCR ma gnetic beads. Not only were gamma delta-enriched T cells from sensitiz ed mice able to assist immune CS-effector alpha beta T cells, but gamm a delta T cells from normal nonimmune mice also had CS-assisting activ ity, and furthermore, neither were MHC-restricted in this function. Th us, CS-assisting gamma delta T cells were present endogenously in norm al mice without prior immunization, and acted without Ag specificity a nd without MHC restriction, to assist CS-effector alpha beta T cells. Similar studies, with hamster mAbs specific for V gamma and V delta po rtions of gamma delta-TCR, demonstrated that the gamma delta T cells t hat assisted the CS-effector alpha beta T cells preferentially express ed V gamma 5 and V delta 4 in their TCR, PCR analysis on extracted mRN A showed that V gamma 5 and V delta 4 gene segments indeed were rearra nged and expressed in the sensitized and normal lymph nodes; and one- and two-color FACS analysis of magnetic bead-fractionated cells sugges ted that V gamma 5 and V delta 4 were expressed on the same T cells. i n summary, these results demonstrated that V gamma 5(+), V delta 4(+), gamma delta T cells were needed to assist alpha beta effector T cells in the adoptive cell transfer of CS.