BIAS IN THE GAMMA-DELTA T-CELL RESPONSE TO LISTERIA-MONOCYTOGENES - V-DELTA-6.3(-DELTA T-CELL RESPONSE TO LISTERIA-MONOCYTOGENES() CELLS ARE A MAJOR COMPONENT OF THE GAMMA)

Despite extensive research, the role that gamma delta T cells play in the immune response to infectious disease has yet to be established, H ere we report the generation of a mAb specific for the V delta 6.3 TCR and investigate the gamma delta(+) and V delta 6.3(+) T cell response s to the intracellular bacterium Listeria monocytogenes in BALB/c mice . By infecting animals with various doses of Listeria and analyzing th e components of the cellular immune response at the two primary sites of infection, the liver and spleen, we have shown that the kinetics, c omposition, and magnitude of the gamma delta and V delta 6.3 T cell re sponses are dependent upon the injected dose of bacteria and the organ in which the infection is established, At low doses of infection, the gamma delta T cell response occurs late in the disease course, while at high doses, the response is earlier and of greater magnitude, parti cularly in the liver, At all infectious doses and in both tissues, the V delta 6.3(+) population predominates and together with V delta 4(+) cells composes the bulk of the gamma delta T cell response. Changes i n the morphology of gamma delta(+) and V delta 6.3(+) cells at the sit e of infection are consistent with cellular activation and suggest tha t these cells are active participants in the Listeria-induced immune r esponse, The results of our study suggest that many features of the ga mma delta T cell response to Listeria are dose and tissue related.