Requirement for CD4+T Cells in the γδ T Cell Proliferative Response to Daudi Burkitt's Lymphoma

Abstract

Daudi Burkitt's lymphoma cells stimulate the proliferation of Vγ2 Vδ2 T cells in human peripheral blood mononuclear cells (PBMC). Transfection studies have established that the γδ T cell receptor is sufficient for recognition of a ligand associated with Daudi cells. Since other studies have demonstrated the need for cooperation between αβ T cells and Vγ2 Vδ2 T cells in the proliferative response to mycobacterial antigens, we used human, unfractionated PBMC and PBMC depleted of specific T cell subsets to determine whether the γδ T cell response to Daudi cells also requires cooperation between αβ and γδ T cells. In the current study, we demonstrate that depletion of CD4+T cells substantially reduces the overall proliferative response of PBMC to Daudi cells and subsequent γδ T cell expansion. IL-2 production by PBMC in response to Daudi cells was also decreased by depletion of CD4+T cells, but not by depletion of CD8+or γδ T cells. In the CD4+T-cell-depleted PBMC, proliferation in response to Daudi cells was restored by the addition of IL-2. These data stress the importance of cooperation between αβ and γδ T cells in the response to some complex antigens.