The Role of HLA-DR Antigens in PPD-stimulated Lymphocyte-Monocyte Interactions

Abstract

Autologous monocytes are required for an optimal lymphocyte proliferative response to purified protein deriative of tuberculin (PPD) in vitro and for a mixed lymphocyte culture induced by alloantigens. In the proliferative response to PPD autologous monocytes could be replaced with HLA-DR-compatible monocytes and partly with HLA-DR semi-identical. Despite a statistically significant difference between autlogous and HLA-DR disparate monocytes in their cooperative capacity with PPD-sitmulated lymphocytes, replacement in nearly 1/3 of the cases was possible. These findings were supported by more detailed studies in which increasing numbers of allogeneic and autologous monocytes were added to the isolated lymphocytes in the presence of PPD. The serologically defined HLA-DR antigens alone give insufficient information of the restriction elements controlling the PPD-stimulated lymphocyte-monocyte interactions.