HLA‐D/DR Restriction of Macrophage‐dependent Antigen Activation of Immune T Lymphocytes: Cross‐reacting Allogeneic HLA‐D/DR May Partly Substitute for Self HLA‐D/DR

Abstract

Optimal proliferative response of [human] T [thymus-derived] lymphocytes to purified protein derivative of tuberculin (PPD) in vitro requires that antigen be presented by autologous macrophages or allogeneic macrophages sharing HLA-D/DR determinants with the T cell donor. In some cases, T cells may respond to a limited extent to PPD in association with macrophages expressing different HLA-D/DR determinants. Various combinations of T cells and HLA-D/DR disparate macrophages were stimulated with PPD. A stronger PPD-specific response was found in HLA-D/DR-incompatible combinations in which the macrophages carried HLA-DR antigens known from serological studies to be cross-reactive with those of the T cell donor than in combinations in which this was not the case. The cross-reactions detected by serology may sometimes be reflected on a functional level in T lymphocyte/macrophage cooperation.