Stimulation and proliferation of CD4+peripheral blood T lymphocytes induced by an anti‐CD4 monoclonal antibody

摘要

AbstractThere is experimental evidence that the CD4 molecule participates in the antigen‐driven activation of T cells expressing this surface glycoprotein. Whether CD4, a member of the immunoglobulin supergene family, acts as a ligand‐binding molecule and/or is directly involved in the activation pathway has yet to be established. In this study, we show that human CD4+lymphocytes can be activated by exposure to the anti‐CD4 monoclonal antibody (mAb) B66. Normal peripheral blood CD4+cells were induced to proliferate and to synthesize interleukin 2 (IL2) by the antibody. The specificity of the antibody stimulatory activity was tested by using IL2‐producing clones bearing either CD4 or CD8 on their surface. IL2 production was induced by mAb B66 in CD4+, but not CD8+, clones, whereas both types of clones responded to stimulation by the anti‐CD3 mAb Leu‐4. Despite its unique stimulatory activity, mAb B66 shared with other anti‐CD4 antibodies the ability to inhibit the specific cytolytic activity of CD4+effector cells. These results clearly indicate that cross‐linking of surface CD4 molecules with appropriate antibodies can fully activate CD4+lymphocytes. Whether the natural ligand for CD4 can trigger this activation pathway remain