Visualization of human helper T lymphocyte differentiation antigen in primate brain.

The differentiation antigen T4 is present on the helper/inducer subset of T cells. In the acquired immune deficiency syndrome (AIDS), this lymphocyte subset is selectively depleted by HTLV-III/LAV virus which apparently uses the T4 antigen as a viral receptor. The autoradiographic visualization of the T4 antigen on sections of squirrel monkey brain shown here reveals a heterogeneous pattern with clustering in the same emotion-mediating regions of the brain that are usually enriched with neuropeptide receptors. Immunoprecipitates of cell membranes from primate brain indicate that an antigen very similar to T4 is present on brain and T4+ T lymphocytes. Since patients with AIDS frequently develop complications of the central nervous system and HTLV-III/LAV sequences have been found in the brain, these data suggest that direct infection of some brain cells with HTLV-III/LAV occurs via a mechanism involving the T4 antigen complex similar to that proposed for lymphocyte infection. In view of the brain sites found to express the T4-like antigen, the behavioral changes and mood shifts observed in AIDS patients may result from localized viral replication.