Lack of Leu-3a epitope on T-helper (CD4) lymphocytes.

Human T-helper cells express membrane-bound CD4 antigen whose many epitopes are recognized by different monoclonal antibodies. The epitope recognized by Leu-3a and similar clones has been shown to be the location for human immunodeficiency virus (HIV) receptor. We have found a unique blood donor whose CD4+ T-helper lymphocytes were lacking Leu-3a epitope. CD4+ T-helper cells lacking Leu-3a epitope might be resistant to HIV infection.