HIV-1 is the causative agent of AIDS. CD-4 is the cellular receptor for HIV-1 and its amino acid sequence is known. A small peptide of CD4 was identified as responsible, at least in part, for the binding of the HIV-1 envelope protein to cells. Studies are underway to develop agents capable of recognizing this part of CD-4 in the hope that anti HIV-1 drugs may be delivered to this part of the CD4 molecule. In addition, a 14-member synthetic peptide corresponding to a portion of the primary neutralizing epitope from the HIV-1 gp120 was found to align very closely with this CD4 region. Binding studies are currently underway to test at the interaction of polymers of this peptide and antibody to the polymer with CD-4-bearing cells.