Abstract: Peptidyl sequences, called mimotopes, are disclosed which mimic the binding site of the broadly neutralizing human monoclonal antibody, 2G12, specific for the HIV protein gp120. The mimotopes are identified from a chimeric protein III (pIII) phage display library, each phage containing an additional random 15 amino acids near the N-terminus of pIII. Immunological conjugates of HIV-specific mimotopes that are useful for vaccination against HIV infection are disclosed. Methods for using the mimotopes and their immunological conjugates as part of an HIV vaccine regime, as well as diagnostic tools to perform viral assays, are also disclosed.