A simple one-step method for the preparation of HIV-1 envelope glycoprotein immunogens based on a CD4 mimic peptide.

To counteract the problems associated with the purification of HIV envelope, we developed a new purification method exploiting the high affinity of a peptide mimicking CD4 towards the viral glycoprotein. This miniCD4 was used as a ligand in affinity chromatography and allowed the separation in one step of HIV envelope monomer from cell supernatant and the capture of pre-purified trimer. This simple and robust method of purification yielded to active and intact HIV envelopes as proved by the binding of CCR5 HIV co-receptor, CD4 and a panel of well-characterized monoclonal antibodies. The immunogenicity of miniCD4-purified HIV envelope was further assessed in rats. The analysis of the humoral response indicated that elicited antibodies were able to recognize a broad range of HIV envelopes. Finally, this method based on a chemically synthesized peptide may represent a convenient and versatile tool for protein purification compatible far scale-up in both academic and pharmaceutical researches.