The invention relates to an enhanced method for rapid immunogen selection (RIS) based on the binding a library of recombinant viruses containing randomized variants of a surface polypeptide displayed to said neutralizing antibodies. HIV gp120 has been used as immuonogen. The invention relates as well to the use of the HIV gp120 immunogens isolated according to the RIS method of the invention in medicine for the treatment of diseases caused by a virus and in diagnosis for the identification of neutralizing antibodies in a patient.
