V3 LOOP CORE REGION SEROTYPING OF HIV-1-INFECTED PATIENTS USING THE FHV EPITOPE PRESENTING SYSTEM

We have reported recently a new epitope presenting system based on the Flock House Virus (FHV) capsid protein. The HIV-1 V3 loop core sequen ce IGPGRAF was inserted in different sites of this carrier molecule. I mmunoreactivity experiments and molecular modelling consistently showe d that the most reactive recombinant protein displayed the IGPGRAF seq uence in a conformation which is most similar to that of a V3 loop ref erence structure. The same insertion site was then used to display the V3 loop apex sequences of six different HIV-1 isolates. Sera from 32 HIV-1 infected patients were examined for their reactivity to our chim eric proteins and the results were compared with those obtained using synthetic V3 loop peptides. The data obtained were confirmed by nested PCR amplification and direct sequencing of the patient's V3 loops. Th e results showed that the V3 loop serotyping using the FHV hybrid prot eins, was more specific than that obtained using synthetic peptides. T his system will therefore be a useful tool for the correct evaluation of the immune response against different V3 loop core sequences. Copyr ight (C) 1997 Elsevier Science B.V.