title: Induction of high levels of antibodies recognizing the neutralizing epitope ELDKWA and the D- or K-position-mutated epitopes by candidate epitope vaccines against HIV-1.
abstract: Monoclonal antibody 2F5 recognizing the ELDKWA epitope on HIV-1 gp41 has a significant neutralization potency against 90% of the investigated viruses of African, Asian, American, and European strains, but the antibody responses to the epitope 2F5 in HIV-1-infected individuals were very low. We attempted to induce high levels of epitope-specific antibodies to ELDKWA and its three mutated epitopes by candidate epitope vaccines. The four candidate epitope vaccines all induced strong antibody responses at dilutions from about 1:6,400 to 1:25,600. We tested the cross-reactions between these antisera and four epitope peptides. The ELDKWA-specific antisera showed strong cross-reactivity with three neutralizing-resistant mutated epitopes which contain changes in the D or K positions of the epitope sequence. Virus variants containing these changes could escape neutralization by monoclonal antibody 2F5. In immunoblotting analysis, the ELDKWA, ELDEWA, and ELEKWA epitope specific antibodies all recognized rsgp41 which confirms that the antibodies against both mutated epitopes, ELDEWA and ELEKWA, could cross-react with the native epitope on rsgp41. Although it is not clear whether the polyclonal antibodies induced by the ELDKWA epitope vaccine could neutralize the mutated viruses containing these mutated epitopes, it is conceivable that epitope vaccines based on mutated epitopes could induce strong antibody responses with predefined epitope specificity to neutralize mutated viruse containing the mutated epitope. An epitope vaccine, using different epitopes including mutated epitopes, could provide a new concept for developing a new vaccine against HIV-1.
authors.affiliation: Laboratory of Immunology, Research Centre for Medical Science, and School of Life Science and Engineering, Tsinghua University, Beijing, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Xiao
authors.forename: X
authors.initials: X
authors.lastname: Dong
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
mesh_terms: D016915:AIDS Vaccines / Q000276:immunology*; D000818:Animals; D000939:Epitopes / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D015483:HIV Antibodies / Q000096:biosynthesis* / Q000097:blood / Q000276:immunology; D015700:HIV Envelope Protein gp41 / Q000737:chemistry / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D009154:Mutation; D009500:Neutralization Tests; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D011817:Rabbits; D014611:Vaccination
chemical_list: D016915:AIDS Vaccines; D000939:Epitopes; D015483:HIV Antibodies; D015700:HIV Envelope Protein gp41; D010455:Peptides