ABSTRACT
Natural antibodies to gp41 inhibit HIV-1 replication through the recognition of two different regions, corresponding to the leucine zipper motif in the HR1 alpha-helix and to another motif within HR2 region, hosting 2F5 and 4E10 epitope. This study aimed at reproducing such protective responses through VLP vaccination. Six regions covering the alpha-helical regions of gp41 were conjugated to the surface of AP205 phage-based VLPs. Once administered in mice via systemic or mucosal route, these immunogens elicited high titers of gp41-specific IgG. Immunogenicity and HIV infectivity reduction were obtained either with HR2 regions or with peptides where aminoacid strings were added to either the C-terminus or N-terminus of core epitope in HR1 region. Antibody-dependent cell cytotoxicity (ADCC) activity was induced by one of the HR2 epitopes only. These results may have relevant implications for the development of new vaccinal approaches against HIV infection.
Subject(s)
AIDS Vaccines/administration & dosage , AIDS Vaccines/immunology , HIV Antibodies/blood , HIV Envelope Protein gp41/immunology , HIV-1/immunology , Animals , Bacteriophages/genetics , Cytotoxicity Tests, Immunologic , Drug Carriers/administration & dosage , Female , Genetic Vectors , Immunoglobulin G/blood , Mice , Mice, Inbred BALB C , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunology , Vaccines, Virosome/administration & dosage , Vaccines, Virosome/immunologyABSTRACT
AIDS is mainly a sexually transmitted disease, and accordingly, mucosal tissues are the primary sites of natural human immunodeficiency virus type-1 (HIV-1) transmission. Mucosal immunoglobulin A (IgA) antibody specific for HIV-1 envelope gp41 subunit is one correlate of protection in individuals who are highly sexually exposed to HIV-1 but remain persistently IgG seronegative (HEPS). Understanding these peculiar IgAs at the gene and functional level is possible only with monoclonal IgAs. We have constructed a mucosal Fab IgA library from HEPS and have characterized a series of HIV-1 IgAs specific for gp41 that, in vitro, are transcytosis-blocking and infection-neutralizing. Characterization of their IgA genes shows that Fab specific for the gp41 membrane-proximal region harbors a long heavy-chain CDR3 loop (CDRH3) similar to the two broadly neutralizing IgG monoclonal antibodies, 2F5 and 4E10. Furthermore, the selected Fab IgA shows extensive somatic mutations that cluster in the CDR regions, indicating that affinity maturation due to an antigen-driven process had occurred in HEPS individuals, presumably upon multiple exposures to HIV. This analysis of HEPS monoclonal IgA gives a unique opportunity to correlate an antibody function (resistance to a pathogen in vivo) with an antibody gene. Such neutralizing monoclonal IgAs could be used in microbicide formulation.
Subject(s)
Antibodies, Monoclonal/immunology , CD4-Positive T-Lymphocytes/virology , Cervix Uteri/immunology , HIV Antibodies/immunology , HIV Envelope Protein gp41/immunology , HIV Infections/prevention & control , HIV Seronegativity/immunology , HIV-1/immunology , Immunoglobulin A, Secretory/immunology , Mucous Membrane/immunology , Peptide Fragments/immunology , Vagina/immunology , Virus Internalization , Adult , Amino Acid Sequence , Antibodies, Monoclonal/genetics , Antibodies, Monoclonal/isolation & purification , CD4-Positive T-Lymphocytes/immunology , Conserved Sequence , Environmental Exposure , Female , Gene Rearrangement, B-Lymphocyte , HIV Antibodies/genetics , HIV Antibodies/isolation & purification , HIV Infections/immunology , HIV-1/physiology , Humans , Immunity, Innate/immunology , Immunoglobulin A, Secretory/genetics , Immunoglobulin A, Secretory/isolation & purification , Immunoglobulin Fab Fragments/genetics , Immunoglobulin Fab Fragments/immunology , Molecular Sequence Data , Peptide Library , Sequence Alignment , Sequence Homology , Sexual PartnersABSTRACT
Poliovirus (PV) can persist in vivo in the intestine of immunocompromised hosts for years. Moreover, immunocompetent individuals who have survived paralytic poliomyelitis sometimes develop the post-poliomyelitis syndrome (PPS), consisting of a variety of symptoms including new muscular atrophies. PPS may be due to PV persistence. We have developed models of PV persistence in neural cells and epidermoid cells. Cell determinants are of crucial importance for the establishment of persistent infections in human neuronal cells, whereas viral determinants play the primary role in human epidermoid HEp-2 cells. The results obtained with these in vitro models show the capacity of PV to persist and reveal a virus and cell co-evolution involving PV-receptor interactions. In addition, they suggest that several mechanisms are used by PV to establish and maintain persistent infections.
