CCR5-reactive antibodies in seronegative partners of HIV-seropositive individuals down-modulate surface CCR5 in vivo and neutralize the infectivity of R5 strains of HIV-1 In vitro
| Autor: | Francesco Mazzotta, Adriano Lazzarin, Mario Clerici, Claudia Barassi, Renato Longhi, Claudia Pastori, Samuele E. Burastero, Antonio G. Siccardi, Lucia Lopalco, Giuseppe Tambussi |
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| Rok vydání: | 2000 |
| Předmět: |
Male
Receptors CCR5 viruses Immunology Down-Regulation HIV Antibodies Peripheral blood mononuclear cell Binding Competitive Neutralization Tests Risk Factors HIV Seronegativity HIV Seropositivity Immunology and Allergy Humans Immunoadsorption Chemokine CCL4 Immunosorbent Techniques Infectivity biology Virulence Immune Sera Autoantibody virus diseases Macrophage Inflammatory Proteins Virology In vitro Chemotaxis Leukocyte Epitope mapping CCR5 Receptor Antagonists Cell Migration Inhibition biology.protein HIV-1 Leukocytes Mononuclear Female Binding Sites Antibody Antibody Epitope Mapping Conformational epitope Protein Binding |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 0022-1767 |
| Popis: | Exposure to HIV does not necessarily results in infection. Because primary HIV infection is associated with CCR5-tropic HIV variants (R5), CCR5-specific Abs in the sera of HIV-seronegative, HIV-exposed individuals (ESN) might be associated with protection against infection. We analyzed sera from ESN, their HIV-infected sexual partners (HIV+), and healthy controls (USN) searching for CCR5-specific Abs, studying whether incubation of PBMC with sera could prevent macrophage inflammatory protein 1β (Mip1β) (natural ligand of CCR5) binding to CCR5. Results showed that Mip1β binding to CCR5 was not modified by sera of either 40 HIV+ or 45 USN but was greatly reduced by sera of 6/48 ESN. Binding inhibition was due to Abs reactive with CCR5. The CCR5-specific Abs neutralized the infectivity of primary HIV isolates obtained from the corresponding HIV+ partners and of R5-primary HIV strains, but not that of CXCR4-tropic or amphitropic HIV strains. Immunoadsorption on CCR5-transfected, but not on CXCR4-transfected, cells removed CCR5-specific and virus-neutralizing Abs. Epitope mapping on purified CCR5-specific Abs showed that these Abs recognize a conformational epitope in the first cysteine loop of CCR5 (aa 89–102). Affinity-purified anti-CCR5-peptide neutralized the infectivity of R5 strains of HIV-1. Anti-CCR5 Abs inhibited Mip1β-induced chemotaxis of PBMC from healthy donors. PBMC from two ESN (with anti-CCR5 Abs) were CCR5-negative and could not be stimulated by Mip1β in chemotaxis assays. These results contribute to clarifying the phenomenon of immunologic resistance to HIV and may have implications for the development of a protective vaccine. |
| Databáze: | OpenAIRE |
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