title: Human T helper cells specific for HIV reverse transcriptase: possible role in intrastructural help for HIV envelope-specific antibodies.
abstract: Cooperation between B cells specific for an antigen exposed on a viral structure and T helper (Th) cells specific for an internal antigen, as demonstrated with influenza, hepatitis B and rabies viruses, has been termed intrastructural help. Th cells specific for internal proteins of HIV, which are much less mutated than its exposed antigens, may be valuable in vaccine design against this virus. We investigated the human Th repertoire specific for the core HIV antigen reverse transcriptase (p66), and determined whether these cells could be candidate intrastructural T helpers. CD4+ T lines and clones were generated from non-immune individuals by stimulation with p66-pulsed antigen-presenting cells (APC). Specific lines were obtained with p66 from 19 out of 21 (90%) of these individuals, vs. 7 out of 29 (24%) with gp120. Diverse epitopes were recognized by different individuals, and various V beta genes were used by these clones. Clones using the same V beta genes were of diverse origin, according to VDJ region sequence. Of these lines 45% responded to p66 in the context of HIV virions. Moreover, p66-specific clones could respond to APC that had internalized HIV complexed with envelope-specific monoclonal antibodies, suggesting that p66-specific Th cells may participate in intrastructural help. These studies indicate that p66-specific Th cells are detectable in vitro in most naive individuals and exhibit clonal heterogeneity, and that the majority recognize an HIV conserved antigen. They respond to p66 following processing of whole virions and are clearly candidates for intrastructural help. If confirmed in vivo, p66 should be included among vaccine candidates investigated to optimize the anti-HIV Th response.
authors.affiliation: Department of Immunology, San Martino Hospital, University of Genoa, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Manca
authors.forename: D
authors.initials: D
authors.lastname: Fenoglio
authors.forename: M T
authors.initials: MT
authors.lastname: Valle
authors.forename: G
authors.initials: G
authors.lastname: Li Pira
authors.forename: A
authors.initials: A
authors.lastname: Kunkl
authors.forename: R S
authors.initials: RS
authors.lastname: Balderas
authors.forename: R G
authors.initials: RG
authors.lastname: Baccala
authors.forename: D H
authors.initials: DH
authors.lastname: Kono
authors.forename: A
authors.initials: A
authors.lastname: Ferraris
authors.forename: D
authors.initials: D
authors.lastname: Saverino
mesh_terms: D000595:Amino Acid Sequence; D000938:Antigen-Presenting Cells; D000954:Antigens, Surface / Q000276:immunology*; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D002999:Clone Cells; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; D015483:HIV Antibodies / Q000276:immunology*; D015488:HIV Antigens / Q000276:immunology*; D054303:HIV Reverse Transcriptase; D006801:Humans; D008211:Lymphocyte Cooperation; D008969:Molecular Sequence Data; D012194:RNA-Directed DNA Polymerase / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics; D014771:Virion / Q000276:immunology / Q000648:ultrastructure
chemical_list: D000954:Antigens, Surface; D015483:HIV Antibodies; D015488:HIV Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase