title: Contribution of nonneutralizing vaccine-elicited antibody activities to improved protective efficacy in rhesus macaques immunized with Tat/Env compared with multigenic vaccines.
abstract: Previously, chronic-phase protection against SHIV(89.6P) challenge was significantly greater in macaques primed with replicating adenovirus type 5 host range mutant (Ad5hr) recombinants encoding HIVtat and env and boosted with Tat and Env protein compared with macaques primed with multigenic adenovirus recombinants (HIVtat, HIVenv, SIVgag, SIVnef) and boosted with Tat, Env, and Nef proteins. The greater protection was correlated with Tat- and Env-binding Abs. Because the macaques lacked SHIV(89.6P)-neutralizing activity prechallenge, we investigated whether Ab-dependent cellular cytotoxicity (ADCC) and Ab-dependent cell-mediated viral inhibition (ADCVI) might exert a protective effect. We clearly show that Tat can serve as an ADCC target, although the Tat-specific activity elicited did not correlate with better protection. However, Env-specific ADCC activity was consistently higher in the Tat/Env group, with sustained cell killing postchallenge exhibited at higher levels (p < 0.00001) for a longer duration (p = 0.0002) compared with the multigenic group. ADCVI was similarly higher in the Tat/Env group and significantly correlated with reduced acute-phase viremia at wk 2 and 4 postchallenge (p = 0.046 and 0.011, respectively). Viral-specific IgG and IgA Abs in mucosal secretions were elicited but did not influence the outcome of the i.v. SHIV(89.6P) challenge. The higher ADCC and ADCVI activities seen in the Tat/Env group provide a plausible mechanism responsible for the greater chronic-phase protection. Because Tat is known to enhance cell-mediated immunity to coadministered Ags, further studies should explore its impact on Ab induction so that it may be optimally incorporated into HIV vaccine regimens.
authors.affiliation: Vaccine Branch and.
authors.forename: Ruth H
authors.initials: RH
authors.lastname: Florese
authors.forename: Thorsten
authors.initials: T
authors.lastname: Demberg
authors.forename: Peng
authors.initials: P
authors.lastname: Xiao
authors.forename: LaRene
authors.initials: L
authors.lastname: Kuller
authors.forename: Kay
authors.initials: K
authors.lastname: Larsen
authors.forename: L Ebonita
authors.initials: LE
authors.lastname: Summers
authors.forename: David
authors.initials: D
authors.lastname: Venzon
authors.forename: Aurelio
authors.initials: A
authors.lastname: Cafaro
authors.forename: Barbara
authors.initials: B
authors.lastname: Ensoli
authors.forename: Marjorie
authors.initials: M
authors.lastname: Robert-Guroff
mesh_terms: D000256:Adenoviridae / Q000235:genetics / Q000276:immunology; D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis* / Q000502:physiology; D000920:Antibody-Dependent Cell Cytotoxicity / Q000235:genetics / Q000276:immunology; D000998:Antiviral Agents / Q000008:administration & dosage / Q000276:immunology; D001666:Binding Sites, Antibody / Q000235:genetics; D002461:Cell Line, Transformed; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D008253:Macaca mulatta; D008297:Male; D009500:Neutralization Tests; D018449:SAIDS Vaccines / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology*; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014616:Vaccinia virus / Q000235:genetics / Q000276:immunology; D054299:env Gene Products, Human Immunodeficiency Virus / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology*; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000008:administration & dosage* / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D000998:Antiviral Agents; D018449:SAIDS Vaccines; D019444:Vaccines, DNA; D054299:env Gene Products, Human Immunodeficiency Virus; D054322:tat Gene Products, Human Immunodeficiency Virus