title: Multiple HIV-1-specific IgG3 responses decline during acute HIV-1:  implications for detection of incident HIV infection.
abstract: OBJECTIVE
  Different HIV-1 antigen specificities appear in sequence after HIV-1 transmission and the immunoglobulin G (IgG) subclass responses to HIV antigens are distinct from each other. The initial predominant IgG subclass response to HIV-1 infection consists of IgG1 and IgG3 antibodies with a noted decline in some IgG3 antibodies during acute HIV-1 infection. Thus, we postulate that multiple antigen-specific IgG3 responses may serve as surrogates for the relative time since HIV-1 acquisition.
  
  
  METHODS
  We determined the magnitude, peak, and half-life of HIV-1 antigen-specific IgG1 and IgG3 antibodies in 41 HIV-1-infected individuals followed longitudinally from acute infection during the first appearance of HIV-1-specific antibodies through approximately 6 months after infection.
  
  
  METHODS
  We used quantitative HIV-1-binding antibody multiplex assays and exponential decay models to estimate concentrations of IgG1 and IgG3 antibodies to eight different HIV-1 proteins including gp140 Env, gp120 Env, gp41 Env, p66 reverse transcriptase, p31 Integrase, Tat, Nef, and p55 Gag proteins during acute/recent HIV-1 infection.
  
  
  RESULTS
  Among HIV-1-specific IgG3 responses, anti-gp41 IgG3 antibodies were the first to appear. We found that anti-gp41 Env IgG3 and anti-p66 reverse transcriptase IgG3 antibodies, in addition to anti-Gag IgG3 antibodies, each consistently and measurably declined after acute infection, in contrast to the persistent antigen-specific IgG1 responses.
  
  
  CONCLUSIONS
  The detailed measurements of the decline in multiple HIV-specific IgG3 responses simultaneous with persistent IgG1 responses during acute and recent HIV-1 infection could serve as markers for detection of incident HIV infection.
authors.affiliation: Duke University Human Vaccine Institute, Duke University, Durham, North Carolina, USA.
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Yates
authors.forename: Judith T
authors.initials: JT
authors.lastname: Lucas
authors.forename: Tracy L
authors.initials: TL
authors.lastname: Nolen
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Vandergrift
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Soderberg
authors.forename: Kelly E
authors.initials: KE
authors.lastname: Seaton
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Denny
authors.forename: Barton F
authors.initials: BF
authors.lastname: Haynes
authors.forename: Myron S
authors.initials: MS
authors.lastname: Cohen
authors.forename: Georgia D
authors.initials: GD
authors.lastname: Tomaras
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D000918:Antibody Specificity / Q000276:immunology*; D000937:Antigen-Antibody Reactions; D015415:Biomarkers / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015488:HIV Antigens / Q000276:immunology*; D015658:HIV Infections / Q000175:diagnosis* / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D019562:Viral Load; D055815:Young Adult
chemical_list: D015415:Biomarkers; D015488:HIV Antigens; D007074:Immunoglobulin G