title: Immune responses in Ugandan women infected with subtypes A and D HIV using the BED capture immunoassay and an antibody avidity assay.
abstract: BACKGROUND
  Analysis of samples from Uganda using serologic HIV incidence assays reveal that individuals with subtype D infection often have weak humoral immune responses to HIV infection. It is unclear whether this reflects a poor initial response to infection or a waning antibody response later in infection.
  
  
  METHODS
  Samples (N = 2614) were obtained from 114 women aged 18-45 years in the Ugandan Genital Shedding and Disease Progression Study cohort (2001-2009; 82 subtype A, 32 subtype D; median 23 samples/women, range 3-41 samples, median follow-up of 6.6 years). Samples were analyzed using the BED capture immunoassay (cutoff, 0.8 OD-n) and the avidity assay (cutoff, 90% Avidity Index). Antibody maturation was assessed by having the BED capture enzyme immunoassay (BED-CEIA) or avidity value exceed the assay cutoff 1 or 2 years after infection. The waning antibody response was measured by having the BED-CEIA or avidity value fall >20% below the maximum value.
  
  
  RESULTS
  For the BED-CEIA, 8 women with subtype A infection and 3 women with subtype D infection never progressed previously the cutoff value (median, 5.9 years follow-up after infection). Six women with subtype D infection never achieved an avidity index >90%. Subtype did not impact the proportion of women whose assay values regressed by >20% of the maximal value (for BED-CEIA: 33% for A, 41% for D, P = 0.51; for avidity: 1% for A, 6% for D, P = 0.19).
  
  
  CONCLUSIONS
  The higher frequency of misclassification of individuals with long-term subtype D infection as recently infected using serologic incidence assays reflects a weak initial antibody response to HIV infection that is sustained over time.
authors.affiliation: *Laboratory of Immunoregulation, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, NIH, Baltimore, MD; †Clinical Sciences, Family Health International 360, Durham, NC; ‡Case Western Reserve University, Cleveland, OH; and §Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Longosz
authors.forename: Charles S
authors.initials: CS
authors.lastname: Morrison
authors.forename: Pai-Lien
authors.initials: PL
authors.lastname: Chen
authors.forename: Eric
authors.initials: E
authors.lastname: Arts
authors.forename: Immaculate
authors.initials: I
authors.lastname: Nankya
authors.forename: Robert A
authors.initials: RA
authors.lastname: Salata
authors.forename: Veronica
authors.initials: V
authors.lastname: Franco
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Quinn
authors.forename: Susan H
authors.initials: SH
authors.lastname: Eshleman
authors.forename: Oliver
authors.initials: O
authors.lastname: Laeyendecker
mesh_terms: D000293:Adolescent; D000328:Adult; D000915:Antibody Affinity; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005838:Genotype; D015483:HIV Antibodies / Q000097:blood*; D015658:HIV Infections / Q000276:immunology*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification; D006801:Humans; D008875:Middle Aged; D014454:Uganda; D055815:Young Adult
chemical_list: D015483:HIV Antibodies