Assessment of antibody assays for identifying and distinguishing recent from long-term HIV type 1 infection.
We evaluated 16 antibody assays for their performance in discriminating recent from established HIV-1 infection. These approaches were based on antigen specificity, quantity, conformation dependence, and avidity/affinity of HIV-specific antibodies. A panel of 41 sera from subjects who had seroconverted in the previous 2-6 months (n = 20) and from subjects with established infection (>1 year, n = 21) were run in each assay. Compared with anti-Gag and anti-Pol responses, quantitative anti-Env antibody levels were initially lower and ultimately higher, resulting in the greatest spread and least overlap between incident and established infection. Quantitative measurement included end-point titer in Western blot, end-point titer or response at a given dilution in solid-phase enzyme immunoassays (EIAs) with recombinant proteins or synthetic peptides, and IgG capture assays that reflect the relative proportion of IgG that is anti-HIV antibody. Focusing on the anti-env response, we measured specific responses to the V3 region of gp120, to the CD4-binding site of gp120, to a peptide corresponding to the immunodominant region of gp41, and to conformation-dependent epitopes of gp120. We also measured antibody affinity for gp41 peptide and the relative avidity for gp120 or gp41 peptide by thermal or urea-elution assays. These assays also discriminated recent from established infection but were not necessarily superior to the quantitative anti-Env assays. Appropriate approaches, based on distinct principles or combination of principles, can be used to develop simple assays for identifying individuals recently infected with HIV-1.
Parekh
B S
BS
HIV Immunology and Diagnostics Branch, Division of AIDS, STD, and TB Laboratory Research, National Center for Infectious Disease, Centers for Disease Control and Prevention, U.S. Public Health Service, Atlanta, Georgia 30333, USA. BSP1@CDC.GOV
Pau
C P
CP
Kennedy
M S
MS
Dobbs
T L
TL
McDougal
J S
JS
D000915:Antibody Affinity; D015704:CD4 Antigens / Q000276:immunology; D003937:Diagnosis, Differential; D000939:Epitopes / Q000276:immunology; D015683:Gene Products, gag / Q000276:immunology; D015684:Gene Products, pol / Q000276:immunology; D015483:HIV Antibodies / Q000097:blood / Q000276:immunology*; D015488:HIV Antigens / Q000276:immunology; D015699:HIV Envelope Protein gp120 / Q000276:immunology; D015700:HIV Envelope Protein gp41 / Q000276:immunology; D015658:HIV Infections / Q000097:blood / Q000175:diagnosis*; D006679:HIV Seropositivity / Q000097:blood / Q000175:diagnosis*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D016056:Immunodominant Epitopes / Q000276:immunology; D007124:Immunoenzyme Techniques; D010452:Peptide Biosynthesis; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000276:immunology
D015704:CD4 Antigens; D000939:Epitopes; D015683:Gene Products, gag; D015684:Gene Products, pol; D015483:HIV Antibodies; D015488:HIV Antigens; D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; D016056:Immunodominant Epitopes; D011994:Recombinant Proteins