Incidence immunoassay for distinguishing recent from established HIV-1 infection in therapy-naive populations.
OBJECTIVE
To identify a specific marker of recent HIV-1 infection.


METHODS
The humoral immune response in individuals recently infected with HIV-1 was followed by analysing the antibody isotype-specific response generated to HIV-1 antigens in sequential samples collected during and following seroconversion.


METHODS
Antibody isotype-specific HIV-1 Western blots were analysed to identify interactions indicative of recent HIV-1 infection. These responses were further quantified using an antibody isotype-specific enzyme-linked immunoabsorbent assay based on recombinant HIV-1 antigens.


RESULTS
During maturation of the immune response to HIV-1 infection, a rapid and enduring IgG1 isotype response was seen to all the major proteins transcribed by env, gag and pol. An early transient peak of IgG3 reactivity to p24 was observed over an interval of approximately 1-4 months following HIV-1 infection. The presence of IgG3 reactivity to p24 permitted established infection to be distinguished from recently infected individuals during this time period.


CONCLUSIONS
An assay for anti-p24 IgG3 reactivity would provide an estimate of the incidence of HIV infection that may be applicable for epidemiological surveys as well as for monitoring new infections during vaccine trials and for managing treatment programmes.
Wilson
Kim M
KM
National Serology Reference Laboratory, St Vincent's Institute, Melbourne, Australia. kim@nrl.gov.au
Johnson
Elizabeth I M
EI
Croom
Hayley A
HA
Richards
Kim M
KM
Doughty
Larissa
L
Cunningham
Philip H
PH
Kemp
Bruce E
BE
Branson
Bernard M
BM
Dax
Elizabeth M
EM
D000208:Acute Disease; D000914:Antibodies, Viral / Q000276:immunology; D000918:Antibody Specificity / Q000276:immunology; D000937:Antigen-Antibody Reactions / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology; D015415:Biomarkers / Q000097:blood; D015153:Blotting, Western / Q000379:methods; D015331:Cohort Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D016655:HIV Core Protein p24 / Q000276:immunology; D015658:HIV Infections / Q000453:epidemiology / Q000276:immunology*; D015497:HIV-1 / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D012680:Sensitivity and Specificity; D016036:Seroepidemiologic Studies
D000914:Antibodies, Viral; D000956:Antigens, Viral; D015415:Biomarkers; D016655:HIV Core Protein p24; D007074:Immunoglobulin G