title: Restriction of sensitivity of HIV-1-antigen ELISA by serum anti-core antibodies.
abstract: Addition of varying concentrations of HIV-1-seropositive plasma to purified virus particles and soluble viral antigen preparation inhibited the detection of HIV-1-antigen by ELISA. The degree of inhibition on p24 antigen ELISA depended on the relative concentrations of viral antigen and anti-p24 antibodies in the mixtures. The relevance of these observations to clinical specimens was demonstrated when serial plasma samples from nine AIDS-related complex (ARC) patients in a clinical trial of foscarnet therapy were assayed for p24 antigen. Six (66.6%) out of nine patients were negative on screening. However, when their plasma was centrifuged through a sucrose solution, virus particles were pelleted that were depleted of anti-p24 and virus-specific p24 antigen was detected in resuspended pellets obtained from samples from all six patients. Eight serial samples collected from a male homosexual over 50 weeks following seroconversion were also subjected to the separation procedure. HIV-1-antigen was detected in all eight samples. In the light of these observations, the application of the separation technique in monitoring the efficacy of zidovudine or other anti-retroviral therapy should reveal more precise antigen levels in patients who otherwise appear to be antigen-negative in HIV-antigen assays. We propose that the natural history of HIV infections follows a pattern of chronic viral infection with continuous shedding of virus particles circulating as immune complexes.
mesh_terms: D000386:AIDS-Related Complex / Q000209:etiology / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D000956:Antigens, Viral / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D006678:HIV / Q000276:immunology*; D015483:HIV Antibodies; D015488:HIV Antigens; D006801:Humans; D012191:Retroviridae Proteins / Q000276:immunology; D013997:Time Factors; D014758:Viral Core Proteins / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D015483:HIV Antibodies; D015488:HIV Antigens; D012191:Retroviridae Proteins; D014758:Viral Core Proteins