Detection of early anti-p24 HIV responses in EIA- and immunoblot-negative individuals. Implications for confirmatory testing.
A sensitive and specific radioimmunoprecipitation assay was developed for the detection and analysis of anti-HIV antibody response in human sera with the use of 125I-labelled purified HIV proteins with subsequent sodium-dodecylsulfate gel electrophoresis (125I-RIPA). The 125I-RIPA was shown to be as specific but at least 1 log more sensitive with respect to the detection of gp41env and p24gag than the immunoblot analysis as tested in serum samples from several risk groups. Sequential sera were obtained from 9 individuals who seroconverted for HIV antibodies. In 4 individuals, antibody to p24gag was detected in earlier serum samples by the 125I-RIPA than by EIA or immunoblot; in the other 5 individuals, the detection of p24gag concorded in enzyme-linked immunosorbent assay (EIA), immunoblot and 125I-RIPA. Moreover, in one of 78 randomly chosen EIA-negative sera from individuals at high risk, antibodies to p24gag could be detected by the 125I-RIPA. This early seroconversion was confirmed 3 months later by means of immunoblotting and EIA. The specificity of the 125I-RIPA was further demonstrated by analyzing sequential EIA-negative serum samples from 10 individuals at risk for AIDS, collected during 2 years at 3-monthly intervals. All 80 serum samples were found to be negative in the 125I-RIPA and the individuals revealed no signs of HIV infection. The 125I-RIPA technique may be a valuable confirmatory assay in the serology of HIV infections. The sensitivity of this test provides a reliable measure of effective sensitivity when new-generation screening tests are evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)
Huisman
J G
JG
Central Laboratory, Netherlands Red Cross Blood Transfusion Service.
Winkel
I N
IN
Lelie
P N
PN
Tersmette
M
M
Goudsmit
J
J
Miedema
F
F
D000163:Acquired Immunodeficiency Syndrome / Q000175:diagnosis; D000914:Antibodies, Viral / Q000032:analysis*; D011232:Chemical Precipitation; D004797:Enzyme-Linked Immunosorbent Assay; D005189:False Positive Reactions; D006678:HIV / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007158:Immunologic Techniques; D007457:Iodine Radioisotopes; D008297:Male; D011863:Radioimmunoassay / Q000379:methods*; D013997:Time Factors; D014764:Viral Proteins / Q000032:analysis
D000914:Antibodies, Viral; D007457:Iodine Radioisotopes; D014764:Viral Proteins