A capture enzyme immunoassay for detection of HIV-2/SIV antigen

An antigen capture enzyme immunoassay was developed for the demonstration of human immunodeficiency virus type 2 (HIV-2) and simian immunodeficiency virus (SIV). The assay (HIV-2 CE) has a sensitivity of approximately 250 pg/ml of HIV-2/SIV antigen. The HIV-2 CE was 4-16 times more sensitive than the Abbott HIV-1 antigen assay for detection of HIV-2/SIV antigen in cell culture supernatant. The sensitivity for detection of HIV-2/SIV antigen in serum or plasma was 98.5% in the HIV-2 CE and 95.5% in the Abbott HIV-1 antigen assay. The specificity of the HIV-2 CE was 99.2% (one false positive among 119 negative sera) whereas the Abbott assay was 100% specific. The HIV-2 CE detected antigen in supernatants from cultures of peripheral blood mononuclear cells of macaque monkeys infected with HIV-2 or SIV about 1 week before a reverse transcriptase (RT) microassay was positive and remained positive for at least 1 week after the RT assay had become negative. Three cultures from persistently infected monkeys were positive only in the HIV-2 CE, reflecting a higher sensitivity compared to the RT microassay. Thus, the HIV-2 CE was more sensitive than the Abbott HIV-1 antigen assay for detection of HIV-2/SIV antigen in culture supernatants as well as in serum/plasma. Furthermore, the HIV-2 CE showed a higher sensitivity than the RT microassay for detection of HIV-2/SIV in cell culture supernatants.