EVALUATION OF A NEW 3RD GENERATION ANTI-HIV-1- ANTI-HIV-2 ASSAY WITH INCREASED SENSITIVITY FOR HIV-1 GROUP O/

Although the HIV-1 group O virus found in two persons of Cameroonian o rigin has been described in 1990 (De Leys et al., 1990), sera from gro up O infected individuals became available only recently. Several stud ies showed that some of the anti-HIV-1/HIV-2 screening tests failed to detect all of these samples (Loussert-Ajaka et al., 1994; Simon et al ., 1994; Schable et al., 1994; Gurtler et al., 1995). In the current v ersion of an anti-HIV-1/anti-HIV-2 screening assay, namely the Vironos tika HIV Uni-Form II, an HIV-O specific peptide was introduced in orde r to improve HIV-1 group O reactivity. The peptide was derived from th e immunodominant region of HIV-1 group O gp41 strain ANT70. All 30 ant i-HIV-l group O sera were detected by the so-called plus O assay, whil e 29 samples of this panel were positive the current assay. The sensit ivity of the plus O assay for anti-HIV-l and anti-HIV-2 positive sampl es is identical to that of the reference test without HIV-1 group O pe ptide. The clinical specificity of the HIV Uni-Form II plus O assay is improved to greater than or equal to 99.92% by an adjustment of the c oat concentration of HIV-1 p24 (to avoid false positive p24 only react ions) without affecting sensitivity of the assay. The specific reactio n of an HIV-I group O specific rabbit serum for quality control purpos es is presented.