Performance of HIV-1/2 viral stocks in real-time RT-qPCR and HIV-1 p24 antigen tests.

Individual viral stocks identified as HIV-2 were obtained from the NIAID AIDS Reagent and Reference Repository and SeraCare, Inc. The HIV-1 subtype and HIV-2 group identification is based upon data sheets provided by NIAID and from publications. An HIV-1 Subtype B isolate from the United States (91US_4) was used as an HIV-1 control. Viral RNA was extracted and tested in HIV-2 real-time RT-qPCR assays. Viral isolates selected for testing in the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 v2.0 quantitative RNA assay and the Perkin-Elmer p24 Antigen test included the two viral isolates that were not amplified in the HIV-2 real-time RT-qPCR assays, three HIV-2 viral isolates that amplified well and the HIV-1 91US_4 isolate. Although the HIV-2 RT-qPCR assays were not optimized, the HIV-2 amplifications were robust for the majority of the isolates tested as reflected in the HIV-2 RNA concentrations reported based upon relative values extrapolated from the NIH-Z standard for each primers/probe set. The CDC 310340 and CDC 310342 viral stocks were not amplified in HIV-2 RT-qPCR assays but were quantified and reactive in HIV-1 specific tests. PD = Primer Design LTD HIV-2 PCR Kit primers/probe. SM = Delarue et al [12] primers/probe set. TND = Target Not Detected. UNK is unknown group. Viral isolate was not tested (−).