Study on the Zidovudine Resistance of HIV-1 Isolated Strains in Korea

ABSTRACT

To examine AZT resistance of HIV-1 isolates from AZT treated or untreated Korean, several biological characteristics such as syncytium formation, HIV-1 reverse transcriptase activity and the p24 antigen production in MT-2 cells infected with 4 HRT_1 isolates were determined. As controls, we tested HIV-1 HTLV-IIIB and pre-drug isolate as AZT susceptible strains, in addition to HIV-1 RTMC/MT-2 and post-drug isolate as AZT resistant strains. When the inoculum size of HIV-1 was 300 TCID50well and 100 TCID50/well, the AZT susceptibility of AZT untreated HIV-1 isolates 8806 and 9571 were similar to that of HIV-1 HTLV-IIIB and AZT-susceptible HIV-1 strains. When we evaluated AZT resistance of isolates HRs-1 8812 and 9113 treated with AZT for 36 months by observation of syncytium formation, HIV-1 8812 showed resistance simillar to that of HIV-1 RTMC/MT-2 strain forming syncytium up to AZT 1microgram/ml, and HIV-1 9113 showed resistance identical with that of AZT-resistant HIV-1 strain which formed syncytium up to AZT 10 microgram/ml. Especially, when we evaluated AZT resistance by HIV-1 reverse transcriptase activty and the p24 antigen production, HIV-1 isolates 8812 and 9113 showed much higher resistance (>10 - 200 fold) compared with HN-1 RTMC/MT-2 and AZT-resistant HIV-1 strain.