Difference of virus populations in HIV carriers in relation to AZT treatment

To analyse the appearance of AZT-resistant HIV in HIV carriers after AZT treatment and compare the mutations responsible for resistance employing cloned HIV DNA derived from provirus and free virions in plasma, serial blood specimens were taken before and after AZT treatment. RNA in virions in plasma, proviral DNA and RNA from virus isolates by coculture of PBMCs of HIV carriers and healthy blood donors were cloned and sequenced. DNA clones were compared for their nucleotide sequences responsible for AZT resistance. AZT resistance was acquired as early as 2 months after the start of the treatment and follow-up study was performed for 16 months of the treatment. Population of DNA clones was different according to the origin of the DNA or RNA, which indicated that the provirus population in PBMC was different from that in virions in plasma. These data demonstrated the possibility of selective activation of provirus or activation of provirus in organs other than peripheral blood, although the number of cases was small.