INCREASING GENOTYPIC AND PHENOTYPIC SELECTION FROM THE ORIGINAL GENOMIC RNA POPULATIONS OF HIV-1 STRAINS LAI AND MN (NM) BY PERIPHERAL-BLOOD MONONUCLEAR CELL-CULTURE, B-CELL-LINE PROPAGATION AND T-CELL-LINE ADAPTATION

Objective: To address the question of whether T-cell-line adaptation of the original LAI and MN (NM) HIV-1 populations biased the interpretation of the intraindividual and population-wide virus distributions. Patients and methods: HIV-1 genomic RNA coding for the gp120 C2V3 region was obtained from serum samples of patients LAI and MN and compared to the proviral DNA derived from simultaneously sampled peripheral blood mononuclear cells (PBMC) as well as B- and T-cell lines. Results: Two (10%) of 20 clones of HIV-1 LAI RNA and none of 16 clones of the HIV-1 MN RNA carried syncytium-inducing (SI)-determining amino-acid changes. HIV-1 LAI RNA formed one SI and two non-SI (NSI) phylogenetic clusters. The HIV-I LAI DNA in PBMC included both SI and NSI clones but lacked one NSI cluster and contributed NSI clones to the SI cluster as well as an SI clone to the NSI cluster, indicating the existence of an intermediate SI/NSI genotype. In vitro culture using either primary cells or B-cell lines yielded only SI clones, distributed over two SI/NSI mixed clusters. Long-term propagation in T-cell lines further restricted the clonality and yielded SI clones belonging to only one cluster. On the population level, HIV-1 LAI, MN and BRU sequences all clustered according to the individual host and apart from each other and separate from the epidemiological controls without notable influence of SI/NSI distinction or cell-culture adaptation. Conclusion: Our data demonstrate a selection bias during the cell-line adaptation of HIV-1 strains LAI and MN with more impact on phenotypic than on genotypic characteristics.