Selection of HIV-1 genotypes by cultivation in different primary cells.

Objectives: To determine the representation of particular HIV-1 genotypes during cultivation in different primary cell-culture systems compared with the spectrum of the quasispecies in vivo.

Methods: Primary isolates of HIV-1 were recovered by isolation in cultures of lymphocytes, mixed mononuclear cells (MNC), and monocytes/macrophages. Nucleotide sequence determination of the C2-V3 region of gp120 of HIV was performed on 10-20 independently isolated clones derived by polymerase chain reaction from the culture systems, the uncultured peripheral blood MNC (PBMC) as well as plasma.

Results: Several predominant HIV genotypes were found in the uncultured PBMC from each of the patients. The most frequent genotypes in PBMC were also the most frequent types in plasma. In addition, lymphocytes, macrophages or mixed MNC cultures allowed the outgrowth of variants that were underrepresented in uncultured PBMC. We showed that the virus cultivation systems used in this study selected differently for the genetic variants. Whereas some genotypes were present in all three culture systems, although at different frequencies, others were exclusively found in a specific culture system.

Conclusions: These results demonstrate that monocyte/macrophage and mixed MNC culture systems complement the standard lymphocyte culture in terms of the spectrum of genotypically different virus variants obtained in vitro.