Infectivities of HIV-1 primary isolates and laboratory-adapted strains were compared in primary fetal enterocytes and the colonic epithelial cell line HT29. Infection by two laboratory strains, HIV-1 NDK and HIV-1 NDKA4, which were adapted on CEM and HT29 cells, respectively, produced significant amounts of virus in both target cell systems.
Intestinal cells were resistant to infection with HIV-1 primary isolates regardless of their genetic subtype or SI/NSI phenotype, Biological properties of analyzed viruses rather than differences in cultivation system seem to be responsible for differences between these in vitro and ex vivo results.