The lack of susceptibility to HIV-1 infection in human hematopoietic progenitor TF-1 cell line correlates with the absence of LFA-1 (CD11a) surface adhesion molecule.

Although substantially unsusceptible to HIV-1 infection, human hematopoietic progenitors (CD34+ cells) express significant amounts of gp120-binding CD4 molecules. As some experimental evidence suggests the need for one or more putative cellular accessory factor(s) for efficient CD4-mediate HIV-1 infection, we analyzed the presence and distribution of various adhesion molecules on the surface of two HIV-1-susceptible cell lines (H9 and A3.01) and one HIV-1-unsusceptible, CD4-positive, human hematopoietic progenitor cell line (TF-1). The only difference observed concerned the LFA-1 CD11a protein that has already been shown to be necessary for cell fusion in HIV-1-infected T4 lymphocytes. CD11a was present in a high percentage of HIV-1-susceptible cells and absent in HIV-1-unsusceptible TF-1 cells. A significant increase in HIV-1 replication was obtained in CD11a-enriched H9 cells in comparison with an almost completely CD11a-deprived H9 cell population. The lack of susceptibility to HIV-1 infection in human CD34+ cells may depend on various factors. Nevertheless, the lack of CD11a in a CD34+, CD4+ human hematopoietic progenitor cell line suggests that this molecule may be implicated in the susceptibility to HIV-1 infection.