NF-kappaB signaling, elastase localization, and phagocytosis differ in HIV-1 permissive and nonpermissive U937 clones.

To identify positive or negative factors for HIV-1 infectivity, clones from the U937 promonocytic cell line that express similar levels of CD4 and CXCR4, but differ in HIV-1 susceptibility, were compared. In contrast to HIV-1 permissive clone 10 (plus), nonpermissive clone 17 (minus) was adherent to coverslips coated with chemokines, was phagocytic, killed bacteria, and expressed human leukocyte elastase (HLE) in a granule-like compartment (HLEG) that was never detected at the cell surface (HLECS). In contrast to the minus clone, the plus clone expressed HLE on the cell surface and was adherent to coverslips coated with the HLECS ligands alpha1proteinase inhibitor (alpha1PI, alpha1antitrypsin) and the HIV-1 fusion peptide.