Expression of CD26 Does Not Correlate with the Replication of Macrophage-Tropic Strains of HIV-1 in T-Cell Lines

Abstract

Strains of human immunodeficiency virus type 1 (HIV-1) differ significantly in both genetic content and biological properties. One of the earliest discovered differences between HIV-1 strains was divergence in the relative ability of different strains to replicate in either T-cell lines or monocytes/macrophages. This observation has led to the suggestion that molecules present on the surface of HIV-susceptible cells other than CD4 may interact with gp120 in facilitating the entry of HIV-1 into host cell populations. Several reports have suggested that CD26, a cell surface protease expressed on many cells of the immune system including some CD4+T-cells and macrophage, may be an accessory molecule for HIV-1 entry. Recently, it has also been reported that the expression of high levels of CD26 correlates with the entry and replication of macrophage-tropic strains of HIV-1 in a T-cell line. In this report, we demonstrate that replication of macrophage-tropic strains of HIV-1 in T-cell lines is independent of CD26 expression. From this observation, we conclude that CD26 plays no role in the entry of HIV-1 into these cells.