Abstract
Human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) are the causative agents of acquired immune deficiency syndrome. Our interests have focused on HIV entry into target cells and HIV cell tropism. The cell tropism of HIV and the determinants of a cell's susceptibility to HIV infection have been mainly explained by the combination of HIV surface proteins, Env, and expression of CD4 and coreceptors on the target cells. The coreceptors are molecules belonging to the G protein-coupled 7-transmembrane receptors, especially chemokine receptors. We propose that many researchers working in this field have noticed that our system of using a human glioma cell line, NP-2, has been quite useful for the identification of HIV coreceptors, for the determination of coreceptor usage in HIV strains and for the isolation of primary HIV-1 strains, and for the titration of infectivity. The properties of the assay systems using NP-2 cells that we have developed are summarized in this review through an introduction of some of our work.
