ABSTRACT
A human CD4-positive T cell line from a donor homozygous negative for the chemokine receptor CCR5 was established, characterized, and used for determining the coreceptor usage of human immunodeficiency virus type 1 (HIV-1) isolates. Clones of this IL-2 dependent human T-cell lymphotropic virus type 1 (HTLV-I) immortalized cell line, named IsnoR5 clones 1 and 2, are susceptible to infection by HIV-1 isolates that use CXCR4 as a coreceptor but resistant to infection by CCR5 tropic HIV-1 viruses. HIV-1 isolates whose replication is inhibited in IsnoR5 cells in the presence of the bicyclam AMD 3100, a CXCR4 specific inhibitor, utilize a coreceptor distinct from CCR5 and CXCR4. Using a panel of primary HIV-1 isolates we have shown that a single T cell line is sufficient to discriminate between use of CCR5, CXCR4 or an alternative coreceptor. As IsnoR5 clone 1 cells revealed the existence of even minor populations of CXCR4-using virus variants, they could be useful for the early identification of changes in coreceptor usage in HIV infected individuals facilitating the timely introduction of appropriate clinical treatments.
