FIG. 4.
FIV infection of human GHOST cells. Human GHOST cells were infected with 104.5 TCID50 of parent or chimeric FIV strains/ml, and infection was assessed after 24 h by nested PCR amplification of the FIV pol gene from genomic DNA. GHOST cell lines used included nontransfected parent cells (P), cells transfected with the human CCR3 (3), CXCR4 (4), or CCR5 (5) receptor, and cells transfected with all three chemokine receptors (A). Mock-infected cells (U) served as negative controls, and amplification of a water blank (W) was performed to ensure the absence of contamination. The role of specific chemokine receptors in FIV infection was determined by infecting cells in the absence (none) or presence of antibodies to CCR3 (αR3), CCR5 (αR5), or CXCR4 (αX4), alone or in combination. Although Petaluma infected all cell lines, infection by either V1CSF or FIV-Ch was restricted to cells expressing CCR3 or CCR5. For all viruses, anti-CXCR4 antibodies inhibited infection, but antibodies to CCR3 or CCR5 affected infection by V1CSF and FIV-Ch.