FIG. 4.

(A) FIV viral DNA detection after incubation with antibodies recognizing the CCR3, CXCR4, or CCR5 chemokine receptors. Uninfected PBMC and PBMC infected with either viral strain but without pretreatment with antibody served as negative and positive controls, respectively. (B) FIV DNA levels were measured relative to the amount of template DNA, as determined by amplification of the HLA-DQα gene. (C) The greatest decrease in the viral DNA levels compared to positive control cultures was observed after treatment with antibodies to the CCR3 chemokine receptor for both strains (59.8 ± 2.4% for Petaluma, 77.1 ± 1.1% for V₁CSF). Antibodies to the CCR5 receptor significantly inhibited infection with V₁CSF, decreasing detectable FIV DNA levels by 71.2 ± 0.7% of the control value, but not with Petaluma. For both viruses, infection was decreased in the presence of antibodies recognizing the CXCR4 receptor (29.3 ± 5.7% for Petaluma, 63.3 ± 1.6% for V₁CSF). Viral DNA levels were not affected by preincubation with nonspecific ARPA or BSA. ∗∗, P < 0.01; ∗, P < 0.05.