FIG. 2.
Receptor use of paired plasma and CSF isolates. Diagrams showing results after infection of U87.CD4 cells expressing CCR5, CXCR4, or chimeric CXCR4/CCR5 receptors, with paired plasma (gray bars) and CSF (open bars) virus isolates. (A–F) The six paired isolates with discordant use of chimeric receptors. (G) Paired isolates of concordant R5narrow phenotype. (H) Paired isolates of concordant R5broad3 phenotype. Infections are measured as p24 protein content in the cell culture supernatant. # indicates a p24 value <1. The criterium for discordant use is a >10-fold difference in p24 antigen production between the infections.