Representative examples of relative luminescence units (y-axis) after CEM.NKr-CCR5-Luc cells were exposed to virus using different protocols (A), varying multiplicity of infection (MOI) (B), and sampled at different days post infection (PI) (C). Each bar represents the mean and standard error mean from three replicates for NL4–3 (black bar), REJO (blue bar), swarm with maternal envelopes 1431 (red bar), and uninfected cells (white bar).