TFRC and infection: At 16 days post-infection only 30–40% of B cells were positive for the activation markers (CD23 Δ2A 4-day p-value <0.001, Δ2A 8-day and 16-day p-value <0.0001) (CD23 Δ2A/Δ2B 4-day p-value <0.01, Δ2A/Δ2B 8-day and 16-day p-value <0.0001) (CD71 Δ2A 4, 8, 16-day p-value <0.0001) (CD71 Δ2A/Δ2B 4-day p-value <0.001, Δ2A/Δ2B 8-day and 16-day p-value <0.0001) (Figure 4B and 4C).