CD4 and infection: We chose to include animals from these previous studies to bolster the total sample size and introduce the following perturbations to the measured responses: 1) maternal plasma viral load was higher in CD4-depleted animals and lower in CD4-depleted animals receiving a potently-RhCMV neutralizing and dose-optimized IgG infusion, 2) humoral responses were generally delayed in CD4-depleted dams, and 3) dams receiving passive IgG infusion before infection had high levels of RhCMV-specific IgG in the first week (Figure 5).