CD4 and infection: As the role of early immune events in limiting T. gondii infection and shaping adaptive immunity is well documented, Ag+ CD4 and CD8 T cells were evaluated at day 5 and 8 p.i. Given that uninfected mice could not be excluded by measuring the Ab response or the parasite burden so early after infection, mice from either group that were consistently diverging from the average and/or were not different from naive mice were excluded from the analysis.