Increased liver parasite burden in αβ T-cell-deficient mice. Groups of five C57BL/6, TCRδ−/−, TCRβ−/−, class I-deficient (B2M−/−), and class II-deficient (Aβb−/−) mice were challenged with 5.0 × 104 sporozoites, and liver parasite burden was measured by quantitative-competitive RT-PCR of parasite-specific 18S rDNA. Error bars indicate 1 standard deviation of the mean. ∗, significant increase (P < 0.05) in liver parasite burden compared to the liver parasite burden of C57BL/6 mice.