FIG. 2.

The depletion of CD4⁺ T cells inhibits immune protection in β₂M^−/− mice. P. yoelii (Py) sporozoite-immunized (spz imm) β₂M^−/− mice, with or without depleted T cells, were challenged. Protection was determined by measuring (A) parasitemia in daily blood smears or (B) levels of liver-stage parasites by RT-PCR. Pooled results from two independent experiments are shown (n, 8 to 9 mice total). Following treatment with anti-CD4 MAb GK 1.5, FACS analysis confirmed the depletion of CD4⁺ T cells, with 0.22% CD4⁺ T cells in treated versus 26% in untreated β₂M^−/− mice and 0.09% versus 21.7% in treated versus untreated WT mice, respectively. CD8⁺-T-cell levels in β₂M^−/− mice were 0.41%, versus 19.8% in WT mice. Anti-AsialoGM, anti-asialoglyprotein 1 antiserum.