Using adoptive transfer of MSP1-specific TCR Transgenic CD4 T cells to study the effect of chronic P. chabaudi infection on protection, we showed that the memory population (CD4+CD44hiCD25-) of previously activated T cells from chronically infected mice protected better than T cells from mice that were treated with chloroquine, an anti-malarial drug previously shown to clear P. chabaudi (AS), one month after infection [7]. Here, CD4 is linked to infection.