In contrast, CCR5-deficiency in mice diminished susceptibilityto infection with Plasmodium berghei (ANKAstrain) by reducing CD8+ T cell accumulation and T-helper1 cytokine production in the brain [9].If, in some cases, CCR5 represents a susceptibility factor for the spread ofpathogens in the brain, in others it confers resistance against the development ofsevere disease. This evidence concerns the gene CD8A and infection.