However, we recently discovered that an adoptive transfer of CD8+ immune T cells isolated from infected wild-type (WT) mice, which are genetically resistant to the infection, was able to markedly reduce numbers of cysts in the brains of infected, immunodeficient mice, such as SCID and nude, when the recipient animals received the T cells after having developed large numbers of cysts in their brains (12, 13). This evidence concerns the gene CD8A and infection.