To identify T. gondii genetic loci responsible for the strain-differences in CD8 T cell responses to infections, and ultimately ROCTR, we assessed 29 strains of F1 progeny from a type I x type II cross (F1 IxII), 34 strains of F1 progeny from a type II x type III cross (F1 IIxIII), and 32 strains of F1 progeny from a type I x type III cross (F1 IxIII) in an antigen-specific CD8 T cell activation assay (Figure 1A) (Kongsomboonvech et al., 2020). Here, CD8A is linked to infection.