To explore whether Rop7 CD8 T cells were equally capable of participating in an immune response, we transferred 1 × 105 sorted CD8+ tetramer+ T cells from Rop7-I, -II or -III mice into congenic BALB/c CD45.1 mice and monitored their expansion upon infection with Toxoplasma gondii. The gene discussed is CD8A; the disease is infection.