CD8A and hepatocellular carcinoma: To further dissect the contribution of CD8+ T cells to IRG1-promoted HCC tumorigenesis, Rag−/− mice, which lack mature T cells and B cells, were cross mated with Irg1−/− mice to obtain Irg1+/+Rag−/− (RWT) and Irg1−/−Rag−/− (RKO) mice.