CD4 and hepatocellular carcinoma: Immmunohistochemistry analysis of the liver tissues of Ad-mPRT-122aT/GCV treated syngeneic and immune-competent C57BL mouse with orthotopic HCC showed that CD3(+), CD4(+), CD8(+), CD11c(+), CD80(+), CD86(+), and MHC-1(+) cells, but not CD56(+) cells, were significantly infiltrated in the tumor microenvironment (Fig. 6A).