CD4 and neoplasm: By immune-histochemical assay, there was no existence of CD8+ and CD4+ T cells in the tumor micro-environment in the PBS and mAb (20 μg) groups, but there was existence in the BsAb (20 μg) group (Figure 6f), which suggested that T cells, particularly for CD8+ and CD4+ T cells, could survive for a long time when activated by m3s193 BsAb.