CD4 and neoplasm: Several features of γδ T cells makes them potential suitable candidates for anti-tumor immunotherapy: (i) their ability to recognize tumor antigens independently of MHC restriction and co-stimulation (166); (ii) production of effector cytokines (TNF-α and IFN-γ) and conferring cytotoxicity against tumor cells both directly and indirectly by stimulating macrophages and DCs (167–169); and (iii) activated γδ T cells acquire the phenotype of antigen presenting cells (APCs) and induce CD4+ and CD8+ T cell proliferation and cytotoxicity (170).