When used alone, 4/7 ICR cells could respond to IL-4 and promote T cell proliferation but could not induce antitumor activity, but combing 4/7 ICR and CAR resulted in antigen and cytokine dependent antitumor T cell responses in vitro and in xenograft tumor models in humanized mice.44 Wang et al developed a similar receptor called 4/21 ICR which used the IL-4Rα ectodomain (AA1-233) and the transmembrane and intracellular domain of IL-21R(AA233-538), which was expressed via the lentiviral vector pRRLSIN. Here, IL4 is linked to neoplasm.