IL4 and neoplasm: Serum cytokines measured 1 h after the third injection also reflected the prolonged reactivity of iNKT cells to tumor-targeted recombinant CD1d proteins (Fig. 6c), as shown by significant serum levels of IFNγ and IL-4 in mice treated with αGC/sCD1d-anti-CEA protein, while barely any cytokines could be measured after three injections of αGC/sCD1d-anti-HER2 protein.