CD4 and neoplasm: To visualize antigen-specific interactions between TRP-1 CD4+ T cells and MHC-II+ CD11c+ antigen-presenting cells, we further generated amelanotic (Tyr-KO) HCmel12 Trp1-KO cells expressing tagBFP, injected them into opposite legs of CD11c-Venus transgenic mice that harbour fluorescent antigen-presenting immune cells31 and treated established tumours with adoptively transferred eGFP+ TRP-1 CD4+ T cells (Fig. 2g and Extended Data Fig. 5a,b).