The same TILs (Figure 1) also contained significant numbers of IFN-γ–producing E6-specific CD4+ T cells (Figure 3), which, in contrast, did not recognize E6-expressing tumor cells, even when they were induced to express ample surface MHC class II of the correct presenting allele (DQA1*01:02/DQB1*05:02) by IFN-γ treatment or CIITA transduction (Figure 4). Here, CIITA is linked to neoplasm.