This finding, along with the capacity of CIITA-expressing tumor cells to process and present antigenic peptides to CD4+ T cells in vitro (21, 22), supports the hypothesis that much of the tumor-specific TH cell triggering takes place in the tumor tissue as consequence of the recognition of MHC-II–TAA peptide complexes expressed by CIITA-transfected tumor cells. Here, CD4 is linked to neoplasm.