HLA-DPA1 and colorectal neoplasm: To address whether CD4 T cell rejection of HT-29 is alloantigen-specific and better define the potential alloantigen response, we exploited the use of (1) CA46 cells, a B-cell lymphoma cell line expressing fully mismatched HLA-II to HT-29 and (2) HCT116 cells, another colorectal tumor cell line expressing mostly mismatched HLA-II except for DPA1.