Our results with B3 and F6 pro-B cell leukemia cells are entirely consistent with these prior reports that direct presentation by B cell lymphoma cells is immunogenic.51,52 The expression of covalently linked pMHC complexes in B3 and F6 precludes indirect presentation of the source antigen gp70, which is not present in this system. Here, EMB is linked to B-cell non-Hodgkin lymphoma.