CD4 and neoplasm: To compare the ability of tumour-specific B cells and host myeloid APCs to present tumour antigen to CD4+ T cells, we developed a general experimental approach of adoptively co-transferring CFSE labeled 5C.C7 T cells with either I-E positive or I-E negative (termed I-E+ and I-E−, respectively) SWHEL B cells, into I-E+ or I-E− tumour bearing hosts (Figure 1a).