Here we examine directly the B-cell uptake and presentation of the self-antigen myelin basic protein (MBP), a self-antigen considered to be involved in the pathogenesis of MS [27], exploiting the recognition of the immunodominant peptide MBP85-99 presented on HLA-DR15 by mAb MK16 [28]. Here, MBP is linked to myeloid sarcoma.