MM-engrafted mice have BM cells and spleen cells expressing human β2-microglobulin, IgH VDJ and clonotypic transcripts.

Each lane represents femoral bone marrow or vertebral tumor from an individual mouse. The numerical designation indicates the patient from whom the injected cells were obtained. (A) Bone marrow (femur) from mice engrafted with cells from patient 1. RNA from the indicated tissues was amplified in RT-PCR using the indicated primers. Histone primers detect both human and mouse transcripts. Primers for human β2 microglobulin detect only human transcripts. n = uninjected NOD SCID: C = water control. (B) Clonotypic transcripts in RNA of engrafted mice. A second set of tissues from individual mice, were tested for histone, β2 microglobulin and clonotypic transcripts in nested RT-PCR using first primers to FR2/Jh in the first stage and patient 1-specific primers for CDR2/CDR3 in the second stage. Each lane represents femoral BM, or a vertebral tumor from an individual mouse injected with cells from patient 1. (C) Patient-specific primers are specific. Patient-specific primers for patients 2 and 9 were tested in a crisscross specificity experiment. Each lane represents femoral BM cells from an individual mouse injected with either cells from patient 2 or 9. RNA from each mouse was amplified in nested RT-PCR using FR2/Jh primers, followed by CDR2/CDR3 primers specific for either patient 2 or 9. Because the PCR products are patient-specific, the size of the product varies with each individual patient.