Presence of myeloma antigen–specific type 1 T cells in BM of myeloma patients. (A) Isolated BM T cells from MM patients were tested by short-term IFN-g Elispot assay for reactivity against autologous DCs pulsed with either MUC11-100 long peptide, tetanus toxoid (TT) as positive control, or hu IgG as negative control. (B) Ex vivo isolated BM T cells from HLA0201-positive MM patients were tested for reactivity against autologous DCs pulsed with HLA-A0201–restricted epitope MUC1 12-20 or HIVgag77-85 (negative control antigen). (C) Isolated, purified CD81 BM T cells from MM patients were tested by short-term IFN-g Elispot assay for reactivity against autologous DCs pulsed with lysate derived from myeloma cell line RPMI-8226 (MM), or lysates derived from the myeloma-unrelated tumor breast cancer cell line MCF7 (MaCa) or from the promonocytic leukemia cell line U937 (Leu), which served as negative control antigens. Representative experiments of 4 different MM patients are shown in (A-C). Respective cumulative data are shown in (D-F). N: number of patients. *Significant difference compared with respective control group (P < .05, 2-sided Student t test). TA, tumor antigen.