Successful generation of sperm protein 17 (Sp17)-specific cytotoxic T lymphocytes from normal donors: Implication for tumor-specific adoptive immunotherapy following allogeneic stem cell transplantation for Sp17-positive multiple myeloma

Some protein 17 (Sp17) is a highly immunogenic cancer-testis antigen expressed by tumour cells from up to 30% of patients with multiple myeloma (MM). We recently successfully generated Sp17-specific human leucocyte antigen (HLA)-A1 and B27-restricted cytotoxic T lymphocytes (CTLs) from the peripheral blood of a healthy donor. Because CTLs were able to kill HLA-matched fresh myeloma cells, it may be possible to generate and administer myeloma-specific donor T cells to MM patients following allogeneic stem cell transplantation to enhance graft-versus-myeloma (GVM) without inducing graft-versus-host disease (GVHD). To determine how widely applicable this approach is, we have determined the ability to generate Sp17-specific CTLs from four consecutive healthy donors with other HLA class I phenotypes. We found that Sp17-specific HLA class I-restricted CTLs could be easily generated from all four donors. Sp17-specific CTLs were primarily CD8 in phenotype and produced interferon-gamma and very little interleukin-4. These T cells killed target cells primarily via the perforin-mediated route. These results therefore suggest that myeloma-specific donor T-cell infusion that targets Sp17 to selectively enhance GVM could be applicable to patients with SP17(+) MM.