In vitro activation of cytotoxic T-lymphocytes by hTERT-pulsed dendritic cells.

Multiple myeloma has been considered a weakly immunogenic malignancy that can cause profound defects in the immune system. An important issue for the immunotherapy of myeloma is the identification of appropriate tumor-associated antigens (TAAs). Recently, hTERT (human telomerase reverse transcriptase) was detected on a majority of human malignancies. In the studies reported here, we studied antigen-specific and HLA-A2-restricted cytotoxic activity against an ARH77 myeloma cell line in vitro. An HLA-A2-specific hTERT-derived nonapeptide ((540)ILAKFLHWL(548)) was used as a TAA. Myeloma-specific cytotoxic activity of hTERT-reactive cytotoxic lymphocytes (CTLs) was established by repeated stimulation of the CTLs via dendritic cells loaded with hTERT-derived nonapeptide. These studies were able to demonstrate that hTERT-reactive T-lymphocytes can be identified and expanded using relatively simple in vitro techniques consisting of antigen-specific stimulation, immunomagnetic sorting, and then induction of rapid expansion.