Purification of melanoma reactive T cell by using a monocyte-based solid phase T-cell selection system for adoptive therapy.

The generation of melanoma-reactive T cells with the characteristics necessary for in vivo effectiveness remains a considerable obstacle to the application of adoptive cell therapy. Recent clinical success with adoptive cell therapy for melanoma is motivating additional investigation to improve the technology of generating such tumor reactive lymphocytes. Here we describe a novel solid phase T-cell selection system, in which monocytes are immobilized on solid support for antigen-specific T-cell purification. We hypothesized and proved that antigen-specific T cells recognize their cognate antigens and bind to them faster than nonantigen-specific T cells and are concentrated on the surface after removing the nonadherent cells by washing. Moreover, activated antigen-specific T cells proliferated more rapidly than nonspecific T cells, further increasing the frequency and purity of antigen-specific T cells. Optimal selection times for Melan-A-specific T cells are studied. Our data demonstrated that T-cell selection can usually increase the frequency of tumor antigen-specific T cells by >10-fold, whereas T-cell expansion after the selection boost the frequency of tumor antigen-specific T cells by another approximately 10-fold. More importantly, these T cells are generated under more physiologic conditions. This new T-cell selection system is superior to traditional repeated stimulation methods in generating tumor antigen-specific T cells for adoptive cell immunotherapy. This inexpensive and simple T-cell selection system can produce large quantity of highly purified Melan-A-specific T cells within 2 weeks after T-cell activation.