In vitro methods for generating highly purified EBV associated tumor antigen-specific T cells by using solid phase T cell selection system for immunotherapy

Adoptive cell transfer immunotherapy has been utilized to treat EBV related human malignancies including post-transplant lymphoproliferative diseases, Hodgkin's lymphoma and nasopharyngeal carcinoma. However, there are limited options available for tumor antigen-specific T cell purification. Here we describe a novel solid phase T cell selection system, in which monocytes or EBV transformed B-lymphocytes are immobilized on solid support for antigen-specific T cell purification. We hypothesize and prove that antigen-specific T cells recognize their cognate antigens and bind to them faster than non-antigen specific T cells. Therefore antigen-specific T cells can be concentrated on the surface after removing the non-adherent cells by washing. The optimal selection time for both EBV-specific T cells and LMP2-specific T cells is studied. Our data demonstrate that the frequency of antigen-specific T cells can be increased by > 20-fold after selection. Moreover, activated antigen-specific T cells proliferate more rapidly than non-specific T cells, further increasing the frequency and purity of antigen-specific T cells. This new T cell selection system is superior to traditional repeated stimulation methods in generating tumor antigen-specific T cells. We are able to generate large quantities of highly purified T cells of subdominant antigens LMP2 within 2 weeks after T cell activation for adoptive cell transfer immunotherapy with this simple, rapid and inexpensive T cell selection system.