Generation of BKV-Specific T Cells for Adoptive Therapy Against BKV Nephropathy

Nephropathy associated with BK virus has emerged as an important cause of allograft failure in renal transplant recipients. Here we exploited a recently developed novel monocyte based solid phase T cell selection system, in which monocytes are immobilized on solid support, for antigen-specific T cell purification. The underlying hypothesis of this new method is that antigen-specific T cells recognize, bind their cognate antigens faster than non-specific T cells and are concentrated on the surface after removing the non-adherent cells by washing. 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. Optimal selection times for BK virus-specific T cells are studied. Our data demonstrated that T cell selection can usually increase the frequency of antigen-specific T cells by 10 fold, whereas T cell expansion following the selection boost the frequency of antigen-specific T cells by another ~10 fold. This new T cell selection system is superior to traditional stimulation method (i.e. simply mixing antigen presenting cells and lymphocytes together) in generating antigen-specific T cells. This inexpensive and simple T cell selection system can produce large quantity of highly purified BK virus-specific T cells within 1–2 weeks after initial T cell activation.