Ex vivo expanded, transduced CTLs increase in the peripheral blood prior to engraftment in allogeneic recipients.

Shown are the median GFP⁺ (or NGFR⁺) cells/mL and total white blood cell count (WBC) ± SD for each group of dogs studied following 9.2 Gy TBI. Transduced cells were measured by flow cytometry of hemolyzed peripheral blood. (A) Engraftment following transplantation of allogeneic marrow and GFP⁺ (or NGFR⁺) CTLs (n = 6). There was a sharp increase in the number of transduced CTLs in the peripheral blood on days +5 to +7 after transplantation, followed by a decline in transduced CTLs on neutrophil recovery. (B) Rejection of allogeneic marrow and GFP⁺ CTLs. In dogs E716 and E815, GFP⁺ cells did not increase substantially after transplantation and subsequently were undetectable at days +11 and +9 after transplantation, respectively. Both dogs sustained an initial recovery of granulocytes to 1800 and 800/μL on days +10 and +8, respectively, followed by loss of granulocytes and GFP⁺ cells and emergence of donor-reactive lymphocytes. (C) Autologous marrow and GFP⁺CTL (n = 2). In both recipients, GFP⁺ cells were detected in the peripheral blood, but without a steep rise in GFP⁺cells prior to neutrophil recovery.