In vivo alloreactive potential of ex vivo-expanded primary T lymphocytes.
BACKGROUND
We are presently investigating the therapeutic potential of herpes simplex-thymidine kinase-expressing donor T cells in the setting of a T cell-depleted allogeneic bone marrow transplantation. The generation, expansion, and selection of the gene-modified T cells require a 12-day ex vivo culture period in high-dose interleukin (IL)-2 that could significantly alter their in vivo alloreactivity.


METHODS
We evaluated the alloreactive potential of such cultured cells in a murine allogeneic bone marrow transplantation model.


RESULTS
The present studies demonstrate that ex vivo-expanded cultured T cells are capable of strong alloreactivity as evidenced by the occurrence of lethal acute graft-versus-host disease (GVHD). However, GVHD mortality after administration of the cultured T cells occurred later than after the administration of a same number of fresh T cells. Similar kinetics of GVHD-induced mortality between cultured and fresh T cells required a 10-fold increase in the number of cultured T cells, indicating a reduced alloreactive potential of these cells. The addition of a 2-day "resting" period in low-dose IL-2 resulted in T cells with enhanced alloreactive potential identical to the alloreactivity observed with fresh T cells.


CONCLUSIONS
Ex vivo IL-2-expanded T cells are capable of significant in vivo alloreactivity. However, an increase in the number of cultured T cells administered or the introduction of a short resting culture period prior to infusion is necessary in order to achieve in vivo alloreactivity identical to the alloreactivity observed with fresh T cells.
Contassot
E
E
Laboratoire de Thérapeutique Immuno-moléculaire, Etablissement de Transfusion Sanguine de Franche-Comté, Besançon, France.
Murphy
W
W
Angonin
R
R
Pavy
J J
JJ
Bittencourt
M C
MC
Robinet
E
E
Reynolds
C W
CW
Cahn
J Y
JY
Hervé
P
P
Tiberghien
P
P
D000208:Acute Disease; D000818:Animals; D016026:Bone Marrow Transplantation; D017690:Cell Transplantation; D018014:Gene Transfer Techniques; D006086:Graft vs Host Disease / Q000401:mortality / Q000601:surgery / Q000628:therapy; D006561:Herpes Simplex / Q000201:enzymology*; D007376:Interleukin-2 / Q000494:pharmacology; D008212:Lymphocyte Depletion; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013601:T-Lymphocytes / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology*; D013937:Thymidine Kinase / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014019:Tissue Donors; D014184:Transplantation, Homologous
D007376:Interleukin-2; D013937:Thymidine Kinase