Submitted March 8, 2006
Accepted August 26, 2006
Rapid Quantification of Naive Alloreactive T Cells by TNF-
Production and Correlation with Allograft Rejection in Mice
Michael Brehm*, Julie Mangada, Thomas G. Markees, Todd Pearson, Keith A. Daniels, Thomas B. Thornley, Raymond M. Welsh, Aldo A. Rossini, and Dale L. Greiner
Dept. of Pathology, University of Massachusetts Medical School, Worcester, MA, USA
Dept of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
* Corresponding author; email: michael.brehm{at}umassmed.edu.
Allograft transplantation requires chronic immunosuppression, but there is no effective strategy to evaluate the long-term maintenance of immunosuppression other than assessment of graft function. The ability to monitor naive alloreactive T cells would provide an alternative guide for drug therapy at early, pre-clinical stages of graft rejection and for evaluating tolerance-inducing protocols. To detect and quantify naive alloreactive T cells directly ex vivo, we utilized the unique ability of naive T cells to rapidly produce TNF-
but not IFN-
. Naive alloreactive T cells were identified by the production of TNF- after a 5 hr in vitro stimulation with alloantigen and were distinguished from effector/memory alloreactive T cells by the inability to produce IFN-. Moreover naive alloreactive T cells were not detected in mice tolerized against specific alloantigens. The frequency of TNF--producing cells was predictive for rejection in an in vivo cytotoxicity assay and correlated with skin allograft rejection. Naive alloreactive T cells were also detected in humans, suggesting clinical relevance. We conclude that rapid production of TNF- can be used to quantify naive alloreactive T cells, that it is abrogated after the induction of tolerance and that it is a potential tool to predict allograft rejection.
