Mesenchymal Stem Cells Do Not Activate Cytotoxic T Lymphocytes

Stockholm, Sweden -

Mesenchymal stem cells are far advanced in clinical development with trials being conducted for conditions ranging from multiple sclerosis to Crohn's Disease. One attractive aspects of these cells is their relatively low immunogenicity, thus offering the possibility of performing transfer across allogeneic barriers without need for immune suppression.

In a recent paper (Rasmusson et al. Mesenchymal stem cells fail to trigger effector functions of cytotoxic T lymphocytes. J Leukoc Biol. 2007 Jul 3) the ability of mesenchymal stem cells to elicit cytotoxic T cell responses was examined.

The investigators found that mesenchymal stem cells pulsed with high concentrations of antigen recognized by activated T cells would not trigger lysis. This was despite the fact that the mesenchymal stem cells expressed levels of MHC I which would be sufficient to induce lysis in other cell types.

Avoidance of lysis was also observed in the allogeneic CTL context in that as compared to allogeneic lymphoid cell lines, the mesenchymal stem cells did not elicit cytotoxic responses.

These data support ongoing evidence of tolerogenic potential of mesenchymal stem cells.