We prepare our mesenchymal stem cells (MSCs) from horses different than the patient to be treated. This phenomenon is called “allogeneic stem cell therapy”.
In contrast to pluripotent stem cells, the safe use of allogeneic MSCs has been described in both humans and horses (Carrade et al., 2011a; Carrade et al., 2011b; Fang et al., 2007). Moreover, Guest has reported in 2008 that the injection of allogenic MSCs in equine tendon lesions did not induce any increase in cell mediated immune response in comparison to autologous MSCs (donor and receiver are the same animal). The low immunogenicity of these cells suggests that MSCs can be transplanted universally without matching between donors and recipients. However, donor animals should be stalled in quarantine and repeated blood testing for transmittable diseases is required.
As mentioned previously, the donor MSCs used by GST are negative for the typical rejection proteins, MHC class II and only present low expression levels of MHC class I. Moreover, chondrogenic induction does not alter the MHC levels, reflecting low immunogenicity, which should be permissive for allogenic transplantations.
Several studies have even reported the successful use of allogeneic human MSCs to treat patients suffering from therapy-resistant graft versus host disease (Fang et al., 2007; Ringden et al., 2006). By using allogeneic MSCs, we have the opportunity to select high quality MSCs and perform a bacteriological examination at the moment the stem cell samples are frozen. These samples leave the lab as soon as the bacteriological examination confirms their sterility.
Transplantation possibilities for peripheral blood MSCs
Definition of allogeneic, autologous & xenogeneic transplantations