Approaches to avoid immune responses induced by repeated subcutaneous injections of allogeneic umbilical cord tissue-derived cells.

Background: Cellular treatments for repairing diseased tissues represent a promising clinical strategy. Umbilical cord tissue-derived cells (UTC) are a unique source of cells with a low immunogenic profile and potential for tissue repair. By using UTC from miniature swine, we previously demonstrated that despite their low immunogenic phenotype, UTC could induce an immune response under certain inflammatory conditions and after multiple subcutaneous (SC) injections.

In vivo observations of cell trafficking in allotransplanted vascularized skin flaps and conventional skin grafts.

The problem of allogeneic skin rejection is a major limitation to more widespread application of clinical composite tissue allotransplantation (CTA). Previous research examining skin rejection has mainly studied rejection of conventional skin grafts (CSG) using standard histological techniques. The aim of this study was to objectively assess if there were differences in the immune response to CSG and primarily vascularized skin in composite tissue allotransplants (SCTT) using in vivo techniques in order to gain new insights in to the immune response to skin allotransplants.

Recipient damage after musculocutaneous transplant rejection.

Background: In the event of a composite allograft failure, damage to the recipient tissues may make retransplantation impossible. This study aimed to quantify the damage after composite allograft failure to assess whether retransplantation is feasible.

Methods: Rats (n=6) in the group I received composite musculocutaneous flap allotransplants (WF-->Lew) with immunosuppression allowing healing-in of the allograft before being tapered allowing rejection.

Immunogenicity of umbilical cord tissue derived cells.

Umbilical cord tissue provides a unique source of cells with potential for tissue repair. Umbilical cord tissue-derived cells (UTCs) are MHC class I (MHCI) dull and negative for MHC class II (MHCII), but can be activated to increase MHCI and to express MHCII with IFN-gamma stimulation. Mesenchymal stem cells with similar characteristics have been inferred to be nonimmunogenic; however, in most cases, immunogenicity was not directly assessed.