Abstract
Purpose: :
Human amnion mesenchyme cells (hAMCs) have the phenotype for neural progenitors and display the ability to differentiate into neuronal cells in vitro. We have reported that acute rejection induced by cellular immunity occurs after subretinal transplant of hAMCs. We analyzed humoral immunity under xenogeneic transplantation of hAMCs, and evaluated long–term survival and differentiation for transplantation to the subretinal space of immunodeficient recipients.
Methods: :
Placenta was obtained at elective cesarean section from volunteers. After staining with PKH26, cultured hAMCs were transplanted trans–sclerally to the subretinal space of normal eyes in 6– to 9–week–old BALB/c mice as normal recipients and C.B17 mice as immunodeficient recipients. Sera were collected from normal recipients at various timepoints after transplantation. Total IgM and IgG were quantified using enzyme–linked immunosorbent assay (ELISA), and anti–human IgM and IgG were analyzed using flow cytometry. Sera from mice into which human lymphocytes were injected subcutaneously were used as positive controls. Eyes were harvested and subretinal PKH26–positive cells were analyzed using confocal microscopy until 24 weeks post–transplantation for survival and expression of retinal markers.
Results: :
Total IgG gradually increased after transplantation. Anti–human IgG increased significantly. Subretinal transplanted hAMCs in immunodeficient recipients survived for 24 weeks near the retinal pigment epithelial layer. Calretinin– and GS–positive PKH26–positive cells were identified.
Conclusions: :
Immunologically normal recipients display a risk of chronic rejection after xenogeneic subretinal transplantation of hAMCs. If transplanted to immunodeficient recipients, hAMCs obtain long–term survival in the subretinal space and possess the potential to differentiating into horizontal cells or Muller glial cells.
Keywords: transplantation • retina • regeneration