In vitro generated autoimmune regulatory T cells enhance intravitreous allogeneic retinal graft survival.
OBJECTIVE
The authors demonstrated that in vitro-generated alpha-melanocyte stimulated hormone (MSH)-induced Treg cells specific to ocular autoantigen suppress ocular autoimmune disease in vivo when adoptively transferred. They examined the possibility of using these ocular autoantigen-specific Treg cells to promote the survival of a retinal allograft placed in the mouse vitreous.


METHODS
Enhanced green fluorescent protein (eGFP)-C57BL/6 neonatal retinal microaggregates were injected into the vitreous of B10-RIII mice before the adoptive transfer of interphotoreceptor retinoid-binding protein (IRBP; an ocular antigen) or ovalbumin (OVA)-specific alpha-MSH-induced Treg cells. GFP transplants were imaged in vivo on days 7 and 12. In addition, on day 12, the eyes were cryosectioned and immunostained with a panel of neuronal and immune cell markers.


RESULTS
GFP allografts underwent no detectable changes in size on days 7 and 12 in the B10-RIII mice injected with IRBP-specific Treg cells; however, mice that received OVA-specific Treg cells or no Treg cells experienced remarkable reductions in graft size on day 12. Only one quarter of the original size was seen. Using neuronal-specific markers, immunohistochemistry showed that the architecture of the retinal allografts in the IRBP Treg cell-injected group had intact rosettes and neuronal cells on the outermost layer, whereas the allografts in the OVA Treg cell-injected mice were disorganized. Immune cell-specific markers demonstrated that Treg cells and activated microglial cells were found in the retinal allografts of the mice injected with IRBP Treg cells, but not in the retinal allografts of the OVA Treg-injected mice.


CONCLUSIONS
These results demonstrate that adoptive transfer of alpha-MSH-generated IRBP-specific Treg cells promotes retinal allograft survival and development.
Ng
Tat Fong
TF
Schepens Eye Research Institute, Boston, MA 02114, USA.
Kitaichi
Nobuyoshi
N
Taylor
Andrew W
AW
D019264:Adoptive Transfer; D000818:Animals; D000831:Animals, Newborn; D001324:Autoantigens / Q000276:immunology*; D015551:Autoimmunity; D005136:Eye Proteins / Q000276:immunology; D019084:Fluorescent Antibody Technique, Indirect; D006085:Graft Survival / Q000502:physiology*; D049452:Green Fluorescent Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000473:pathology; D010047:Ovalbumin / Q000276:immunology; D012160:Retina / Q000637:transplantation*; D012177:Retinol-Binding Proteins / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014184:Transplantation, Homologous; D014822:Vitreous Body / Q000601:surgery*; D000521:alpha-MSH / Q000276:immunology; D000099214:Retinol-Binding Proteins, Interstitial
D001324:Autoantigens; D005136:Eye Proteins; D049452:Green Fluorescent Proteins; D010047:Ovalbumin; D012177:Retinol-Binding Proteins; D000521:alpha-MSH; D000099214:Retinol-Binding Proteins, Interstitial; C485184:enhanced green fluorescent protein