The immune privilege of the eye: human retinal pigment epithelial cells selectively modulate T-cell activation in vitro.
OBJECTIVE
To examine the effect of human retinal pigment epithelial (RPE) cells on phytohemagglutinin (PHA) activation of T cells.


METHODS
Resting peripheral blood lymphocytes (PBLs) were stimulated with PHA with or without the presence of gamma-irradiated RPE cells. Proliferation and the cell cycle profile were thereafter investigated by 3H-thymidine incorporation and flow cytometric analysis. In addition, the PBLs expression of CD69, major histocompatibility complex (MHC) class I and II, CD3, as well as the IL-2 receptor chains were evaluated by flow cytometry, and the content of IL-2 in cell culture supernatant was measured by ELISA.


RESULTS
Human RPE cells were found to suppress PHA-induced proliferation, cyclin A, IL-2R-alpha and -gamma, and CD71 expression and decrease the production of IL-2; but RPE cells do not inhibit the PHA-induced expression of early activation markers CD69, MHC class I and II, and of cyclin D of the PBLs.


CONCLUSIONS
These results are the first to indicate that RPE cells impede generation of activated T cells by interfering with the induction of high-affinity IL-2R-alphabetagamma, IL-2 production, and the expression of CD71 and cyclin A.
Kaestel
Charlotte G
CG
Department of Medical Anatomy, The Panum Institute, University of Copenhagen, Copenhagen, Denmark.
Lovato
Paola
P
Ødum
Niels
N
Nissen
Mogens H
MH
Röpke
Carsten
C
D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D017252:CD3 Complex / Q000378:metabolism; D002453:Cell Cycle; D002460:Cell Line; D049109:Cell Proliferation; D018920:Coculture Techniques; D004261:DNA Replication; D004797:Enzyme-Linked Immunosorbent Assay; D005123:Eye / Q000276:immunology*; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000378:metabolism; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D006801:Humans; D007107:Immune System / Q000502:physiology; D053645:Interleukin-2 Receptor alpha Subunit; D037181:Lectins, C-Type; D008213:Lymphocyte Activation; D010857:Pigment Epithelium of Eye / Q000276:immunology*; D018123:Receptors, Interleukin / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D053645:Interleukin-2 Receptor alpha Subunit; D037181:Lectins, C-Type; D018123:Receptors, Interleukin; D000099192:CD69 Antigens; C508017:IL2RA protein, human