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Iris pigment epithelium expressing CD86 (B7-2) directly suppresses T cell activation in vitro via binding to cytotoxic T lymphocyte-associated antigen 4.

Sugita S, Streilein JW - J. Exp. Med. (2003)

Bottom Line: When IPE were blocked with anti-CD86 or were derived from CD80/CD86 (but not CD80) knockout (KO) mice, the cells displayed reduced capacity to suppress T cell activation.IPE also failed to suppress activation of T cells in the presence of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) immunoglobulin or if the T cells were obtained from CTLA-4 (but not CD28) KO mice.Thus, ocular immune privilege is achieved in part by subversion of molecules that are usually used for conventional immune costimulation.

View Article: PubMed Central - PubMed

Affiliation: Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.

ABSTRACT
A monolayer of pigment epithelium (PE) lines the iris PE (IPE), ciliary body PE, and retina PE of the inner eye, an immune-privileged site. These neural crest-derived epithelial cells participate in ocular immune privilege through poorly defined molecular mechanisms. Murine PE cells cultured from different ocular tissues suppress T cell activation by differing mechanisms. In particular, IPE cells suppress primarily via direct cell to cell contact. By examining surface expression of numerous candidate molecules (tumor necrosis factor receptor [TNFR]1, TNFR2, CD36, CD40, CD47, CD80, CD86, PD-L1, CD95 ligand, and type I interferon receptor), we report that IPE cells uniquely express on their surface the costimulatory molecule CD86. When IPE were blocked with anti-CD86 or were derived from CD80/CD86 (but not CD80) knockout (KO) mice, the cells displayed reduced capacity to suppress T cell activation. IPE also failed to suppress activation of T cells in the presence of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) immunoglobulin or if the T cells were obtained from CTLA-4 (but not CD28) KO mice. We conclude that iris pigment epithelial cells constitutively express cell surface CD86, which enables the cells to contact inhibit T cells via direct interaction with CTLA-4. Thus, ocular immune privilege is achieved in part by subversion of molecules that are usually used for conventional immune costimulation.

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Detection of mRNA expression of costimulatory molecules in ocular PE. mRNA, extracted from cultured IPE, CBPE, and RPE cells with or without 100 U/ml recombinant IFN-γ (samples 1–6), and from freshly obtained mouse iris, ciliary body, and retina (samples 7–9), was reverse transcribed and amplified by PCR using primers for (A) CD80 (B7-1), (B) CD86 (B7-2), (C) PD-L1 (B7-H1), (D) CD40, and (E) GAPDH. PCR products were electrophoresed in 1.5% agarose gel and visualized by staining with ethidium bromide.
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fig5: Detection of mRNA expression of costimulatory molecules in ocular PE. mRNA, extracted from cultured IPE, CBPE, and RPE cells with or without 100 U/ml recombinant IFN-γ (samples 1–6), and from freshly obtained mouse iris, ciliary body, and retina (samples 7–9), was reverse transcribed and amplified by PCR using primers for (A) CD80 (B7-1), (B) CD86 (B7-2), (C) PD-L1 (B7-H1), (D) CD40, and (E) GAPDH. PCR products were electrophoresed in 1.5% agarose gel and visualized by staining with ethidium bromide.

Mentions: Cells cultured from living tissues offer a convenient approach to the study of those tissues, but cultured cells often express molecules and adopt functional properties that are at variance with the intact tissue. We wished next to determine whether CD80 and CD86 are expressed on PE cells freshly obtained from iris, ciliary body, and retina. To that end, iris, ciliary body, and retina were harvested separately from eyes of adult mice. PE cells cultured from all three ocular tissues for 14 d were also prepared. mRNA was extracted from each of these tissue samples and from cultured cells, and then subjected to RT-PCR with primers for CD80 (Fig. 5 A), CD86 (B), PD-L1 (C), CD40 (D), or GAPDH (E). As revealed in Fig. 5, transcripts of CD80 and CD86 were detected in freshly obtained iris tissues. Transcripts for CD40 and PD-L1 were not detected in any ocular tissues containing PE or in cultured PE cells. However, transcripts for PD-L1 were inducibly detected in IFNγ-treated PE cells (Fig. 5 C). These results confirm that the genes for the costimulatory molecules CD80 and CD86 are open in both fresh and cultured PE cells. To further explore the expression of CD80 and CD86 in noncultured ocular tissues, frozen sections were prepared from eyes of C57BL/6 and BALB/c mice and subjected to immunohistochemical analysis using reagents that detect CD80 and CD86. As summarized in Table I, CD86 was detected in corneal epithelium (but not endothelium) in iris, ciliary body, lens, and RPE (but not in neural retina). A similar distribution pattern was observed for CD80, although the intensity of CD80 staining was much lower in epithelium of cornea and lens. The pattern of CD80 and CD86 expression on freshly obtained normal ocular tissues implies that expression of these costimulatory molecules is constitutive.


Iris pigment epithelium expressing CD86 (B7-2) directly suppresses T cell activation in vitro via binding to cytotoxic T lymphocyte-associated antigen 4.

Sugita S, Streilein JW - J. Exp. Med. (2003)

Detection of mRNA expression of costimulatory molecules in ocular PE. mRNA, extracted from cultured IPE, CBPE, and RPE cells with or without 100 U/ml recombinant IFN-γ (samples 1–6), and from freshly obtained mouse iris, ciliary body, and retina (samples 7–9), was reverse transcribed and amplified by PCR using primers for (A) CD80 (B7-1), (B) CD86 (B7-2), (C) PD-L1 (B7-H1), (D) CD40, and (E) GAPDH. PCR products were electrophoresed in 1.5% agarose gel and visualized by staining with ethidium bromide.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2196085&req=5

fig5: Detection of mRNA expression of costimulatory molecules in ocular PE. mRNA, extracted from cultured IPE, CBPE, and RPE cells with or without 100 U/ml recombinant IFN-γ (samples 1–6), and from freshly obtained mouse iris, ciliary body, and retina (samples 7–9), was reverse transcribed and amplified by PCR using primers for (A) CD80 (B7-1), (B) CD86 (B7-2), (C) PD-L1 (B7-H1), (D) CD40, and (E) GAPDH. PCR products were electrophoresed in 1.5% agarose gel and visualized by staining with ethidium bromide.
Mentions: Cells cultured from living tissues offer a convenient approach to the study of those tissues, but cultured cells often express molecules and adopt functional properties that are at variance with the intact tissue. We wished next to determine whether CD80 and CD86 are expressed on PE cells freshly obtained from iris, ciliary body, and retina. To that end, iris, ciliary body, and retina were harvested separately from eyes of adult mice. PE cells cultured from all three ocular tissues for 14 d were also prepared. mRNA was extracted from each of these tissue samples and from cultured cells, and then subjected to RT-PCR with primers for CD80 (Fig. 5 A), CD86 (B), PD-L1 (C), CD40 (D), or GAPDH (E). As revealed in Fig. 5, transcripts of CD80 and CD86 were detected in freshly obtained iris tissues. Transcripts for CD40 and PD-L1 were not detected in any ocular tissues containing PE or in cultured PE cells. However, transcripts for PD-L1 were inducibly detected in IFNγ-treated PE cells (Fig. 5 C). These results confirm that the genes for the costimulatory molecules CD80 and CD86 are open in both fresh and cultured PE cells. To further explore the expression of CD80 and CD86 in noncultured ocular tissues, frozen sections were prepared from eyes of C57BL/6 and BALB/c mice and subjected to immunohistochemical analysis using reagents that detect CD80 and CD86. As summarized in Table I, CD86 was detected in corneal epithelium (but not endothelium) in iris, ciliary body, lens, and RPE (but not in neural retina). A similar distribution pattern was observed for CD80, although the intensity of CD80 staining was much lower in epithelium of cornea and lens. The pattern of CD80 and CD86 expression on freshly obtained normal ocular tissues implies that expression of these costimulatory molecules is constitutive.

Bottom Line: When IPE were blocked with anti-CD86 or were derived from CD80/CD86 (but not CD80) knockout (KO) mice, the cells displayed reduced capacity to suppress T cell activation.IPE also failed to suppress activation of T cells in the presence of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) immunoglobulin or if the T cells were obtained from CTLA-4 (but not CD28) KO mice.Thus, ocular immune privilege is achieved in part by subversion of molecules that are usually used for conventional immune costimulation.

View Article: PubMed Central - PubMed

Affiliation: Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.

ABSTRACT
A monolayer of pigment epithelium (PE) lines the iris PE (IPE), ciliary body PE, and retina PE of the inner eye, an immune-privileged site. These neural crest-derived epithelial cells participate in ocular immune privilege through poorly defined molecular mechanisms. Murine PE cells cultured from different ocular tissues suppress T cell activation by differing mechanisms. In particular, IPE cells suppress primarily via direct cell to cell contact. By examining surface expression of numerous candidate molecules (tumor necrosis factor receptor [TNFR]1, TNFR2, CD36, CD40, CD47, CD80, CD86, PD-L1, CD95 ligand, and type I interferon receptor), we report that IPE cells uniquely express on their surface the costimulatory molecule CD86. When IPE were blocked with anti-CD86 or were derived from CD80/CD86 (but not CD80) knockout (KO) mice, the cells displayed reduced capacity to suppress T cell activation. IPE also failed to suppress activation of T cells in the presence of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) immunoglobulin or if the T cells were obtained from CTLA-4 (but not CD28) KO mice. We conclude that iris pigment epithelial cells constitutively express cell surface CD86, which enables the cells to contact inhibit T cells via direct interaction with CTLA-4. Thus, ocular immune privilege is achieved in part by subversion of molecules that are usually used for conventional immune costimulation.

Show MeSH
Related in: MedlinePlus