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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 B7 molecules on cultured PE cells by flow cytometry. IPE (BALB/c and C57BL/6), CBPE (C57BL/6), and RPE cells (C57BL/6) were cultured on 6-well plates for 14 d. Thereafter, the confluent cells were triturated several times through 21-gauge and then 23-gauge needles to create a single cell suspension. PE cells were incubated with FITC-conjugated antibodies: anti-CD80, anti-CD86, or purified hamster IgG as isotype control for 1 h at room temperature. After washing and fixation, the cells were analyzed by flow cytometry. Percentages in upper right corners indicate positive cells. Number in parenthesis indicate mean fluorescence index.
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fig4: Detection of B7 molecules on cultured PE cells by flow cytometry. IPE (BALB/c and C57BL/6), CBPE (C57BL/6), and RPE cells (C57BL/6) were cultured on 6-well plates for 14 d. Thereafter, the confluent cells were triturated several times through 21-gauge and then 23-gauge needles to create a single cell suspension. PE cells were incubated with FITC-conjugated antibodies: anti-CD80, anti-CD86, or purified hamster IgG as isotype control for 1 h at room temperature. After washing and fixation, the cells were analyzed by flow cytometry. Percentages in upper right corners indicate positive cells. Number in parenthesis indicate mean fluorescence index.

Mentions: Because cultured PE cells expressed transcripts for CD80 and/or CD86, and because antibodies directed at CD86 partially alleviated the suppression mediated by IPE, we next examined by flow cytometry the extent to which cultured PE cells expressed CD80 and CD86. After 14 d of primary culture, IPE, CBPE, and RPE cells were harvested and labeled with FITC-conjugated antibodies directed at CD80 or CD86, and were analyzed by flow cytometry. The results of a representative experiment (of two) are presented in Fig. 4. CD80 was expressed on the majority of cultured IPE and CBPE, as well as on a large minority of RPE cells. By contrast, CD86 was expressed on a very high proportion of IPE cells, but on far fewer CBPE and RPE cells. The hypothesis that IPE cells mediate suppression of T cell activation via a CD86-dependent contact mechanism is supported by these data.


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 B7 molecules on cultured PE cells by flow cytometry. IPE (BALB/c and C57BL/6), CBPE (C57BL/6), and RPE cells (C57BL/6) were cultured on 6-well plates for 14 d. Thereafter, the confluent cells were triturated several times through 21-gauge and then 23-gauge needles to create a single cell suspension. PE cells were incubated with FITC-conjugated antibodies: anti-CD80, anti-CD86, or purified hamster IgG as isotype control for 1 h at room temperature. After washing and fixation, the cells were analyzed by flow cytometry. Percentages in upper right corners indicate positive cells. Number in parenthesis indicate mean fluorescence index.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2196085&req=5

fig4: Detection of B7 molecules on cultured PE cells by flow cytometry. IPE (BALB/c and C57BL/6), CBPE (C57BL/6), and RPE cells (C57BL/6) were cultured on 6-well plates for 14 d. Thereafter, the confluent cells were triturated several times through 21-gauge and then 23-gauge needles to create a single cell suspension. PE cells were incubated with FITC-conjugated antibodies: anti-CD80, anti-CD86, or purified hamster IgG as isotype control for 1 h at room temperature. After washing and fixation, the cells were analyzed by flow cytometry. Percentages in upper right corners indicate positive cells. Number in parenthesis indicate mean fluorescence index.
Mentions: Because cultured PE cells expressed transcripts for CD80 and/or CD86, and because antibodies directed at CD86 partially alleviated the suppression mediated by IPE, we next examined by flow cytometry the extent to which cultured PE cells expressed CD80 and CD86. After 14 d of primary culture, IPE, CBPE, and RPE cells were harvested and labeled with FITC-conjugated antibodies directed at CD80 or CD86, and were analyzed by flow cytometry. The results of a representative experiment (of two) are presented in Fig. 4. CD80 was expressed on the majority of cultured IPE and CBPE, as well as on a large minority of RPE cells. By contrast, CD86 was expressed on a very high proportion of IPE cells, but on far fewer CBPE and RPE cells. The hypothesis that IPE cells mediate suppression of T cell activation via a CD86-dependent contact mechanism is supported by these data.

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