Limits...
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: 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.

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

Capacity of neutralizing antibodies to CD80 and CD86 to prevent suppression of T cell activation by cultured PE cells. Anti-CD3 stimulation of purified C57BL/6 T cells was performed as described in the legend to Fig. 1. Cultured IPE (A), CBPE (B), or RPE cells (C) were added in the presence or absence of 1 μg/ml anti-CD80 and/or anti-CD86 antibodies. As isotype controls, purified hamster IgG for CD80 and purified rat IgG for CD86 were used. After 72 h of incubation, the cultures were assayed for uptake of [3H]thymidine. Mean counts per minute for triplicate cultures are presented ± SEM. Differences of means of T cell proliferation in the presence of PE cells with and without anti-CD80 or anti-CD86 antibodies are compared. *, P < 0.05; **, P < 0.005.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2196085&req=5

fig3: Capacity of neutralizing antibodies to CD80 and CD86 to prevent suppression of T cell activation by cultured PE cells. Anti-CD3 stimulation of purified C57BL/6 T cells was performed as described in the legend to Fig. 1. Cultured IPE (A), CBPE (B), or RPE cells (C) were added in the presence or absence of 1 μg/ml anti-CD80 and/or anti-CD86 antibodies. As isotype controls, purified hamster IgG for CD80 and purified rat IgG for CD86 were used. After 72 h of incubation, the cultures were assayed for uptake of [3H]thymidine. Mean counts per minute for triplicate cultures are presented ± SEM. Differences of means of T cell proliferation in the presence of PE cells with and without anti-CD80 or anti-CD86 antibodies are compared. *, P < 0.05; **, P < 0.005.

Mentions: To determine whether CD80 and/or CD86 is involved in suppression of T cell activation by IPE cells, anti–CD3-driven T cell activation cultures were performed in wells containing a monolayer of cultured IPE, CBPE, or RPE as described above. In some wells, anti-CD80 or anti-CD86 antibodies were added alone or in combination. T cell proliferation was assessed as before, and the results are displayed in Fig. 3. In cultures containing IPE plus anti-CD86 antibodies alone, or anti-CD80/anti-CD86 antibodies, T cell proliferation was significantly greater than in cultures to which isotype control antibodies were added (Fig. 3 A). In cultures containing IPE plus anti-CD80 antibodies alone, a small increase in T cell proliferation was observed. By contrast, neither anti-CD80 nor anti-CD86 antibodies relieved the profound suppression observed in cultures in which T cells were exposed to CBPE (Fig. 3 B) or RPE (Fig. 3 C). Parallel experiments conducted with ocular PE harvested from BALB/c mice yielded similar results (not depicted). These findings support the hypothesis that IPE suppress T cell activation via a CD86-dependent mechanism. The results bearing on a comparable role for CD80 are less impressive, although CD80 cannot on the basis of these findings be excluded from participating in IPE-dependent T cell suppression. Anti-CD86 antibodies did not reverse completely the suppression mediated by IPE, even when higher antibody concentrations were used. We infer that IPE use surface molecules in addition to CD86 in mediating suppression of T cell activation.


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)

Capacity of neutralizing antibodies to CD80 and CD86 to prevent suppression of T cell activation by cultured PE cells. Anti-CD3 stimulation of purified C57BL/6 T cells was performed as described in the legend to Fig. 1. Cultured IPE (A), CBPE (B), or RPE cells (C) were added in the presence or absence of 1 μg/ml anti-CD80 and/or anti-CD86 antibodies. As isotype controls, purified hamster IgG for CD80 and purified rat IgG for CD86 were used. After 72 h of incubation, the cultures were assayed for uptake of [3H]thymidine. Mean counts per minute for triplicate cultures are presented ± SEM. Differences of means of T cell proliferation in the presence of PE cells with and without anti-CD80 or anti-CD86 antibodies are compared. *, P < 0.05; **, P < 0.005.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196085&req=5

fig3: Capacity of neutralizing antibodies to CD80 and CD86 to prevent suppression of T cell activation by cultured PE cells. Anti-CD3 stimulation of purified C57BL/6 T cells was performed as described in the legend to Fig. 1. Cultured IPE (A), CBPE (B), or RPE cells (C) were added in the presence or absence of 1 μg/ml anti-CD80 and/or anti-CD86 antibodies. As isotype controls, purified hamster IgG for CD80 and purified rat IgG for CD86 were used. After 72 h of incubation, the cultures were assayed for uptake of [3H]thymidine. Mean counts per minute for triplicate cultures are presented ± SEM. Differences of means of T cell proliferation in the presence of PE cells with and without anti-CD80 or anti-CD86 antibodies are compared. *, P < 0.05; **, P < 0.005.
Mentions: To determine whether CD80 and/or CD86 is involved in suppression of T cell activation by IPE cells, anti–CD3-driven T cell activation cultures were performed in wells containing a monolayer of cultured IPE, CBPE, or RPE as described above. In some wells, anti-CD80 or anti-CD86 antibodies were added alone or in combination. T cell proliferation was assessed as before, and the results are displayed in Fig. 3. In cultures containing IPE plus anti-CD86 antibodies alone, or anti-CD80/anti-CD86 antibodies, T cell proliferation was significantly greater than in cultures to which isotype control antibodies were added (Fig. 3 A). In cultures containing IPE plus anti-CD80 antibodies alone, a small increase in T cell proliferation was observed. By contrast, neither anti-CD80 nor anti-CD86 antibodies relieved the profound suppression observed in cultures in which T cells were exposed to CBPE (Fig. 3 B) or RPE (Fig. 3 C). Parallel experiments conducted with ocular PE harvested from BALB/c mice yielded similar results (not depicted). These findings support the hypothesis that IPE suppress T cell activation via a CD86-dependent mechanism. The results bearing on a comparable role for CD80 are less impressive, although CD80 cannot on the basis of these findings be excluded from participating in IPE-dependent T cell suppression. Anti-CD86 antibodies did not reverse completely the suppression mediated by IPE, even when higher antibody concentrations were used. We infer that IPE use surface molecules in addition to CD86 in mediating suppression of T cell activation.

Bottom Line: 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.

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