Immunoregulation by aqueous humor.
OBJECTIVE
The eye is a classic example of an immune-privileged site. To investigate the local defense system of the eye, the immunosuppressive effects of the aqueous humor on cytokine production was examined.


METHODS
Using T cell clones (TCCs) established from infiltrating cells in the aqueous humor of patients with human T lymphotropic virus type 1 (HTLV-1) uveitis as target cells and the aqueous humor of patients with senile cataract obtained during cataract surgery, we examined the effects of the aqueous humor on the production of cytokines by HTLV-1-infected TCCs.


RESULTS
HTLV-1-infected TCCs produced large amounts of various cytokines. The aqueous humor inhibited the production of cytokines in a dose-dependent manner. The inhibitory activity was heat labile. First protein liquid chromatography showed at least four major peaks of different molecular size, indicating that the aqueous humor contains multiple immunosuppressive factors. Transforming growth factor-beta, alpha-melanocyte-stimulating hormone, and vasoactive intestinal peptide did not suppress cytokine production. The inhibitory activity was neutralized by monoclonal antibody to Fas ligand.


CONCLUSIONS
These data suggest that soluble Fas ligand is a candidate suppressive factor in the aqueous humor.
Mochizuki
M
M
Department of Visual Science, Tokyo Medical and Dental University Graduate School, Japan.
Sugita
S
S
Ishikawa
N
N
Watanabe
T
T
D001082:Aqueous Humor / Q000276:immunology*; D016207:Cytokines / Q000096:biosynthesis*; D053222:Fas Ligand Protein; D015490:HTLV-I Infections / Q000276:immunology; D015368:Human T-lymphotropic virus 1 / Q000502:physiology; D006801:Humans; D008024:Ligands; D008562:Membrane Glycoproteins / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology* / Q000821:virology; D014605:Uveitis / Q000821:virology; D019014:fas Receptor / Q000502:physiology
D016207:Cytokines; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008024:Ligands; D008562:Membrane Glycoproteins; D019014:fas Receptor