Retinal S-antigen Th1 cell epitope mapping in patients with Behcet's disease.
BACKGROUND
Retinal S-antigen (S-Ag) is a most characterized autoantigen of autoimmune uveitis. The recognized immunodominant epitope of human S-Ag in patients with uveitis has not been identified. In this study, we selected certain patients with active uveitis to map the Th1 cell epitope spectrum of human S-Ag in Behcet's disease(BD).


METHODS
Blood samples were taken from eight active BD patients who showed an immune response to 40 mixed overlapping peptides spanning the entire sequence of human S-Ag. Peripheral blood mononuclear cells were isolated and stimulated with single S-Ag peptide at 5 microg/ml or 20 microg/ml. Single-cell immune responses were measured by IFN-gamma ELIspot assay.


RESULTS
BD patients heterogeneously responded to the S-Ag peptides at two concentrations. In general, the responses to 5 microg/ml peptides were slightly stronger than those to 20 microg/ml peptides, while the maximum SFC frequency to single peptide at the two concentrations was similar. Several peptides including P31, P35 and P40 induced a prominent response, with the frequency of S-Ag specific cells being about 0.007%. Significant reactivity pattern shift was noted in patients with different disease courses.


CONCLUSIONS
Certain active BD patients have S-Ag specific Th1 cells with a low frequency. The S-Ag epitope specificity between patients is highly heterogeneous, and varies with the uveitis course.
Zhao
Changlin
C
Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, People's Republic of China.
Yang
Peizeng
P
He
Hao
H
Lin
Xiaomin
X
Du
Liping
L
Zhou
Hongyan
H
Kijlstra
Aize
A
D000328:Adult; D000595:Amino Acid Sequence; D019393:Arrestin / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology*; D001528:Behcet Syndrome / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D018604:Epitope Mapping; D006801:Humans; D007111:Immunity, Cellular; D016056:Immunodominant Epitopes / Q000276:immunology*; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology*
D019393:Arrestin; D001324:Autoantigens; D016056:Immunodominant Epitopes; D010446:Peptide Fragments