[Expression of SSA antigen epitopes in minor salivary glands from patients with primary Sjögren's syndrome].
OBJECTIVE
To investigate the correlation between the differential expression of 60 000 SSA epitopes in minor salivary glands (MSG) from patients with primary Sjögren's syndrome (pSS) and glandular inflammation.


METHODS
The screening and soluble expression of single-chain fragment V monoclonal antibodies (Scfv McAb) against SSA antigen epitopes (P1: 480 - 494, P2: 310 - 323 and P3: 230 - 241) were performed by phagemid antibody expression system. The expression of epitopes was detected by immunohistochemical assay (IH) in minor salivary glands from these patients. The correlation between epitopes expression and glandular inflammation was analyzed quantitatively.


RESULTS
Immunohistochemical assay of MSG with McAb against P1-P3 epitopes showed that the epithelial cells of glandular tubes and striated duct were stained in membrane and cytoplasm. The expression of P1 epitope was higher than the other two in grading score (chi(2) = 12.94, P < 0.01). And a positive correlation was found between the extent of glandular infiltration and the grade of P1 epitope expression (t = 2.27, P < 0.05) but not with P2 or P3 epitope.


CONCLUSIONS
Aberrant redistribution of intracellular SSA antigen epitopes onto the cell membrane of involved cells may break the immune tolerance and thus induce the production of pathogenic autoantibodies involved in triggering and maintaining the tissue-specific autoimmune response in pSS MSG. A significantly high membranous expression of P1 and a positive correlation between P1 and the inflammation of MSG suggest that P1 may be the dominant determinant of the antigen-driven immune response in pSS.
Li
Hong-bin
HB
Department of Rheumatology, Peking Union Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China.
Zhang
Feng-chun
FC
Zhang
Xuan
X
Gan
Xiao-dan
XD
Shi
Yan-ping
YP
Bai
Yi-na
YN
Tang
Fu-lin
FL
D000911:Antibodies, Monoclonal / Q000276:immunology; D000939:Epitopes / Q000276:immunology*; D006801:Humans; D012261:Ribonucleoproteins / Q000276:immunology*; D012470:Salivary Glands, Minor / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D057127:Single-Chain Antibodies / Q000276:immunology; D012859:Sjogren's Syndrome / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D000099207:SS-A Antigen
D000911:Antibodies, Monoclonal; D000939:Epitopes; D012261:Ribonucleoproteins; D057127:Single-Chain Antibodies; D000099207:SS-A Antigen