Expression of B7 costimulatory molecules by salivary gland epithelial cells in patients with Sj�gren's syndrome

Abstract

Objective. To investigate the expression of B7 costimulatory molecules in the lymphoepithelial lesions of salivary gland (SG) biopsy tissues and in SG epithe-lial cell lines derived from patients with Sjögren's syndrome (SS). Methods. B7.1 and B7.2 protein expression was studied by immunohistochemistry in minor SGs obtained from 11 patients with SS and 10 disease control patients with nonspecific sialadenitis and in cultured SG epithelial cell lines obtained from minor SGs from 15 SS patients and 15 control patients. B7.1 and B7.2 messenger RNA (mRNA) expression by SG epithelial cell lines was examined by reverse transcription-polymerase chain reaction (RT-PCR). Results. In biopsy tissues from SS patients, but not control patients, ductal and acinar epithelial cells showed increased expression of both B7.1 and B7.2. Intense spontaneous B7.1 protein expression (as well as HLA-ABC, but not B7.2 or HLA-DR) was also found in 73% of SG epithelial cell lines from SS patients versus 13% of those from control patients (P < 0.01). Interferon-treatment induced, or up-regulated, B7.1, B7.2, and HLA-DR expression in all SG epithelial cell lines tested. B7.1 and B7.2 expression by SG epithelial cell lines was also verified at the mRNA level by RT-PCR. Conclusion. Human SG epithelia are intrinsically capable of expressing B7 proteins upon activation. In SS patients, the expression of B7 molecules by SG epithe-lial tissues and by SG epithelial cell lines indicates the activated status of SG epithelial cells in this disorder and, possibly, their capacity for presenting antigens to T cells.

Functional Expression of a Costimulatory B7.2 (CD86) Protein on Human Salivary Gland Epithelial Cells that Interacts with the CD28 Receptor, but Has Reduced Binding to CTLA4

“…All cultures were incubated at 37°C, 5% CO 2 , and 99% humidity. The epithelial origin of SGEC lines was routinely verified immunocytochemically by the expression of epithelialspecific cell markers such as cytokeratins, as previously described (31). SGEC cultures were free of T and B cells, macrophages, and dendritic cells, as indicated by the absent expression of such cell type-specific markers (data not shown).…”

“…SS was diagnosed on the basis of the European SS classification criteria (32). Nonneoplastic long-term SGEC cultures were developed, characterized, and maintained, as previously described (31). Briefly, primary cultures were established by explant outgrowth technique in a medium consisting of a 3:1 mixture Ham's F12 and DMEM (Life Technologies) supplemented with 2.5% FBS (Life Technologies), 0.4 g/ml hydrocortisone (Upjohn, Kalamazoo, MI), 0.125 U/ml insulin (Novo, Bagsvaerd, Denmark), 10 ng/ml epidermal growth factor (Promega, Madison, WI), 2 mM glutamine, 100 U/ml penicillin, and 100 g/ml streptomycin.…”

“…Cultured SGEC grown in multichamber slides were analyzed by immunocytochemistry using the avidin-biotin immunoperoxidase technique, as previously described (31).…”

“…Recently, using biopsy specimens and cultured nonneoplastic cell lines derived from patients with Sjögren's syndrome (SS), 3 we have presented evidence for the expression of B7.1 and B7.2 molecules by salivary gland epithelial cells (SGEC) at both the mRNA and the protein level (31). In fact, increased spontaneous expression of a BB1 mAb-reactive protein was demonstrated in SGEC lines.…”

Antagonist of interferon‐inducible protein 10/CXCL10 ameliorates the progression of autoimmune sialadenitis in MRL/lpr mice

“…Several investigators have suggested that polarized Th1 balance is associated with the pathogenesis of SS (35)(36)(37). IFN␥ induces expression of HLA-DR and costimulatory molecules such as CD40 and B7 on salivary epithelial cells, resulting in the promotion of autoimmune reactions between epithelial cells and lymphocytes (38)(39)(40). In addition, the Th1-associated chemokines IP-10, Mig, and I-TAC have been reported to be predominantly expressed in the ductal epithelium, leading to the accumulation of T cell infiltrates in the salivary glands of patients with SS (8,9).…”