Sjögren’s syndrome (SS) is a female dominated autoimmune disease characterized by lymphocytic infiltration into salivary and lacrimal glands and subsequent exocrine glandular dysfunction. SS also may exhibit a broad array of extraglandular manifestations including an elevated incidence of non-Hodgkin’s B cell lymphoma. The etiology of SS remains poorly understood, yet progress has been made in identifying progressive stages of disease using preclinical mouse models. The roles played by immune cell subtypes within these stages of disease are becoming increasingly well understood, though significant gaps in knowledge still remain. There is evidence for distinct involvement from both innate and adaptive immune cells, where cells of the innate immune system establish a proinflammatory environment characterized by a type I interferon (IFN) signature that facilitates propagation of the disease by further activating T and B cell subsets to generate autoantibodies and participate in glandular destruction. This review will discuss the evidence for participation in disease pathogenesis by various classes of immune cells and glandular epithelial cells based upon data from both preclinical mouse models and human patients. Further examination of the contributions of glandular and immune cell subtypes to SS will be necessary to identify additional therapeutic targets that may lead to better management of the disease.

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Sjögren’s syndrome (SjS) is characterized by lymphocytic infiltration and the dysfunction of the salivary and lacrimal glands. The autoimmune response is driven by the effector T cells and their cytokines. The activation of the effector helper T cells is mediated by autoantigen presentation by human leukocyte antigen (HLA) class II molecules of antigen-presenting cells. Studies using familial aggregation, animal models, and genome-wide association demonstrate a significant genetic correlation between specific risk HLAs and SjS. One of the key HLA alleles is HLA-DRB1*0301; it is one of the most influential associations with primary SjS, having the highest odds ratio and occurrence across different ethnic groups. The specific autoantigens attributed to SjS remain elusive, especially the specific antigenic epitopes presented by HLA-DRB1*0301. This study applied a high throughput in silico mapping technique to identify antigenic epitopes of known SjS autoantigens presented by high-risk HLAs. Furthermore, we identified specific binding HLA-DRB1*0301 epitopes using structural modeling tools such as Immune Epitope Database and Analysis Resource IEDB, AutoDock Vina, and COOT. By deciphering the critical epitopes of autoantigens presented by HLA-DRB1*0301, we gain a better understanding of the origin of the antigens, determine the T cell receptor function, learn the mechanism of disease progression, and develop therapeutic applications.

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Sjogren’s Syndrome (SjS) is one of the more common autoimmune diseases that has a strong genetic linkage. To date, no vaccine or therapeutic exists to cure SjS, and patients must rely on lifelong therapies to treat symptoms. Class II MHC are the primary susceptibility loci that form the genetic basis for many auto-immune disorders including SjS. I-Ag7 is the MHC in NOD mice that is used for the presentation of autoantigens and plays a critical role in the adaptive immune response. HLA-DQ8 the MHC in humans, is analogous to I-Ag7, in the NOD mouse model and is an important model for the onset of SjS. Using an in-silico molecular docking program a chemical library was screened that defined small molecules that were capable of occupying specific structural pockets along the I-Ag7 binding groove, with the objective of influencing auto-antigen peptide presentation to T cells. In this study we show, that the small molecule TATD can inhibit TCR signaling based on the structural pocket targeting mechanism. TATD previously proven to inhibit the onset of diabetes by blocking the auto-antigen presentation on I-Ag7, was analyzed to observe effects of prevention of SjS by, preventing the accumulation of B and T cells within the salivary gland of NOD mice. Treated mice also showed reduction in the incidence of inflammatory cell infiltration into lacrimal and salivary glands as compared to control mice with notable reduction in of the hallmark SjS anti-nuclear antibodies of Ro52, Ro60 and La. As a result this study presents a novel method for identifying small molecules capable of inhibiting T cell responses, with potentially therapeutic applications.