Soluble MHC class II-driven therapy for a systemic lupus erythematosus murine experimental in vitro and in vivo model

Cucurbitacin IIb improved active chromatin-induced systemic lupus erythematosus via balancing the percentage of Th17 and Treg cells

The pathogenesis of systemic lupus erythematosus (SLE) is closely associated with aberrant immune system. Here, the aim of our study was to explore the regulation of cucurbitacin IIb (CuIIb) to Th17/Treg cells in SLE. Compared with normal mice, the percentage of Treg cells was downregulated in SLE mouse model, and Th17 was upregulated. Meantime, the production of Treg-related transcription factor (foxp3) in SLE model mouse was reduced, and the production of Th17-related transcription factor (RORγt) was increased. After treatment with CuIIb, the percentage of Treg cells in SLE mice was partly upregulated, and Th17 cells percentage was downregulated. The expression of foxp3 and RORγt in SLE mice were promoted and inhibited by CuIIb treatment, respectively. SLE-induced kidney injury also was improved by CuIIb treatment. In vitro, we demonstrated again that CuIIb upregulated the percentage of Treg cells in lymphocytes from SLE mice, and downregulated the percentage of Th17 cells. Highly expressed IL-6 and IL17, and lowly expressed IL-10 and TGF-β in lymphocytes from SLE mice were repressed and facilitated by CuIIb treatment, respectively. Overall, our data proved that CuIIb improved kidney injury in SLE mice through balancing the percentage of Th17 and Treg cells. Our data provided a reliable evidence to support the potential of CuIIb in SLE treatment.

The Potential of Soluble Human Leukocyte Antigen Molecules for Early Cancer Detection and Therapeutic Vaccine Design

Human leukocyte antigen (HLA) molecules are essential for anti-tumor immunity, as they display tumor-derived peptides to drive tumor eradication by cytotoxic T lymphocytes. HLA molecules are primarily studied as peptide-loaded complexes on cell membranes (mHLA) and much less attention is given to their secretion as soluble HLA–peptide complexes (sHLA) into bodily fluids. Yet sHLA levels are altered in various pathologies including cancer, and are thus of high interest as biomarkers. Disconcordance in results across studies, however, hampers interpretation and generalization of the relationship between sHLA levels and cancer presence, thereby impairing its use as a biomarker. Furthermore, the question remains to what extent sHLA complexes exert immunomodulatory effects and whether shifts in sHLA levels contribute to disease or are only a consequence of disease. sHLA complexes can also bear tumor-derived peptides and recent advancements in mass spectrometry now permit closer sHLA peptide cargo analysis. sHLA peptide cargo may represent a “liquid biopsy” that could facilitate the use of sHLA for cancer diagnosis and target identification for therapeutic vaccination. This review aims to outline the contradictory and unexplored aspects of sHLA and to provide direction on how the full potential of sHLA as a quantitative and qualitative biomarker can be exploited.

Rescue of autoimmune hepatitis by soluble MHC class II molecules in an altered concanavalin A-induced experimental model

BACKGROUND

Soluble major histocompatibility complex class II (sMHCII) molecules have been described to maintain tolerance through the suppression of autoreactive T lymphocytes. In order to evaluate their ability to rescue autoimmune hepatitis (AIH) symptoms, the present work attempted to administer sMHCII molecules to an in vitro as well as in vivo concanavalin A (ConA)-induced AIH model.

METHODS

The in vitro AIH model consisted of splenocyte stimulation with ConA in the presence or absence of serum-isolated sMHCII molecules. An in vivo ConA-modified model with or without sMHCII treatment was developed. The cytokine profile in culture supernatants and serum was tested by ELISA. Cell markers were evaluated by immunofluorescence, while cell proliferation by tritiated thymidine uptake. AIH symptoms were assessed by daily observations for the establishment of a disease severity scoring system and liver histology was evaluated using a biomolecular imager.

RESULTS

The presence of sMHCII molecules in the ConA-stimulated cell cultures leads to a significant reduction of cell proliferation. The administration of sMHCII molecules to the ConA-treated animals showed a significant reduction in the levels of IL-2, IL-4, and IL-10, as well as a decrease in the number of spleen CD4+ and CD8+ cells. Upon development of a scoring system, it was shown that the sMHCII treatment was accompanied by a slower progression of the disease, while rescuing fibrotic liver morphology.

CONCLUSION

The results presented in this study confirm the ability of sMHCII proteins to alleviate autoimmune hepatitis, possibly highlighting new therapeutic approaches for autoimmune diseases.

Invariant chain p41 mediates production of soluble MHC class II molecules

Major histocompatibility complex class II (MHC II) molecules are mainly expressed on antigen presentation cells and play an important role in immune response. It has been reported that MHC II molecules are also detected in serum as a soluble form (sMHC II molecules), and they are considered to be involved in the maintenance of self-tolerance. However, the mechanism by which sMHC II molecules are produced remains unclear. Invariant chain (Ii), also called CD74, plays an important role in antigen presentation of MHC II molecules. In the present study, we analyzed the role of Ii on the production of sMHC II molecules. We found that the amount of sMHC II molecules in serum was decreased in Ii-deficient mice compared to wild-type mice. sMHC II molecules were secreted from cells transfected with MHC II molecules and Ii but not from cells transfected with MHC II molecules alone. Moreover, isoform p41 of Ii-transfected cells induced more sMHC II molecules compared to isoform p31-transfected cells. The molecular weight of sMHC II molecules from MHC II and Ii p41-transfected cells was approximately 60 kDa, indicating that sMHC II molecules are a single heterodimer of α and β chains that is not associated with micro-vesicles. From the analysis of Ii-deletion mutants, we found that the luminal domain of Ii p41 is crucial for the production of sMHC II molecules. These results suggested that Ii has an important role in production of sMHC II molecules.