Anti-STAT4 (full length) polyclonal antibody

Natural killer (NK) cells are innate immune cells that interface with the adaptive immune system to generate a pro-inflammatory immune environment. Primary Biliary Cholangitis (PBC) is a hepatic autoimmune disorder with extrahepatic associations including systemic sclerosis, Sjogren's syndrome and thyroiditis. Immunogenetic studies have identified polymorphisms of the IL-12/STAT4 pathway as being associated with PBC. As this pathway is important for NK cell function we investigated NK cells in PBC. Circulating NK cells from individuals with PBC were constitutively activated, with higher levels of CD49a and the liver-homing marker, CXCR6, compared to participants with non-autoimmune chronic liver disease and healthy controls. Stimulation with minimal amounts of IL-12 (0.005 ng/ml) led to significant upregulation of CXCR6 (p < 0.005), and enhanced IFN gamma production (p < 0.02) on NK cells from PBC patients compared to individuals with non-autoimmune chronic liver disease, indicating dysregulation of the IL-12/STAT4 axis. In RNAseq studies, resting NK cells from PBC patients had a constitutively activated transcriptional profile and upregulation of genes associated with IL-12/STAT4 signaling and metabolic reprogramming. Consistent with these findings, resting NK cells from PBC patients expressed higher levels of pSTAT4 compared to control groups (p < 0.001 vs. healthy controls and p < 0.05 vs. liver disease controls). In conclusion NK cells in PBC are sensitive to minute quantities of IL-12 and have a "primed" phenotype. We therefore propose that peripheral priming of NK cells to express tissue-homing markers may contribute to the pathophysiology of PBC.

Most studies of xenografts have been carried out with complex immunosuppressive regimens to prevent immune rejection; however, such treatments may be fatal owing to unknown causes. Here, we performed immune molecular profiling following anti-CD154 monoclonal antibody (mAb) treatment in heterotopic abdominal cardiac xenografts from -1,3-galactosyltransferase-knockout pigs into cynomolgus monkeys to elucidate the mechanisms mediating the undesirable fatal side effects of immunosuppressive agents. Blood samples were collected from healthy monkeys as control and then at 2days after xenograft transplantation and just before humane euthanasia; 94 genes related to the immune system were analyzed. The basic immunosuppressive regimen included cobra venom factor, anti-thymocyte globulin, and rituximab, with and without anti-CD154 mAbs. The maintenance therapy was followed with tacrolimus, MMF, and methylprednisolone. The number of upregulated genes was initially decreased on Day 2 (-/+ anti-CD154 mAb, 22/13) and then increased before euthanasia in recipients treated with anti-CD154 mAbs (-/+ anti-CD154 mAb, 30/37). The number of downregulated genes was not affected by anti-CD154 mAb treatment. Additionally, the number of upregulated genes increased over time for both groups. Interestingly, treatment with anti-CD154 mAbs upregulated coagulation inducers (CCL2/IL6) before euthanasia. In conclusion, immunosuppressive regimens used for cardiac xenografting affected upregulation of 6 inflammation genes (CXCL10, MPO, MYD88, NLRP3, TNF, and TLR1) and downregulation of 8 genes (CCR4, CCR6, CD40, CXCR3, FOXP3, GATA3, STAT4, and TBX21).