Metabolic-associated steatohepatitis (MASH) and pancreatic inflammation are key complications of obesity-related metabolic syndrome. Elevated IL-6; a proinflammatory cytokine, contributes to liver steatosis and pancreatic β-islet cells dysfunction. This study explores pancreatic tissue-resident (tr)NK cells IL-6 receptor (IL-6R) in pancreatic injury in a murine MASH model.
MASH models were established using male Ob/Ob mice fed a high-fat diet (Ob/Ob HFD; 60.3% kcal from fat) for 4 weeks and using immunocompromised NOD-SCID IL2rγnull (NSG) mice fed with HFD for 16 weeks and i.v. injected with 10 × 106 pancreatic trNK and treated with IL-6R antagonizing antibody on week 12. Biochemical assays assessed serum ALT, AST, lipids, glucose, and insulin levels. Pancreatic injury was analyzed through mRNA expression of Reg1, Reg3, oxidative stress marker of tissue malondialdehyde (MDA) and β-islet cells' proliferation and apoptosis. Fibrotic markers of α-SMA, Collagen-I, and Fibronectin were assessed via RT-PCR and trNK cell activation (CD107a, NKp46, IFN-γ) were assessed by flow cytometry.
Ob/Ob HFD mice exhibited increased serum cholesterol, triglycerides, fasting blood glucose, and liver injury enzymes. Markers of pancreatic injury of Reg1/Reg3 and pancreatic MDA with β-islet cells apoptosis were significantly elevated compared to littermates' control. These results were accompanied by a decline in trNK counts and activations (P < 0.05). In an adoptive transfer model, NSG mice fed with HFD and transplanted with trNK cells from Ob/Ob HFD donors (expressing high IL-6) exhibited similar pancreatic injury markers, whereas those receiving trNK cells from Ob/Ob HFD mice pre-treated with an IL-6R antagonist showed marked reductions in Reg1/Reg3 (∼2-fold), MDA (∼1.77-fold), and β-islet cells apoptosis (∼2.2-fold). Moreover, phenotypic characterization of the NSG mice fed an HFD transplanted with IL-6R antagonizing antibody showed an increase in the NK cell activation marker CD107a (∼2.3-fold) and amelioration in pancreatic fibrotic profile of α-SMA mRNA expressions of 1.6 -fold when compared to its counterparts.
Our data highlights the importance of IL-6R modulation on trNK cells in remodeling pancreatic tissue after liver injury, emphasizing the liver-pancreas axis as a therapeutic target to prevent pancreatic damage, β-islet cells dysfunction and fibrosis and reduce the risk of diabetes and metabolic syndrome.
Copyright © 2025 Amer, Arra, Salhab, Kayed, Maali, Shweiki and Ghanim.

Prime-2-CoV_Beta is a novel Orf virus (ORFV)-based COVID-19 vaccine candidate expressing both the nucleocapsid and spike proteins of SARS-CoV-2 with the receptor-binding domain (RBD) of the Beta strain. This candidate was shown to be safe and immunogenic in a first-in-human Phase I clinical trial. With the shift in the immune landscape toward the Omicron variant and the widespread vaccine- and/or infection-derived immunity, further pre-clinical research was needed to characterize Prime-2-CoV. Here, we quantified the humoral and cellular response to Prime-2-CoV_Beta in pre-immunized mice and compared the protective efficacy of mono- and bivalent variant-based Prime-2-CoV vaccine candidates in hamsters. Prime-2-CoV_Beta induced robust humoral and cellular immune responses in naïve animals but did not further boost antibody titers in the tested setting when given as repeat booster at short interval. We furthermore showed that Prime-2-CoV_Beta-based mono- and bivalent immunization strategies produced comparable immunogenicity and protection from infection. Our results highlight the potential of the Orf virus as a vaccine platform against SARS-CoV-2 and potentially other infectious viruses.

Natural killer (NK) cells are important effectors of the innate immune system and participate in the first line of defense against infections and tumors. Prior to being functional, these lymphocytes must be educated or licensed through interactions of their major histocompatibility complex class I molecules with self-specific inhibitory receptors that recognize them. In the absence of such contacts, caused by either the lack of expression of the inhibitory receptors or a very low level of major histocompatibility complex class I (MHC class I) proteins, NK cells are hypo-reactive at baseline (ex vivo). After stimulation (assessed through plate-bound antibodies against activating receptors or culture in the presence of cytokines such as interleukin (IL)-2 or IL-15) however, they can become cytotoxic and produce cytokines. This is particularly the case in transporter associated with antigen processing (TAP)-deficient mice, which we investigated in the present study. Transporter associated with antigen processing transports endogenous peptides from the cytosol to the endoplasmic reticulum, where they are loaded on nascent MHC class I molecules, which then become stable and expressed at the cell surface. Consequently, TAP-KO mice have very low levels of MHC class I expression. We present a study about phenotypic and functional aspects of NK cells in two mouse strains, C57BL/6 wildtype and TAP1-KO in spleen and lung. We observed that in both types of mice, on the same genetic background, the initial pattern of education, conferred to the cells via the inhibitory receptors Ly49C/I and NKG2A, was maintained even after a strong stimulation by the cytokines interleukin-2, interleukin-12, interleukin-15 and interleukin-18. Furthermore, the percentages of activated NK cells expressing Ly49C/I and Ly49I were strongly down-modulated under these conditions. We completed our investigations with phenotypic studies of NK cells from these mice.
Copyright © 2022 Patil, Domingues, Masquelier, Theresine, Schlienger, Njinju Amin Asaba, Thomas, Seguin-Devaux, Slevogt, Ollert and Zimmer.