Despite the advancements in vaccination research and practices, influenza viruses remain a global health concern. Inducing a robust immune response by vaccination is especially challenging in the elderly, the immunocompromised, and persons with chronic illnesses. Polysaccharides derived from food may act as a safe and readily accessible means to boost the immune system during vaccination. In this study, we investigated whether crude polysaccharides derived from carrot pomace (CPP) could stimulate innate immune cell function and promote influenza vaccine immunogenicity. In bone marrow-derived dendritic cells (BMDCs), CPP increased the fraction of CD11c+MHCII+ cells and the expression of co-stimulatory molecules CD40 and CD80, indicative of enhanced maturation and activation. Functionally, CPP-treated BMDCs promoted inflammatory cytokine production in splenic lymphocytes. In a mouse model of immunosuppression induced by cyclophosphamide, animals given CPP before and after an influenza vaccine challenge showed increased frequencies of dendritic cells and natural killer cells in the spleen, in addition to the recovery of vaccine-specific antibody titers. Moreover, innate myeloid cells in CPP-fed mice showed evidence of phenotypic modification via markedly enhanced interleukin(IL)-12 and interferon(IFN)-γ production in response to lipopolysaccharide(LPS) stimulation ex vivo. Our findings suggest that the administration of carrot pomace polysaccharides can significantly enhance the efficacy of influenza vaccination.

Rheumatoid arthritis (RA) is an autoimmune disease that starts with decreased tolerance to modified self-antigens and eventually leads to synovitis and destruction of bone and cartilage. Age is a risk factor for developing RA. Major changes in the immune system come with age due to chronic oxidative stress on the deoxyribonucleic acid (DNA) damage pathway, somatic mutation, modifications of auto-antigens, T cell tolerance and activation of fibroblast-like synoviocytes (FLS). Reactive oxygen species (ROS) generated by nicotinamide adenine dinucleotide phosphate oxidase 2 (NADPH oxidase 2) suppress T cell receptor signaling. Sirtuin 1 (SIRT1) is a critical immune suppressor of T cell activation and a key regulator of oxidative stress. When oxidative stress reduces activity of SIRT1, the breakdown of tolerance to modified self-antigens is expected. Generation of ROS can be perpetuated by enhanced DNA damage and dysfunctional mitochondria in a feedback loop during the development of RA. Through major T cell loss and selective proliferation of peripheral T cells, pro-inflammatory T cell pools with abnormal features are established in the T cell compartment. Hypoxic and inflammatory condition in synovium perpetuates ROS generation, which leads to the activation of FLS. In both T cell and synovium compartment, oxidative stress reshapes the immune system into the development of pre-clinical RA. (J Rheum Dis 2016;23:340-347)

Rheumatoid arthritis (RA) is a common autoimmune disease characterized by immune cell infiltration of the synovium, leading to the loss of cartilage, bone, and joint function. Although regulatory T (Treg) cells are thought to modulate the initiation and progression of RA, a consensus has yet to be reached regarding the function and composition of Treg cells in RA patients. To address these discrepancies, we analyzed not only the total Treg frequency but also that of Treg subpopulations in the peripheral blood of RA patients and healthy controls by flow cytometry. We found that the total Treg population was not significantly different between RA and control subjects. However, the effector Treg cell subgroup, defined as CD45RA−CD25hi, showed markedly decreased frequency in RA patients. In addition, the total Treg population from RA patients showed a significant decline in the expression of CD25. Both the naïve and effector Treg subgroups also showed marked reduction of CD25 expression in RA patients compared to controls. These data suggest that the decreased frequency of effector Treg cells and overall reduction of CD25 expression in Treg cells in the peripheral blood may be evidence of altered Treg homeostasis associated with RA pathogenesis.

Dendritic cells (DC) are specialized antigen-presenting cells that initiate and orchestrate the body’s immune response to bridge the innate and adaptive systems. Here we report developing a standardized evaluation system for immunity-boosting functional foodstuffs using bone marrow-derived dendritic cells. A DC-based evaluation system can indicate the type, magnitude, and specificity of immune responses elicited by an immune-boosting food item. We monitored the expression profile of DC maturation markers, including CD11b, CD11c, CD40, PD-L1/L2, CD80, CD86, and MHC, by flow cytometry to define immunity indexes. These indexes are then consolidated to a 4-point scale to describe the immunogenic and tolerogenic capabilities of the immunity-boosting food candidate. Among well-known immunoregulatory materials, red ginseng extracts, fucoidan, and polysaccharide-K were found to belong to the highest grade of immunogenicity, while extract of the Ostericum root was among the most tolerogenic foods. Extracts of Peucedanum japonicum Thunberg root and Psidium guajava L. leaves also showed high tolerogenic capabilities. Our results suggest that this assay is an effective method to characterize and screen the immune boosting effects of food and pharmaceutical materials in a standardized manner.