Search

The normal human microbiota, formerly called the "microbial flora," consists of bacteria, fungi, viruses, and parasites that colonise the skin and mucous membranes of the respiratory, gastrointestinal, and genitourinary tracts. The number and diversity of microorganisms varies between different body niches and is greatest in the intestinal tract. The microbiota contributes to the homeostasis of the human organism by preventing colonisation by pathogenic microorganisms, participating in digestive processes and metabolism, and regulating immune functions. Various environmental and genetic factors can lead to an imbalance in the human microbiota, called dysbiosis, which can affect human health. Dysbiosis is usually the result of decreased microbial diversity and a lower number of saprophytic microorganisms, followed by an overgrowth of opportunistic species. The most common diseases directly related to intestinal dysbiosis are antibiotic-associated diarrhoea and pseudomembranous colitis, both of which are associated with the excessive growth of harmful bacteria and Clostridioides difficile following broad-spectrum antibiotic therapy. Dysbiosis is associated with various health conditions or diseases such as acne, psoriasis, eczema, chronic obstructive pulmonary disease, inflammatory bowel disease, obesity, metabolic syndrome, type 2 diabetes, autoimmune diseases and allergies, neurological diseases such as Parkinson's disease, Alzheimer's disease, epilepsy and stroke, depression, anxiety, infertility, preterm birth, and malignancies.

Tertiary Lymphoid Structures (TLS) are organized aggregates of immune cells such as T cells, B cells, and Dendritic Cells (DCs), as well as fibroblasts, formed postnatally in response to signals from cytokines and chemokines. Central to the function of TLS are DCs, professional antigen-presenting cells (APCs) that coordinate the adaptive immune response, and which can be classified into different subsets, with specific functions, and markers. In this article, we review current data on the contribution of different DC subsets to TLS function in cancer and autoimmunity, two opposite sides of the immune response. Different DC subsets can be found in different tumor types, correlating with cancer prognosis. Moreover, DCs are also present in TLS found in autoimmune and inflammatory conditions, contributing to disease development. Broadly, the presence of DCs in TLS appears to be associated with favorable clinical outcomes in cancer while in autoimmune pathologies these cells are associated with unfavorable prognosis. Therefore, it is important to analyze the complex functions of DCs within TLS in order to enhance our fundamental understanding of immune regulation but also as a possible route to create innovative clinical interventions designed for the specific needs of patients with diverse pathological diseases. [ABSTRACT FROM AUTHOR]

Simple Summary: The use of medicinal traditional plants and plant-derived compounds in the treatment of inflammatory states, including rheumatoid arthritis, is gaining attention due to their anti-inflammatory and immunomodulatory properties and fewer side effects compared to conventional drugs. The current study aimed to evaluate the therapeutic effects of the Mediterranean plant Teucrium montanum L. on collagen-induced arthritis in rats, in an in vivo animal model of rheumatoid arthritis. The effect of the Teucrium montanum extract was evaluated by examining the cellular and molecular components of innate and adaptive immunity that have been shown to play an important role in the pathogenesis of both rheumatoid arthritis and collagen-induced arthritis. The Teucrium montanum extract alleviated the clinical manifestation and improved the histopathological findings of arthritis in CIA. The extract improved the anti-/pro-oxidative balance in serum, suppressed the production of pro-inflammatory cytokines in affected joints, and suppressed the T cell responses in secondary lymphoid organs and the production of autoantibodies. Our results suggest the anti-inflammatory/immunomodulatory properties of Teucrium montanum extract and represent a basis for the further exploration of the possible therapeutic use of the extract or its compound/s. The anti-inflammatory/immunomodulatory effects of Teucrium montanum L. (TM), a plant distributed in the Mediterranean region, have been insufficiently examined. The effects of the TM ethanol extract were tested in a rat collagen-induced arthritis (CIA) model of rheumatoid arthritis. LC-MS was used for the phytochemical analysis of the TM extract. Dark Agouti rats were immunized with bovine type II collagen (CII) in incomplete Freund's adjuvant for CIA, and treated with 100 or 200 mg/kg of TM extract daily via oral administration. Clinical and histopathological evaluations and a flow cytometric analysis of the phenotypic and functional characteristics of splenocytes and draining lymph node cells were performed. The cytokines in the paw tissue culture supernatants and anti-CII antibodies in serum were determined by ELISA. The TM extract, with the dominant components verbascoside and luteolin 7-O-rutinoside, reduced the arthritic score and ankle joint inflammation in CIA rats, promoted the antioxidant profile in serum, and lowered pro-inflammatory TNF-α, IL-6 and IL-1β production. It suppressed the activation status of CD11b+ cells by lowering CD86, MHCII and TLR-4 expression, and promoted the Th17/T regulatory cell (Tregs) balance towards Tregs. A lower frequency of B cells was accompanied by a lower level of anti-CII antibodies in treated rats. These findings imply the favorable effect of TM extract on the clinical presentation of CIA, suggesting its anti-inflammatory/immunomodulatory action and potential therapeutic effect. [ABSTRACT FROM AUTHOR]

Notwithstanding prevalence gaps in micronutrients supporting immune functions, the significance of their deficits/supplementation for the efficacy of vaccines is underinvestigated. Thus, the influence of supplementation combining vitamins C and D, zinc, selenium, manganese, and N-acetyl cysteine on immune correlates/surrogates of protection conferred by a quadrivalent influenza vaccine (QIV) in mice was investigated. The supplementation starting 5 days before the first of two QIV injections given 28 days apart increased the serum titres of total and neutralizing IgG against each of four influenza strains from QIV. Accordingly, the frequencies of germinal center B cells, follicular CD4+ T helper (Th) cells, and IL-21-producing Th cells increased in secondary lymphoid organs (SLOs). Additionally, the supplementation improved already increased IgG response to the second QIV injection by augmenting not only neutralizing antibody production, but also IgG2a response, which is important for virus clearance, through favoring Th1 differentiation as indicated by Th1 (IFN-γ)/Th2 (IL-4) signature cytokine level ratio upon QIV restimulation in SLO cell cultures. This most likely partly reflected antioxidant action of the supplement as indicated by splenic redox status analyses. Thus, the study provides a solid scientific background for further research aimed at repurposing the use of this safe and inexpensive micronutrient combination to improve response to the influenza vaccine. [ABSTRACT FROM AUTHOR]