Physical Interaction of T Cells with Dendritic Cells Is Not Required for the Immunomodulatory Effects of the Edible Mushroom Agaricus subrufescens

Immunomodulatory activity of extracts from five edible basidiomycetes mushrooms in Wistar albino rats

Mushrooms are nutritious foods that are widely cultivated all over the world. They are rich in a range of compounds linked to improving functions of the immune system including carotenoids, alkaloids, lectins, enzymes, folates, fats, organic acids, minerals, polysaccharides, phenolics, proteins, tocopherols, terpenoids, and volatile compounds. In this study we investigated, the immunomodulatory activity in rats of the aqueous extracts of five of the most common edible mushrooms belonging to Family Basidiomycota-white-rot fungi including, Lentinula edodes, Agaricus bisporus, Pleurotus ostreatus, Pleurotus columbinus, and Pleurotus sajor-caju. Male Wistar albino rats were assigned to thirteen groups and Immunosuppression was induced by oral administration of dexamethasone (0.1 mg/kg), followed by oral administration of the mushroom extracts at low (200 mg/kg) and high (400 mg/kg) doses. A positive control group received the immune stimulant Echinacea extract Immulant® at (30 mg/kg), while the negative control group received only saline. From each animal, in each group, blood samples were collected after 15 days for complete blood counts and for measurement of immunologic parameters, including lysozyme activity, nitric oxide (NO) production and serum cytokines including tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ) and interleukin 1 beta (IL-1β) levels. Results have shown that white blood cells (WBCs) and lymphocytic counts were significantly boosted by high doses of each of the five mushroom extracts (207-289% increase for WBC and 153-175% for lymphocytes) with a significant increase in lysozyme activity (110-136% increase), NO concentration (159-232% increase) and cytokines as compared to the negative control group. Histopathological examination of the rats' spleen and thymus tissues has shown marked lymphocytic proliferation that was more obvious at the higher doses. In conclusion, our results showed that the five edible mushroom extracts revealed significant immunostimulatory effects preclinically particularly, at the higher doses (400 mg/kg) which can be considered the effective dose.

Using metabolomics to discover the immunomodulator activity of food plants

Many edible plants exhibit immunomodulator activities that have beneficial effects on human health. These activities include the ability to activate, multiply, or suppress elements of the immune response. Some of these plants promote health by strengthening host defences against different diseases. In this article, we provide a comprehensive review of the constituents of several edible plants, their immunomodulatory activity, and mechanism of actions for Carica papaya, Coffea sp, Asparagus cochinchinensis, Dioscorea alata, beans, mushrooms, herbs, spices, and several vegetables. The studies reported here are pre-clinical (in vitro and in vivo) and clinical studies (limited in number). The bioactive compounds responsible for the immunomodulator activity of these plants were yet to be identified. This is because the plant is naturally a complex mixture, whilst the immune system is also an intricate system involving many cells and cytokines/chemokines. Metabolomics is a key tool for conducting global profiling of metabolites in a complex system. Therefore, it offers the ability to identify the presence of compounds in plant extracts associated with their immunomodulation effects. Likewise, metabolomics can also be used to detect any changes to metabolites in the cell as a response to treatment. Therefore, affected metabolic pathways that lead to the activation of certain immune responses can be determined from one single experiment. However, we found in this review that the use of a metabolomics approach is not yet fully developed for an immunomodulator study of food plants. This is important for the direction of future research in this field because unlike medicinal plants, food plants are consumed on a regular basis in small amounts with more obvious effects on the immune system. Information about possible bioactive compounds, their interactions (synergism, antagonism), and how the human body responds to them should be studied in a more holistic way.

Immunological Mechanism and Clinical Application of PAMP Adjuvants

BACKGROUND

The host innate immune system can recognize Pathogen-Associated Molecular Patterns (PAMPs) through Pattern Recognition Receptors (PRRs), thereby initiating innate immune responses and subsequent adaptive immune responses. PAMPs can be developed as a vaccine adjuvant for modulating and optimizing antigen-specific immune responses, especially in combating viral infections and tumor therapy. Although several PAMP adjuvants have been successfully developed they are still lacking in general, and many of them are in the preclinical exploration stage.

OBJECTIVE

This review summarizes the research progress and development direction of PAMP adjuvants, focusing on their immune mechanisms and clinical applications.

METHODS

PubMed, Scopus, and Google Scholar were screened for this information. We highlight the immune mechanisms and clinical applications of PAMP adjuvants.

RESULTS

Because of the differences in receptor positions, specific immune cells targets, and signaling pathways, the detailed molecular mechanism and pharmacokinetic properties of one agonist cannot be fully generalized to another agonist, and each PAMP should be studied separately. In addition, combination therapy and effective integration of different adjuvants can increase the additional efficacy of innate and adaptive immune responses.

CONCLUSION

The mechanisms by which PAMPs exert adjuvant functions are diverse. With continuous discovery in the future, constant adjustments should be made to build new understandings. At present, the goal of therapeutic vaccination is to induce T cells that can specifically recognize and eliminate tumor cells and establish long-term immune memory. Following immune checkpoint modulation therapy, cancer treatment vaccines may be an option worthy of clinical testing.

High-Dose Cyclophosphamide Administration Orchestrates Phenotypic and Functional Alterations of Immature Dendritic Cells and Regulates Th Cell Polarization

High-dose cyclophosphamide (CTX) inhibits the immune response. Dendritic cells (DCs) are professional antigen presenting cells (APCs) with a crucial role in initiating immune responses and sustaining immune tolerance. The relative contribution of DCs to immunosuppression induced by high-dose CTX is not well-documented. In this study, we employed the CTX-induced immunosuppressive rat model to examine alterations in DCs. We generated and cultured monocyte-derived immature DCs (imDCs) in vitro and explored their capacity of antigen uptake, T cell priming, cytokine production, and surface marker expression following high-dose CTX. Subsequently, we co-cultured CTX-treated imDCs with Th cells to determine Th cell polarization, and further explored the Toll-like receptor/Myeloid differentiation primary response 88/Mitogen-activated protein kinase (TLR/MyD88/MAPK) pathway. Our results show reduced cell number and surface maker alterations in splenic CD103⁺ DCs of CTX-treated immunosuppressed rats. In vitro, high-dose CTX weakened the antigen uptake capacity and enhanced the T cell priming capacity of imDCs, in addition to triggering imDC surface marker alterations. TLR, MyD88, and MAPK expression levels, involved in mediating Th cell polarization, were also significantly elevated. Our collective findings indicate that high-dose CTX administration potentiates phenotypic and functional alterations of imDC. Such changes may contribute to the regulation of Th polarization.

Crucial Role of Nucleic Acid Sensing via Endosomal Toll-Like Receptors for the Defense of Streptococcus pyogenes in vitro and in vivo

Streptococcus pyogenes is a major human pathogen causing a variety of diseases ranging from common pharyngitis to life-threatening soft tissue infections and sepsis. Microbial nucleic acids, especially bacterial RNA, have recently been recognized as a major group of pathogen-associated molecular patterns (PAMPs) involved in the detection of Streptococcus pyogenes via endosomal Toll-like receptors (TLRs) in vitro. However, the individual contribution and cooperation between TLRs as well as cell-type and strain specific differences in dependency on nucleic acid detection during S. pyogenes infection in vitro have not been clarified in detail. Moreover, the role of particularly bacterial RNA for the defense of S. pyogenes infection in vivo remains poorly defined. In this study, we report that in all investigated innate immune cells involved in the resolution of bacterial infections, including murine macrophages, dendritic cells and neutrophils, recognition of S. pyogenes strain ATCC12344 is almost completely dependent on nucleic acid sensing via endosomal TLRs at lower MOIs, whereas at higher MOIs, detection via TLR2 plays an additional, yet redundant role. We further demonstrate that different S. pyogenes strains display a considerable inter-strain variability with respect to their nucleic acid dependent recognition. Moreover, TLR13-dependent recognition of S. pyogenes RNA is largely non-redundant in bone marrow-derived macrophages (BMDMs), but less relevant in neutrophils and bone marrow-derived myeloid dendritic cells (BMDCs) for the induction of an innate immune response in vitro. In vivo, we show that a loss of nucleic acid sensing blunts early recognition of S. pyogenes, leading to a reduced local containment of the bacterial infection with subsequent pronounced systemic inflammation at later time points. Thus, our results argue for a crucial role of nucleic acid sensing via endosomal TLRs in defense of S. pyogenes infection both in vitro and in vivo.

Potential of Mushroom Compounds as Immunomodulators in Cancer Immunotherapy: A Review

Since time immemorial, plants and their compounds have been used in the treatment and management of various ailments. Currently, most of conventional drugs used for treatment of diseases are either directly or indirectly obtained from plant sources. The fungal group of plants is of significance, which not only provides food directly to man but also has been source of important drugs. For instance, commonly used antibiotics are derived from fungi. Fungi have also been utilized in the food industry, baking, and alcohol production. Apart from the economic importance of the microfungi, macrofungi have been utilized directly as food, which is usually got from their fruiting bodies, commonly known as mushrooms. Due to their richness in proteins, minerals, and other nutrients, mushrooms have also been associated with boosting the immune system. This makes mushrooms an important food source, especially for vegetarians and immunosuppressed individuals including the HIV/AIDS persons. In complementary and alternative medicines (CAMs), mushrooms are increasingly being accepted for treatment of various diseases. Mushrooms have been shown to have the ability to stimulate the immune system, modulate humoral and cellular immunity, and potentiate antimutagenic and antitumorigenic activity, as well as rejuvenating the immune system weakened by radiotherapy and chemotherapy in cancer treatment. This potential of mushrooms, therefore, qualifies them as candidates for immunomodulation and immunotherapy in cancer and other diseases' treatment. However, a critical review on mushroom's immune modulating potential in cancer has not been sufficiently addressed. This review puts forward insights into the immune activities of mushroom associated with anticancer activities.