Reducing affinity as a strategy to boost immunomodulatory antibody agonism.

Antibody responses during infection and vaccination typically undergo affinity maturation to achieve high-affinity binding for efficient neutralization of pathogens1,2. Similarly, high affinity is routinely the goal for therapeutic antibody generation. However, in contrast to naturally occurring or direct-targeting therapeutic antibodies, immunomodulatory antibodies, which are designed to modulate receptor signalling, have not been widely examined for their affinity-function relationship. Here we examine three separate immunologically important receptors spanning two receptor superfamilies: CD40, 4-1BB and PD-1. We show that low rather than high affinity delivers greater activity through increased clustering. This approach delivered higher immune cell activation, in vivo T cell expansion and antitumour activity in the case of CD40. Moreover, an inert anti-4-1BB monoclonal antibody was transformed into an agonist. Low-affinity variants of the clinically important antagonistic anti-PD-1 monoclonal antibody nivolumab also mediated more potent signalling and affected T cell activation. These findings reveal a new paradigm for augmenting agonism across diverse receptor families and shed light on the mechanism of antibody-mediated receptor signalling. Such affinity engineering offers a rational, efficient and highly tuneable solution to deliver antibody-mediated receptor activity across a range of potencies suitable for translation to the treatment of human disease.

Heterophyllin B, a cyclopeptide from Pseudostellaria heterophylla, improves memory via immunomodulation and neurite regeneration in i.c.v.Aß-induced mice.

Pseudostellaria heterophylla, has historically been used as medicine food homology plant for thousand years in China. Our previous studies had indicated that daily intake of Pseudostellaria heterophylla extract enhanced cognitive memory. Herein, heterophyllin B (HET-B), a brain permeable cyclopeptide from Pseudostellaria heterophylla was determined, and the molecular mechanism underlying its memory improvement effects was investigated. Pseudostellaria heterophylla extract as well as HET-B reversed Aß25-35-induced axonal atrophy and neuronal apoptosis in cultured cortical neurons of mice. HET-B could enhance memory retrieval, modulate splenic T helper cell, and ameliorate neuroinflammation in i.c.v. Aß1-42 injected Alzheimer's disease (AD) mice. To explore the mechanism of action, network pharmacology was performed to predict protein targets and pathways of HET-B against AD. Five key targets were identified related to the effect of HET-B in AD intervention, and were clarified involved in axonal regeneration. We revealed for the first time that HET-B promoted memory retrieval through axonal regeneration and anti-neuroinflammation. This study provides a basis to research on HET-B as nutritional supplements for brain healthy.

Tetrahydroxylated bile acids improve cholestatic liver and bile duct injury in the Mdr2-/- mouse model of sclerosing cholangitis via immunomodulatory effects.

Bile salt export pump (Bsep) (Abcb11)-/- mice are protected from acquired cholestatic injury due to metabolic preconditioning with a hydrophilic bile acid (BA) pool with formation of tetrahydroxylated bile acids (THBAs). We aimed to explore whether loss of Bsep and subsequent elevation of THBA levels may have immunomodulatory effects, thus improving liver injury in the multidrug resistance protein 2 (Mdr2) (Abcb4)-/- mouse. Cholestatic liver injury in Mdr2-/- Bsep-/- double knockout (DKO), Mdr2-/- , Bsep-/- , and wild-type mice was studied for comparison. Mdr2-/- mice were treated with a THBA (3α,6α,7α,12α-Tetrahydroxycholanoic acid). RNA/protein expression of inflammatory/fibrotic markers were investigated. Serum BA-profiling was assessed by ultra-performance liquid chromatography tandem mass spectrometry. Hepatic immune cell profile was quantified by flow cytometric analysis (FACS). In vitro, the THBA effect on chenodeoxycholic acid (CDCA)-induced inflammatory signaling in hepatocyte and cholangiocytes as well as lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-induced macrophage activation was analyzed. In contrast to Mdr2-/- , DKO mice showed no features of sclerosing cholangitis. Sixty-seven percent of serum BAs in DKO mice were polyhydroxylated (mostly THBAs), whereas Mdr2-/- mice did not have these BAs. Compared with Mdr2-/- , DKO animals were protected from hepatic inflammation/fibrosis. THBA feeding in Mdr2-/- mice improved liver injury. FACS analysis in DKO and Mdr2-/- THBA-fed mice showed changes of the hepatic immune cell profile towards an anti-inflammatory pattern. Early growth response 1 (EGR1) protein expression was reduced in DKO and in Mdr2-/- THBA-fed mice compared with Mdr2-/- control mice. In vitro, THBA-reduced CDCA induced EGR1 protein and mRNA expression of inflammatory markers in hepatocytes and cholangiocytes. LPS/IFN-γ-induced macrophage activation was ameliorated by THBA. THBAs repress EGR1-related key pro-inflammatory pathways. Conclusion: THBA and their downstream targets may represent a potential treatment strategy for cholestatic liver diseases.

Peroxisome proliferator-activated receptor-gamma (PPARγ) and its immunomodulation function: current understanding and future therapeutic implications.

INTRODUCTION: Pain is a multidimensional experience involving the biological, psychological, and social dimensions of each individual. Particularly, the biological aspects of pain conditions are a response of the neuroimmunology system and the control of painful conditions is a worldwide challenge for researchers. Although years of investigation on pain experience and treatment exist, the high prevalence of chronic pain is still a fact. AREAS COVERED: Peroxisome proliferator-activated receptor-gamma (PPARγ) is a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily. It regulates several metabolic pathways, including lipid biosynthesis and glucose metabolism, when activated. However, PPARγ activation also has a critical immunomodulatory and neuroprotective effect. EXPERT OPINION: This review summarizes the evidence of synthetic or natural PPARγ ligands such as 15d-PGJ2, epoxyeicosatrienoic acids, thiazolidinediones, and specialized pro-resolving mediators, representing an interesting therapeutic tool for pain control.

Characterization of Alpinia officinarum Hance polysaccharide and its immune modulatory activity in mice.

This study aimed to characterize the structural features of a novel water-soluble polysaccharide (AOHP) extracted from Alpinia officinarum Hance and to verify its regulating effect on mouse immunity. Cellulose DEAE-52 and Sephadex G-100 columns were used to obtain purified AOHP. Techniques including NMR, methylation, monosaccharide composition, FT-IR, and molecular weight determination were applied to investigate the physicochemical properties and structural characterization of AOHP. Then, the influence of AOHP on mice was studied. After oral administration of AOHP, organ indexes, serum biochemistry indexes, and cytokines in the spleens of the mice were analysed. The results showed that AOHP was composed of T-α-D-Glcp, (1,4)-α-D-Glcp and (1,4,6)-α-D-Glcp with a number-average molecular weight of 26.0 kDa and a weight-average molecular weight of 52.8 kDa. Additionally, the innate immune statuses of the mice were improved by treatment with AOHP, while no obvious damage was identified. To conclude, the immunomodulatory activity and biological safety make AOHP a viable candidate as an ingredient for healthcare drugs.

Topical Melatonin Exerts Immunomodulatory Effect and Improves Dermatitis Severity in a Mouse Model of Atopic Dermatitis.

Oral melatonin supplement has been shown to improve dermatitis severity in children with AD, but the mechanism of the effect is unclear, and it is uncertain whether melatonin has a direct immunomodulatory effect on the dermatitis. Topical melatonin treatment was applied to DNCB-stimulated Balb/c mice, and gross and pathological skin findings, serum IgE, and cytokine levels in superficial lymph nodes were analyzed. Secretion of chemokines and cell proliferative response after melatonin treatment in human keratinocyte HaCaT cells were also studied. We found that in DNCB-stimulated Balb/c mice, topical melatonin treatment improved gross dermatitis severity, reduced epidermal hyperplasia and lymphocyte infiltration in the skin, and decreased IP-10, CCL27, IL-4, and IL-17 levels in superficial skin-draining lymph nodes. Melatonin also reduced cytokine-induced secretion of AD-related chemokines IP-10 and MCP-1 and decreased IL-4-induced cell proliferation in HaCaT cells. Melatonin seems to have an immunomodulatory effect on AD, with IP-10 as a possible target, and topical melatonin treatment is a potentially useful treatment for patients with AD.

Immunomodulatory Effects of Pure Cylindrospermopsin in Rats Orally Exposed for 28 Days.

Cylindrospermopsin (CYN) is a ubiquitous cyanotoxin showing increasing incidence worldwide. CYN has been classified as a cytotoxin and, among its toxic effects, its immunotoxicity is scarcely studied. This work investigates for the first time the influence of oral CYN exposure (18.75; 37.5 and 75 µg/kg b.w./day, for 28 days) on the mRNA expression of selected interleukin (IL) genes (IL-1ß, IL-2, IL-6, Tumor Necrosis Factor alpha (TNF-α), Interferon gamma (IFN-γ)) in the thymus and the spleen of male and female rats, by quantitative real-time polymerase chain reaction (RT-qPCR). Moreover, their serum levels were also measured by a multiplex-bead-based immunoassay, and a histopathological study was performed. CYN produced immunomodulation mainly in the thymus of rats exposed to 75 µg CYN/kg b.w./day in both sexes. However, in the spleen only IL-1ß and IL-2 (males), and TNF-α and IFN-γ (females) expression was modified after CYN exposure. Only female rats exposed to 18.75 µg CYN/kg b.w./day showed a significant decrease in TNF-α serum levels. There were no significant differences in the weight or histopathology in the organs studied. Further research is needed to obtain a deeper view of the molecular mechanisms involved in CYN immunotoxicity and its consequences on long-term exposures.

Immunomodulatory Activity of the Most Commonly Used Antihypertensive Drugs-Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers.

This review article is focused on antihypertensive drugs, namely angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB), and their immunomodulatory properties reported in hypertensive patients as well as in experimental settings involving studies on animal models and cell lines. The immune regulatory action of ACEI and ARB is mainly connected with the inhibition of proinflammatory cytokine secretion, diminished expression of adhesion molecules, and normalization of CRP concentration in the blood plasma. The topic has significant importance in future medical practice in the therapy of patients with comorbidities with underlying chronic inflammatory responses. Thus, this additional effect of immune regulatory action of ACEI and ARB may also benefit the treatment of patients with metabolic syndrome, allergies, or autoimmune disorders.

Progesterone Inhibits the Establishment of Activation-Associated Chromatin During TH1 Differentiation.

TH1-mediated diseases such as multiple sclerosis (MS) and rheumatoid arthritis (RA) improve during pregnancy, coinciding with increasing levels of the pregnancy hormone progesterone (P4), highlighting P4 as a potential mediator of this immunomodulation. Here, we performed detailed characterization of how P4 affects the chromatin and transcriptomic landscape during early human TH1 differentiation, utilizing both ATAC-seq and RNA-seq. Time series analysis of the earlier events (0.5-24 hrs) during TH1 differentiation revealed that P4 counteracted many of the changes induced during normal differentiation, mainly by downregulating key regulatory genes and their upstream transcription factors (TFs) involved in the initial T-cell activation. Members of the AP-1 complex such as FOSL1, FOSL2, JUN and JUNB were particularly affected, in both in promoters and in distal regulatory elements. Moreover, the changes induced by P4 were significantly enriched for disease-associated changes related to both MS and RA, revealing several shared upstream TFs, where again JUN was highlighted to be of central importance. Our findings support an immune regulatory role for P4 during pregnancy by impeding T-cell activation, a crucial checkpoint during pregnancy and in T-cell mediated diseases, and a central event prior to T-cell lineage commitment. Indeed, P4 is emerging as a likely candidate involved in disease modulation during pregnancy and further studies evaluating P4 as a potential treatment option are needed.

A Targeted Complement Inhibitor CRIg/FH Protects Against Experimental Autoimmune Myasthenia Gravis in Rats via Immune Modulation.

Antibody-induced complement activation may cause injury of the neuromuscular junction (NMJ) and is thus considered as a primary pathogenic factor in human myasthenia gravis (MG) and animal models of experimental autoimmune myasthenia gravis (EAMG). In this study, we tested whether CRIg/FH, a targeted complement inhibitor, could attenuate NMJ injury in rat MG models. We first demonstrated that CRIg/FH could inhibit complement-dependent cytotoxicity on human rhabdomyosarcoma TE671 cells induced by MG patient-derived IgG in vitro. Furthermore, we investigated the therapeutic effect of CRIg/FH in a passive and an active EAMG rodent model. In both models, administration of CRIg/FH could significantly reduce the complement-mediated end-plate damage and suppress the development of EAMG. In the active EAMG model, we also found that CRIg/FH treatment remarkably reduced the serum concentration of autoantibodies and of the cytokines including IFN-γ, IL-2, IL-6, and IL-17, and upregulated the percentage of Treg cells in the spleen, which was further verified in vitro. Therefore, our findings indicate that CRIg/FH may hold the potential for the treatment of MG via immune modulation.

Comparative study on the immunomodulatory function of extracellular vesicles from different dairy products.

Bovine milk-derived extracellular vesicles (EVs) have been proved to have positive effects on innate immunity and intestinal health. However, the effect of different processing treatments on the biological function of EVs in dairy products remains unclear. Thus, we explored the immunomodulatory function of EVs from different dairy products (pasteurized milk, UHT milk, freeze-dried powder and organic milk powder) by constructing the RAW264.7 cell model, the most commonly used in vitro model to study immune responses and screen for anti-inflammatory active substances. The results showed that EVs from different dairy products had similar bidirectional immunomodulatory effects to EVs from raw milk, which not only promoted the normal macrophage proliferation and increased NO and cytokine (IL-1ß, IL-6 and TNF-α) levels, but also inhibited the lipopolysaccharide (LPS)-induced TLR4/NF-κB pathway and inflammatory cytokines. In particular, EVs from different dairy products also could regulate the expression of immune-related miR-155, miR-223 and miR-181a, which were involved in the anti-infection response. Although the immunomodulatory effects of EVs in the pasteurized milk and freeze-dried powder groups were lower than that of the raw milk group, they were superior to the UHT milk group and significantly higher than the organic milk powder group. Therefore, we hypothesize that pasteurization and freeze-drying treatments might have less effect on the physiological activity of EVs, making the potential health benefits of the corresponding products superior to those of other dairy products.

Immunomodulatory Properties of Masticadienonic Acid and 3α-Hydroxy Masticadienoic Acid in Dendritic Cells.

Dendritic cells are antigen-presenting cells, which identify and process pathogens to subsequently activate specific T lymphocytes. To regulate the immune responses, DCs have to mature by the recognition of TLR ligands, TNFα or IFNγ. These ligands have been used as adjuvants to activate DCs in situ or in vitro, with toxic effects. It has been shown that some molecules affect the immune system, e.g., Masticadienonic acid (MDA) and 3α-hydroxy masticadienoic acid (3α-OH MDA) triterpenes naturally occurring in several medicinal plants, since they activate the nitric oxide synthase in macrophages and induce T lymphocyte proliferation. The DCs maturation induced by MDA or 3a-OH MDA was determined by incubating these cells with MDA or 3α-OH MDA, and their phenotype was afterwards analyzed. The results showed that only 3α-OH MDA was able to induce DCs maturation. When mice with melanoma were inoculated with DCs/3α-OH MDA, a decreased tumor growth rate was observed along with an extended cell death area within tumors compared to mice treated with DCs incubated with MDA. In conclusion, it is proposed that 3α-OH MDA may be an immunostimulant molecule. Conversely, it is proposed that MDA may be a molecule with anti-inflammatory properties.

Structure identification of a polysaccharide in mushroom Lingzhi spore and its immunomodulatory activity.

Ganoderma lucidum spore serves as a well-known immunomodulatory functional food in Asia. The polysaccharides in G. lucidum spore are responsible for the claimed immunomodulatory activity. However, the structural information of polysaccharides remains unclear. In this work, the leading water-soluble polysaccharide in G. lucidum spore (GLSP-I) with a molecular weight of 128.0 kDa was isolated and purified. The monosaccharide composition analysed by gas chromatography indicated that GLSP-I was a glucan. Three side chains, including Glc-(1 â†’ 3)-Glc-(1 â†’ 3)-Glc-(1 â†’ 6)-Glc, Glc-(1 â†’ 6)-Glc-(1 â†’ 6)-Glc-(1 â†’ 6)-Glc and Glc-(1 â†’ 3)-Glc-(1 â†’ 3)-Glc-(1 â†’ 3)-Glc-(1 â†’ 3)-Glc, were identified by UPLC-MS/MS. The structural characteristics were further identified by NMR spectra. The results indicated that the backbone of GLSP-I was (1 â†’ 3)-ß-D-glucan, with side chains linking at O-6. The proposed structure was drawn as below. The immunomodulatory activity assay indicated that GLSP-I could activate macrophages in a dose-dependent manner.

Inflammatory Burden and Immunomodulative Therapeutics of Cardiovascular Diseases.

Phenotyping cardiovascular illness and recognising heterogeneities within are pivotal in the contemporary era. Besides traditional risk factors, accumulated evidence suggested that a high inflammatory burden has emerged as a key characteristic modulating both the pathogenesis and progression of cardiovascular diseases, inclusive of atherosclerosis and myocardial infarction. To mechanistically elucidate the correlation, signalling pathways downstream to Toll-like receptors, nucleotide oligomerisation domain-like receptors, interleukins, tumour necrosis factor, and corresponding cytokines were raised as central mechanisms exerting the effect of inflammation. Other remarkable adjuvant factors include oxidative stress and secondary ferroptosis. These molecular discoveries have propelled pharmaceutical advancements. Statin was suggested to confer cardiovascular benefits not only by lowering cholesterol levels but also by attenuating inflammation. Colchicine was repurposed as an immunomodulator co-administered with coronary intervention. Novel interleukin-1ß and -6 antagonists exhibited promising cardiac benefits in the recent trials as well. Moreover, manipulation of gut microbiota and associated metabolites was addressed to antagonise inflammation-related cardiovascular pathophysiology. The gut-cardio-renal axis was therein established to explain the mutual interrelationship. As for future perspectives, artificial intelligence in conjunction with machine learning could better elucidate the sequencing of the microbiome and data mining. Comprehensively understanding the interplay between the gut microbiome and its cardiovascular impact will help identify future therapeutic targets, affording holistic care for patients with cardiovascular diseases.

Structural characterization, and in vitro immunostimulatory and antitumor activity of an acid polysaccharide from Spirulina platensis.

In this study, a novel heteropolysaccharide named SP90-1 with immunostimulatory and antitumor activity was purified and characterized from Spirulina platensis. SP90-1 has a molecular weight of 63.92 kDa and mainly consists of rhamnose (Rha), glucose (Glc), galactose (Gal) and glucuronic acid (GlcA), followed by the minor components Fuc and Xyl. The backbone of SP90-1 was determined to be →2)-α-d-Rhap-(1 â†’ 2,3)-α-d-Rhap-(1 â†’ 4)-ß-d-Glcp-(1 â†’ [3)-ß-d-Rhap-(1→]3, with branches at the O-3 of Rha, consisting of the side chains 4-Galp and 4-GlcpA. SP90-1 was found to significantly enhance phagocytic capacity, promote the secretion of nitric oxide (NO), interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α (TNF-α) in RAW264.7 cells, and remarkably inhibit the growth of A549 lung cancer cells. These findings demonstrate that SP90-1 could potentially be further explored for immunomodulatory biomedical applications.

Cobalt-doped Ti surface promotes immunomodulation.

Here, cobalt-doped plasma electrolytic oxidation (PEO) coatings with different cobalt contents were prepared on Ti implants. The cobalt ions in the PEO coating exhibited a slow and sustainable release and thus showed excellent biocompatibility and enhanced cell adhesion.In vitroenzyme-linked immunosorbent assay and real-time polymerase chain reaction assays demonstrated that the cobalt-loaded Ti showed immunomodulatory functions to macrophages and upregulated the expression of anti-inflammatory (M1 type) genes and downregulated expression levels of pro-inflammatory (M2 type) genes compared with that of pure Ti sample. High cobalt content induced increased macrophage polarization into the M2 type. Furthermore, the findings from thein vivoair pouch model suggested that cobalt-loaded Ti could mitigate inflammatory reactions. The present work provides a novel strategy to exploit the immunomodulatory functions of implant materials.

Panobinostat enhances olaparib efficacy by modifying expression of homologous recombination repair and immune transcripts in ovarian cancer.

Histone deacetylase inhibitors (HDACi) sensitize homologous recombination (HR)-proficient human ovarian cancer cells to PARP inhibitors (PARPi). To investigate mechanisms of anti-tumor effects of combined HDACi/PARPi treatment we performed transcriptome analysis in HR- proficient human ovarian cancer cells and tested drug effects in established immunocompetent mouse ovarian cancer models. Human SKOV-3 cells were treated with vehicle (Con), olaparib (Ola), panobinostat (Pano) or Pano+Ola and RNA-seq analysis performed. DESeq2 identified differentially expressed HR repair and immune transcripts. Luciferised syngeneic mouse ovarian cancer cells (ID8-luc) were treated with the HDACi panobinostat alone or combined with olaparib and effects on cell viability, apoptosis, DNA damage and HR efficiency determined. C57BL/6 mice with intraperitoneally injected ID8-luc cells were treated with panobinostat and/or olaparib followed by assessment of tumor burden, markers of cell proliferation, apoptosis and DNA damage, tumor-infiltrating T cells and macrophages, and other immune cell populations in ascites fluid. There was a significant reduction in expression of 20/37 HR pathway genes by Pano+Ola, with immune and inflammatory-related pathways also significantly enriched by the combination. In ID8 cells, Pano+Ola decreased cell viability, HR repair, and enhanced DNA damage. Pano+Ola also co-operatively reduced tumor burden and proliferation, increased tumor apoptosis and DNA damage, enhanced infiltration of CD8+ T cells into tumors, and decreased expression of M2-like macrophage markers. In conclusion, panobinostat in combination with olaparib targets ovarian tumors through both direct cytotoxic and indirect immune-modulating effects.

Grandiflorenic acid isolated from Sphagneticola trilobata against Trypanosoma cruzi: Toxicity, mechanisms of action and immunomodulation.

Grandiflorenic acid (GFA) is one of the main kaurane diterpenes found in different parts of Sphagneticola trilobata. It has several biological activities, especially antiprotozoal action. In turn, Chagas disease is a complex systemic disease caused by the protozoan Trypanosoma cruzi, and the drugs available to treat it involve significant side effects and impose an urgent need to search for therapeutic alternatives. In this context, our goal was to determine the effect of GFA on trypomastigote and intracellular amastigote forms. Our results showed that GFA treatment led to significantly less viability of trypomastigote forms, with morphological and ultrastructural changes in the parasites treated with IC50 of GFA (24.60 nM), and larger levels of reactive oxygen species (ROS), mitochondrial depolarization, lipid droplets accumulation, presence of autophagic vacuoles, phosphatidylserine exposure, and plasma membrane damage. In addition, the GFA treatment was able to reduce the percentage of infected cells and the number of amastigotes per macrophage (J774A.1) without showing cytotoxicity in mammalian cell lines (J774A.1, LLCMK2, THP-1, AMJ2-C11), in addition to increasing TNF-α and reducing IL-6 levels in infected macrophages. In conclusion, the GFA treatment exerted influence on trypomastigote forms through an apoptosis-like mechanism and by eliminating intracellular parasites via TNF-α/ROS pathway, without generating cellular cytotoxicity.

Polysaccharides derived from Chinese medicinal herbs: A promising choice of vaccine adjuvants.

Adjuvants have been used in vaccines for a long time to promote the body's immune response, reducing vaccine dosage and production costs. Although many vaccine adjuvants are developed, the use in human vaccines is limited because of either limited action or side effects. Therefore, the development of new vaccine adjuvants is required. Many studies have found that natural polysaccharides derived from Traditional Chinese medicine (TCM) possess good immune promoting effects and simultaneously improve humoral, cellular and mucosal immunity. Recently polysaccharide adjuvants have attracted much attention in vaccine preparation because of their intrinsic characteristics: immunomodulation, biocompatibility, biodegradability, low toxicity and safety. This review article systematically analysed the literature on polysaccharides possessing vaccine adjuvant activity from TCM plants, such as Astragalus polysaccharide (APS), Rehmannia glutinosa polysaccharide (RGP), Isatis indigotica root polysaccharides (IRPS), etc. and their derivatives. We believe that polysaccharide adjuvants can be used to prepare the vaccines for clinical use provided their mechanisms of action are studied in detail.