Plant-derived polysaccharides activate dendritic cell-based anti-cancer immunity

Abstract

Today, cancers pose a major public health burden. Although a myriad of cancer treatments are available, only a few have achieved clinical efficacy. This is partly attributed to cancers capability to evade host immunity by converting dendritic cells (DCs) from potent stimulators to negative modulators of immunity. Dendritic cell-based immunotherapy attempts to resolve this problem by manipulating the functional characteristics of DCs. Plant-derived polysaccharides (PDPs) can stimulate the maturation of DCs conferring on them the capacity to present internalised tumorigenic antigens to naïve T cells and subsequently priming T cells to eliminate tumours. PDPs have been used as immune modulators and later as anti-cancer agents by Traditional Chinese Medicine practitioners for centuries. They are abundant in nature and form a large group of heterogeneous though structurally related macromolecules that exhibit diverse immunological properties. They can induce antigen pulsed DCs to acquire functional characteristics in vitro which can subsequently be re-introduced into cancer patients. They can also be used as adjuvants in DC-based vaccines or independently for their intrinsic anti-tumour activities. Clinically, some in vitro generated DCs have been shown to be both safe and immunogenic although their clinical application is limited in part by unsatisfactory functional maturation as well as impaired migration to draining lymph nodes where T cells reside. We review the relative potencies of individual PDPs to induce both phenotypic and functional maturation in DCs, their relative abilities to activate anti-cancer immunity, the possible mechanisms by which they act and also the challenges surrounding their clinical application.

Advances in Research on Immunoregulation of Macrophages by Plant Polysaccharides

“…A large amount of experimental and clinical evidence indicates that long-term inflammation can increase the risk of cancer because a variety of inflammatory mediators can directly regulate the expression of oncogenes. In addition, key inflammation-related enzymes such as iNOS and COX-2 are associated with cancer induced by long-term inflammation (86, 87). Therefore, it is important to continue studying whether the pro- and anti-inflammatory factors induced by plant polysaccharides can maintain equilibrium in the body without causing harm due to excessive activation.…”

The immunostimulatory activity of polysaccharides fromGlycyrrhiza uralensis

“…Various plant-derived polysaccharides have been isolated and shown immunostimulatory activity (Kikete et al, 2018). Here, we found that GUPS promoted the maturation of DCs through TLR4 and its downstream p38, JNK and NF-κB signaling pathways, increased IL-12 production in vivo and enhanced the immunity of immunosuppressive mice.…”

“…It has been reported that polysaccharides can stimulate immune cells through different types of receptors including TLRs and scavenger receptors, which sequentially activate MAPK and NF-κB signaling pathways (Ferreira et al, 2015;Kikete et al, 2018). Our previous studies showed that Pleurotus ferulae polysaccharides and G. uralensis water extract promoted DCs maturation and cytokine production through TLR4 signaling pathway (Aipire et al, 2017;Li et al, 2017a;Li et al, 2017b).…”

“…Plant-derived polysaccharides have been drawn much attention due to their immunomodulatory activities and safety (Kikete et al, 2018;Li, Li & Zhang, 2015a). Accumulating evidence, including our own, has demonstrated that polysaccharides could enhance the immunity through activation of different targets, such as DCs and macrophages (Ferreira et al, 2015).…”

A fraction of Prunella vulgaris spike extract inhibited neutrophil elastase and protected mice against lipopolysaccharide-induced acute lung injury

“…Polysaccharides, which are macromolecules composed of long chains of monosaccharide units, are the key bioactive components of TCMs, and they possess immunomodulatory, antitumor, anti-in ammatory, hypoglycemic, anti-aging, and antioxidant effects [34][35][36][37]. In our previous study, the polysaccharide KSWP was isolated from Kochia scoparia fruit.…”