Eucommia ulmoides Leaf Polysaccharide in Conjugation with Ovalbumin Act as Delivery System Can Improve Immune Response

Abstract

In this investigation, to maximize the desired immunoenhancement effects of PsEUL and stimulate an efficient humoral and cellular immune response against an antigen, PsEUL and the model antigen ovalbumin (OVA) were coupled using the N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC) reaction to yield a novel delivery system (PsEUL-OVA). The physicochemical characteristics and immune regulation effects of this new system were investigated. We found the yield of this EDC method to be 46.25%. In vitro, PsEUL-OVA (200 μg mL−1) could enhance macrophage proliferation and increase their phagocytic efficiency. In vivo, PsEUL-OVA could significantly increase the levels of OVA-specific antibody (IgG, IgG1, IgG2a, and IgG2b) titers and cytokine (IL-2, IL-4, IL-6, IFN-γ) levels. Additionally, it could activate T lymphocytes and facilitate the maturation of dendritic cells (DCs). These findings collectively suggested that PsEUL-OVA induced humoral and cellular immune responses by promoting the phagocytic activity of macrophages and DCs. Taken together, these results revealed that PsEUL-OVA had the potential to improve immune responses and provide a promising theoretical basis for the design of a novel delivery system.

Enhancement of immune responses using ovalbumin‐conjugatedEucommia ulmoides leaf polysaccharides encapsulated in a cubic liquid‐crystalline phase delivery system

“…27,28 Conjugation of PsEUL with OVA PsEUL were conjugated to OVA using previously reported methods. 23 The purified PsEUL-OVA product was lyophilized to obtain powder and stored at 4 °C. The ratio of polysaccharide to protein in PsEUL-OVA was calculated by the BCA and phenol sulfate methods.…”

“…The lymphocyte subtype analysis assay was described in our previously study. 23 Briefly, three mice from each group were sacrificed on day 28 after the primary immunization. The spleens were removed, and single-cell suspensions (1 × 10 6 cells mL −1 ) were prepared.…”

“…20 Polysaccharides isolated from EU (PsEUL) have been widely demonstrated to have immune-enhancing properties due to their adjuvant effects. [21][22][23] Owing to the unavailability of EU bark, many studies have used EU leaves to examine the bioactive components of this plant. 24 Xu reported that water extracts obtained from EU leaves show anti-atherosclerotic and antioxidant effects, and can decrease diarrhea rates and promote growth in piglets.…”

“…25 In our previous study, PsEUL-OVA was demonstrated to show effective immune modulation effects. 23 However, the release rate and the antigen presentation efficiency of PsEUL-OVA need to be improved. In the present study, phytantriolan amphiphilic lipid materialwas added to an aqueous solution of F127 (dispersion system) to enable the spontaneous generation of cubic micelles.…”

“…EU has also been used to treat various pathological conditions, including lumbago, rheumatism and arthritis 20 . Polysaccharides isolated from EU (PsEUL) have been widely demonstrated to have immune‐enhancing properties due to their adjuvant effects 21‐23 . Owing to the unavailability of EU bark, many studies have used EU leaves to examine the bioactive components of this plant 24 .…”