Adjuvant Effects of Platycodin D on Immune Responses to Infectious Bronchitis Vaccine in Chickens

Abstract

Adjuvants are common vaccine components. Novel adjuvants may improve the protective immunity conferred by vaccines against poultry diseases. Here, a lesshemolytic saponin, platycodin D (PD), isolated from the root of Platycodon grandiflorum was investigated as a potential alternative adjuvant. PD was tested as an adjuvant in the infectious bronchitis (IB) vaccine, because the existing IB vaccine has often failed to induce effective immune responses. The adjuvant activity of PD in conjunction with IB vaccine was evaluated in this study. Compared to control treatment, PD treatment significantly increased the proliferation of chicken peripheral blood mononuclear cells, concentration of interferon-γ in culture supernatants, and anti-IB antibody titer. In chickens pre-challenged with the Mass 41 infectious bronchitis virus (IBV), PD administration resulted in fewer and less severe clinical signs, lower mortality rate, and higher protection compared to control treatment. Histopathological examination showed that the lungs and kidneys of PD-treated chickens displayed fewer pathological lesions than those of control chickens. Our results also demonstrated that this new vaccine adjuvant improved chicken humoral and cellular immune responses without any side effects. Hence, our findings suggest that PD might serve as an effective adjuvant in IBV vaccines.

Effects of Drinking Water Supplementations with Nanoencapsulated Lime (Citrus aurantifolia) Leaf Extract on Broiler Chicken’s Blood Antioxidant Profiles and Meat Proximate Compositions

“…Results in current experiment (Table 2) indicated that the amount of CAT in the blood was escalated remarkably in group T5 (P<0.01), while GPx was drastically increased in group T4 (P<0.01) following nanocapsulated LLE supplementations. This finding was in line with the findings of Zhou et al [16] that reported supplementations of flavonoid baicalein, extracted from Scutellaria baicalensis's root, increased the profile of CAT and GPx in the blood serum of broiler chickens. Daramola [17] also noticed that supplementation of bitter leaf meal and Moringa oleifera leaf meal escalated the quantity of CAT and GPx in blood serum.…”

In vitro immune-enhancing effects of Platycodon grandiflorum combined with Salvia plebeian via MAPK and NF-κB signaling in RAW264.7 cells

“…Previous pharmacological studies on P. grandiflorum mainly examined its immune-enhancing effects in vitro and in vivo [15,18]. P. grandiflorum extracts primarily contained platycodin D and exhibited immuno-enhancing effects both in vitro and in vivo [16,17,38]. Treatment of RAW264.7 cells with the combination of fermented P. grandiflorum and soybean extract or…”

Potential Immunoregulatory Mechanism of Plant Saponins: A Review

“…Stimulating the proliferation of immune cells such as lymphocytes and monocytes [51][52][53][54][55][56][57][58];…”

“…and Th2 (IL-4, IL-6, GATA3, etc.) cytokines and transcription factors for a better balance of Th1/Th2 immune responses [52][53][54][55][56]58].…”

“…In addition, platycodin D (18) and platycodin D2 (19) can promote the secretion of cytokines by Th2 cells, namely, IL-4, IL-5, IL-10, and IL-13, thereby stimulating B lymphocyte proliferation and subsequent transformation into plasma cells, and promoting antigen-specific antibody production. IL-4 and IL-5 also cause eosinophils and mast cells to degranulate, making the parasite fragile and enhancing the body’s defense against parasitic infections [ 52 , 53 , 54 , 55 , 56 , 58 ]. Astragaloside IV (14) exhibits a specific activating influence on Th17 cells, which assume a pivotal role in the activation and recruitment of neutrophils to immune sites, and are capable of secreting IL-6, IL-17, and IL-22 to combat extracellular pathogens [ 92 , 95 ].…”