Study On The Potentiating Effect Of Astragalan Polysaccharide In Immune Response Of Vaccine And Its Mechanism

A series of 5 experiments were conducted to investigate the extraction, physical and chemical characteristics, toxicity, security, immunomodulating effect of Astragalan polysaccharide(APS) and to approach the mechanism from view of cellular signal transduction.Experiment 1 Studies of the extraction, physical and chemical characteristics of Astragalan polysaccharideThis research was conducted to study the extraction, physical and chemical characteristics and content of Astragalan polysaccharide. The results showed that the percentage of extraction was 6.36%, the content of Astragalan polysaccharide was 81.3%, and cruse Astragalan polysaccharide did not contain protein and amylum. Experiment 2 Studies of the toxicity and security of Astragalan polysaccharideIn order to insure the using security of Astragalan polysaccharide, this research was conducted to study the toxicity and security of Astragalan polysaccharide.The results showed that Astragalan polysaccharide had non- toxicity, non-pyrogen and low-thrill characteristics, it can be used in many ways such as injection. Experiment 3 Effect of Astragalan polysaccharide on immune performance of broilersThis research was conducted to study the effect of Astragalan polysaccharide on immunity performance of young broilers. It was found that Astragalan polysaccharide had a effect on the immunity of broilers, the polysaccharide raised Newcastle antibody titer. The result indicated that Astragalan polysaccharide can stimulate the immunity of broilers, and increase the effect of vaccine. Experiment 4 Effect of Astragalan polysaccharide on splenocyte function of miceThis experiment was conducted to study the effects of Astragalan polysaccharide on splenocyte proliferation and cytokine secretion by using MTT method. It was found that Astragalan polysaccharide can promote splenocyte proliferation and IL-2 secretion in a dose dependent manner. The results indicated that Astragalan polysaccharide can promote selenocyte proliferation by stimulating the secretion of cytokine. Experiment 5 Effect of Astragalan polysaccharide on splenocyte signal transductionThis research was conducted to study the effect of Astragalan polysaccharide on splencyte signal transductions by determining the signal molecular NO, cAMP, cGMP. The result showed that Astragalan polysaccharide can increase splenocyte NO in a dose dependent manner, and had distinct effect at the concentration of 200 μg/mL. Astragalan polysaccharide also decreased cAMP concentration while it increased cGMP level. The above results indicated that Astragalan polysaccharide can modulate lymphocyte function by modulating signal transductions differently.