Optimization on preparation condition of epimedium polysaccharide liposome and evaluation of its adjuvant activity

The aim of this strategy was to investigate whether the adjuvant activity of epimedium polysaccharide (EPS) could be further enhanced after encapsulated with liposome. In preparation of EPS liposome (EPSL) test, an orthogonal L(9) (3(4)) test design was used to optimize the preparation condition of EPSL. In adjuvant activity test, 350 14-day-old chickens were randomly assigned to 7 groups and vaccinated with Newcastle disease (ND) vaccine. Simultaneously, the chickens in experimental groups were injected with EPSL at three doses, EPS and blank liposome, respectively. The activity of lymphocytes proliferation, titer of serum antibody and concentrations of cytokines were determined. Results showed that the optimal preparation condition of EPSL was that ratio of drug to lipid, ratio of soybean phospholipid to cholesterol, ultrasonic time, and water bath temperature were 1:30, 4:1, 10 min and 40°C, respectively. EPSL could significantly enhance the immune response of ND vaccine and promote cytokines secretion, and its high dose possessed the best efficacy. These findings indicated that liposome encapsulation could significantly improve the adjuvant activity of EPS.