The New Vaccine Adjuvants Effect Research On Chondroitin Sulfate B And L-Citrulline

To investigate the effect of Chondroitin Sulfate B (CSB) and L-Citrulline on humoral immune response induced by hepatitis A virus (HAV) vaccine in mice. The CSB and L-Citrulline at different concentrations were mixed with 18 EU HepA-1, and injected s.c. to ICR mice in several sites, using 200 μl of physiological saline as negative control, 18 EU of HepA-1 as positive control, and 18 EU HepA-1+ 300 μg aluminium hydroxide as adjuvant control. The serum samples were collected at the 4th,8th,12th and 16th week after immunization. from which sera were separated and determined for HAV-specific IgG by ELISA assay. The heart, liver, spleen, lung and kidney tissues of mice in CSB 65μg, L-Citrulline 12mg and negative control groups were collected at the end of experiment for pathological examination.From this study, we get the following results. ①Anti-HAV IgGs were detected in the sera of mice in various groups. The antibody level of mice in CSB 65μg group was the highest in adjuvant groups. The antibody level was maintained at a high level and significantly higher than that in positive control group at week 12 and 16 (t=6.856,3.354; P< 0.05). The antibody level of mice in CSB 65μg group was comparable to aluminum adjuvant control group at week 4,8,12 and 16. We demonstrated that the optimal dosage of CSB was 65μg, so we test the safety of 65ug dosage CSB. No pathological changes occurred in various tissues, and no abnormalities were observed during the whole study. And no pathological changes were observed inkidney, spleen, liver, lung or heart of mice in CSB 65μg group. ②Anti-HAV IgGs were detected in the sera of mice in various groups. The antibody level of mice in L-Citrulline 12mg group was the highest in adjuvant groups. The antibody level was significantly higher than that in positive control group at the 8th and 12th week (t=4.811,4.072;P<0.05). The antibody level of mice in L-Citrulline 12mg group was comparable to aluminum adjuvant control group at week 8 and 12. But it decreased rapidly at the 20th week. We demonstrated that the optimal dosage of L-Citrulline was 12mg, so we test the safety of 12mg dosage L-Citrulline. No pathological changes occurred in various tissues, and no abnormalities were observed during the whole study. And no pathological changes were observed in kidney, spleen, liver, lung or heart of mice in L-Citrulline 12mg group. The experimental results suggest that both of the Chondroitin Sulfate B and L-Citrulline enhanced the humoral immune responses induced by HAV antigen in mice, which might be developed as novel adjuvants of vaccines.