Objective: To investigate the effect of low molecular weight heparin sodium adjuvant on the humoral immune response induced by hepatitis A virus vaccine in mice.
METHODS: ICR mice were randomly divided into 8 groups, 6 mice/group, which received hepatitis A live attenuated vaccine HepA-l (18 EU) and 5 different doses (100 μL, 20 μL, 10 μL, 1 μL, 0.1 μL) of low molecular weight heparin sodium mixed immunized mice were used as the experimental group, and normal saline was used as the negative control group (Blank), HepA-1 (18 EU) was used as the positive control group, and HepA-1 mixed with Al(OH)3 ( 300 μg) as the aluminum adjuvant control group, were immunized once, and the tail vein blood was collected at the 4th, 8th, 12th, and 16th weeks after immunization, and the level of anti-HAV antigen-specific IgG antibody in the serum of mice was detected by ELISA. During the experiment, the health status of the mice was observed, and after 16 weeks of immunization, the kidney, spleen, liver, lung, and heart of the mice in the maximum dose of low molecular weight heparin sodium group, 100 μL group and normal saline group, were used to prepare the main organs. Pathological sections were compared for observation.
RESULTS: Except for the negative control group, anti-HAV IgG was produced in all groups of mice after the 4th week of immunization, and the antibody level gradually increased with time, reached the highest value at the 8th week, and then gradually decreased. Antibody levels were different in different groups at the same time. Among them, in the 4th week and the 8th week, the aluminum adjuvant control group, the low molecular weight heparin sodium 100 μL group, the low molecular weight heparin sodium 20 μL group, and the low molecular weight heparin sodium 10 μL group had higher antibody levels than the positive control group, and the differences were as follows: Statistically significant (P < 0.05), at the 12th week, the levels of antibodies in the aluminum adjuvant control group, the low molecular weight heparin sodium 20 μL group and the low molecular weight heparin sodium 10 μL group were higher than those in the positive control group (P < 0.05). Weeks, the antibody levels in the aluminum adjuvant control group and the low molecular weight heparin sodium 10 μL group were higher than those in the positive control group (P < 0.05), but the antibody levels in the low molecular weight heparin sodium groups were lower than those in the aluminum adjuvant throughout the experimental period Antibody levels in the control group. It was shown that low molecular weight heparin sodium can enhance the HAV antigen-specific humoral immune response, and has an adjuvant effect. The optimal dose is 10 μL/group, but its adjuvant effect is lower than that of aluminum adjuvant. During the experiment, the mice in each group showed no abnormality. No lesions were observed in the kidney, spleen, liver, lung and heart tissue of mice in the low molecular weight heparin sodium 100 μL group.
Conclusion: Low molecular weight heparin sodium can significantly enhance the humoral immune response of mice induced by HAV antigen, and has the value of research and development as a new type of vaccine adjuvant.