Endogenous Danger Signal Low Molecular Weight Hyaluronan As New Vaccine Adjuvant

Infectious diseases such as HBV,HCV,HIV,and tumor that attack a large number of people all over the world,seriously endanger the human being's health. Vaccination is generally believed to be one of the most effective and cost-efficient ways to prevent or treat infectious disease and cancers.Vaccine includes preventive and therapeutic vaccine.Recently vaccines on researching focus on genetic engineering vaccine,subunit vaccine,synthetic peptide antigen vaccine;but the main problems of them are weak in immunogenicity and bad target,so the ideal adjuvant require to be added into vaccine antigen,especially therapeutic vaccine,and could enhance the humoral immune and CTL cellular immune so as to prevent or treat infectious diseases and cancers.Vaccine adjuvants are able to selectively stimulate immunity and improve immune effects.Most of vaccine adjuvants could only induce humoral immunity,but induce weak cellular immunity and even none.Therefore,it's urgent to develop new vaccine adjuvant in human,especially those effectively boost antigen immunogenicity and promote cellular immune response through cross presenting exoantigen.In order to better explicate the mechanism of immune recognition,Polly Matzinger has proposed a novel theory of danger signal model in 1994.It was assumed that immune systems take part in discriminating danger signals and non-danger signals.Danger signals released from injuried cells were able to activate antigen-presenting cells and trigger T/B cells effectively and then the relevant immunity was produced.It suggests that danger signals released from injured cells possessed potent adjuvant effects.Endogenous danger signals as adjuvant not only were able to significantly enhance humoral immunity,but also could enhance cellular immunity.So we firstly choose endogenous danger signals—low molecular weight hyaluronan,product of extracellular matrix degradation as new vaccine adjuvant,low molecular weight hyaluronan is refers to the molecular weight for＜10⁶ and then ICR mice were immunized with HAV antigen mixed with low molecular weight hyaluronan and HBV antigen coupled with low molecular weight hyaluronan, respectively;HAV antigen group,HBV antigen group and Al(OH)₃ adjuvant group are controls respectively.Anti-HAV IgG,anti-HBV IgG and CTL cellular immunity were examined by ELISA and LDH respectively,and get the results of anti-HAV IgG and anti-HBV IgG and CTL cellular immunity at different time.In addition,we choose 2.0 mg low molecular weight hyaluronan mixed with HBV antigen and aluminium adjuvant as control.7 days after immunization,we examined anti-HBV IgG antibody titer,specific anti-HBV IgG antibody is 1:30.84±1.43,but common aluminium adjuvant group is 1:9.46±3.99,the difference between them has statistical significance(P＜0.05).In the study,we initially get following results:endogenous danger signal low molecular weight hyaluronan significantly enhance anti-HAV IgG and anti-HBV IgG antibody titer and CTL cellular immunity.Fourthermore,our results testified that anti-HAV IgG and anti-HBV IgG of endogenous danger signals low molecular weight hyaluronan are significantly higher than aluminium group(P＜0.05) and anti-HBV IgG antibody titers are earlier than aluminium adjuant.In addition,we use the low molecular weight hyaluronan to prepare nanoparticles, and immunized ICR mice with the nanoparticles containing HBV antigen.And We initially explored the immune effect,found compared with non-nanoparticle experiment group and aluminium adjuvant,low molecular weight hyaluronan nanoparticles containing HBV antigen significantly enhance anti-HBV IgG antibody titer(P＜0.05).We also found in the safe experiment,ICR mice with common aluminium adjuvant appeared depilation.Bran's pathological result shows microglia nodule which suggests aluminium adjuvant may damage nervous system,but it was not observed abnormality at liver and kidney.But in the low molecular weight hyaluronan groups and low molecular weight hyaluronan nanoparticles containing HBsAg group, the toxic experiments and allergenic response are normal.Liver,kidney and brain's pathological results are also normal.These results demonatrated that low molecular weight hyaluronan is safe and non-toxicity and suitable for human. In conclusion,in this present study,we cleary shows that low molecular weight hyaluronan as new vaccine adjuvant not only could enhance special humoral immunity,but also significantly induce CTL cellular immunity;furthermore,low molecular weight hyaluronan nanoparticles could also induce strong immune effect.