Immunogenicity and safety of liposome-vaccine encapsulating hepatitis B surface antigen and phosphodiester CpG oligodeoxynucleotides

CpG oligodeoxynucleotides （CpG ODN） as adjuvant have been extensively studied in recent years. Phosphodiester CpG ODN （PO CpG ODN） can perfectly mimic bacterial DNA in enhancing immune response but are vulnerable to nucleases in vivo. This study aimed to evaluate the immunostimulatory potential arid safety of phosphodiester CpG ODN encapsulated in nonphospholipid liposomes. BALB/c mice were immunized intramuscularly with different formulations of liposomes, CpG ODN and hepatitis B surface antigen （HBsAg）. The results demonstrated that the encapsulated PO CpG ODN were protected against rapid degradation in vivo and retained their adjuvant activity. PO CpG ODN encapsulated with HBsAg in liposomes induced strong Th1-biased or Th1/Th2 mixed humoral immune response in mice with the magnitude similar to their phosphothioate equivalent in the same formulation. High IFN-gamma production induced by this formulation confirmed the generation of strong cellular immune response. Additionally, co-delivery of HBsAg arid PO CpG ODN improved the immune response over that obtained with separate delivery. Safety experiment showed that liposome-encapsulaed PO CpG ODN and HBsAg caused mild systemic and moderate local adverse reaction. In conclusion, our data shows that PO CpG ODN encapsulated in liposomes fully exhibit their Th1-type adjuvant activity arid act as a potential adjuvant for vaccines.

Effects of CpG-ODNs on phenotype and function of monocyte-derived dendritic cells in chronic hepatitis B

AIM:To study the effects of synthetic nonmethylated CpG-containing oligodeoxynucleotides(CpG-ODNs) ,either alone or combined with recombinant Hepatitis B surface antigen(HBsAg) polypeptide,on the phenotype,function,and intracellular signaling pathways of monocyte-derived dendritic cells(DCs) in patients with chronic hepatitis B(CHB) .METHODS:Peripheral blood monocytes isolated from CHB patients and healthy volunteers were induced to be dendritic cells by recombinant human granulocyte-monocyte colony stimulating factor and interleukin-4.The DCs were then treated with CpG-ODNs,CpGODNs/HBsAg,or tumor necrosis factor(TNF)-αfor 18 h.The expression of surface molecules including HLA-DR,CD86,and CD1a in DCs were detected by flow cytometry,and the expression of signal transducers and activators of transcription(STAT1,3,4,5,6) and suppressors of cell signaling(SOCS1,3) were determined by Western blotting assay.In addition,the capacity of DCs to stimulate allogeneic T lymphocytes and the amount of IL-12p70 released from DCs were measured.RESULTS:In the DCs derived from patients with CHB,treatment with TNF-α,CpG-ODNs,or CpG-ODNs/HBsAg,as compared to the vector control,significantly increased the expression of HLA-DR,stimulated the release of IL-12p70,and enhanced the capacity of DCs to stimulate allogenic T lymphocytes.The expressions of STAT1/4/6 and SOCS1/3,but not STAT3/5,were upregulated by TNF-α,CpG-ODNs,and CpG-ODNs/HBsAg.In addition,the expression of CD1a was upregulated only in the presence of both CpG-ODNs and HBsAg.CONCLUSION:The treatment with CpG-ODNs,either alone or combined with HBsAg,has a remarkable stimulatory effect on the impaired phenotype and function of DCs in CHB,possibly by regulating the expression of STAT1,4,6 and SOCS1,3.

LNP-CpG ODN-adjuvanted varicella-zoster virus glycoprotein E induced comparable levels of immunity with Shingrix^(TM) in VZV-primed mice

Latent varicella-zoster virus(VZV)may be reactivated to cause herpes zoster,which affects one in three people during their lifetime.The currently available subunit vaccine Shingrix^(TM) is superior to the attenuated vaccine Zostavax®in terms of both safety and efficacy,but the supply of its key adjuvant component QS21 is limited.With ionizable lipid nanoparticles(LNPs)that were recently approved by the FDA for COVID-19 mRNA vaccines as carriers,and oligodeoxynucleotides containing CpG motifs(CpG ODNs)approved by the FDA for a subunit hepatitis B vaccine as immunostimulators,we developed a LNP vaccine encapsulating VZV-glycoprotein E(gE)and CpG ODN,and compared its immunogenicity with Shingrix^(TM) in C57BL/6J mice.The results showed that the LNP vaccine induced comparable levels of gE-specific IgG antibodies to Shingrix^(TM) as determined by enzymelinked immunosorbent assay(ELISA).Most importantly,the LNP vaccine induced comparable levels of cellmediated immunity(CMI)that plays decisive roles in the efficacy of zoster vaccines to Shingrix^(TM) in a VZVprimed mouse model that was adopted for preclinical studies of Shingrix^(TM) .Number of IL-2 and IFN-γsecreting splenocytes and proportion of T helper 1(Th1)cytokine-expressing CD4^(+)T cells in LNP-CpG-adjuvanted VZV-gE vaccinated mice were similar to that of Shingrix^(TM) boosted mice.All of the components in this LNP vaccine can be artificially and economically synthesized in large quantities,indicating the potential of LNP-CpGadjuvanted VZV-gE as a more cost-effective zoster vaccine.

CpG ODN Enhances Immunization Effects of Hepatitis B Vaccine in Aged Mice

Oligodeoxynucleotides(ODN)containing unmethylated CpG dinucleotides in contexts of unique sequence (CpG motifs)is active as adjuvant in induction of cellular and humoral immune responses in young mice.To date,there are only limited reports about effect of CpG ODN on immune responses against hepatitis B(HB) infection in aged mice.Our studies demonstrated there were significant increases in secreting of total anti-HB IgG,IgG1 and IgG2a,as well as of IL-12 and IFN-γ,when CpG ODNs were injected together with hepatitis B antigen in aged mice.Moreover,CpG ODN could stimulate proliferation of spleen lymphocytes in a dose-dependent manner.Taken together,the results we obtained indicate that the adding of CpG ODN into the vaccine antigen might be useful in development of more effective vaccination for inducing anti-HB virus responses in the elderly.Cellular & Molecular Immunology.2004;1(2):148-152.