Preparation of chitosan hydrochloride stabilized emulsion and its immunostimulatory effect / 生物工程学报

In order to increase the ability of oil-emulsion adjuvant to stimulate cellular immunity, chitosan hydrochloride with positive charge was selected to stabilize oil-in-water emulsion (CHE). In this paper, model antigen ovalbumin was selected to prepare vaccines with emulsion adjuvant, commercial adjuvant or no adjuvant. The emulsion was characterized by measuring the particle size, electric potential and antigen adsorption rate. BALB/c mice were immunized by intramuscular injection. Serum antibody levels, the numbers of IL-4-secreting cells in splenocytes, cytotoxic T lymphocyte (CTL) response, and the expression of central memory T cells were measured to evaluate the immunostimulatory effect. The results showed that chitosan hydrochloride can effectively stabilize the emulsion. The emulsion size is about 600 nm, and the antigen adsorption rate is more than 90%. After immunization, CHE could increase serum antibodies levels and increase IL-4 secretion. Expression of CTL surface activation molecules was also increased to stimulate CTL response further and to increase the CD44+CD62L+ in T cells proportion. CHE as adjuvant can stimulate humoral and cellular immunity more efficiently, and is expected to extend the duration of protection.

Structural characterization of PCP-Ⅰ from Poria as vaccine adjuvant and its hydrolytic oligosaccharide / 中国中药杂志

Poria is an important medical herb in clinic. The authors isolated a polysaccharide(PCP-Ⅰ) from Poria in previous studies, which is composed of galactose, mannose, fucose and glucose. PCP-Ⅰ exhibited significant adjuvant effects on H1N1 influenza vaccine, hepatitis B surface antigen and anthrax protective antigen, and its adjuvant activity was stronger than aluminium adjuvant. However, little is known about the chemical structure of PCP-Ⅰ at present. In this study, weak acid hydrolysis was used to obtain the backbone oligosaccharide of PCP-Ⅰ. Then periodate oxidation, Smith degradation, methylation analysis, Fourier transform infrared spectroscopy(FT-IR), nuclear magnetic resonance(NMR) and gas chromatography-mass spectrometry(GC-MS) were performed to investigate the chemical structural features of PCP-Ⅰ and its hydrolytic oligosaccharide(PCP-Ⅰ-hy-1). These results suggested that the backbone of PCP-Ⅰ was composed of galactose with α anomeric carbon and β anomeric carbon. The linking residues of galactan are(1→),(l→6) and(1→2,6).

1,8-cineol based influenza vaccine can improve vaccine efficacy on mice infected influenza virus / 中国免疫学杂志

Objective:To evaluate 1,8-cineol as vaccine adjuvants to enhance influenza vaccine immune efficacy.Methods:80 BALB/c mice were divided into blank control group,1,8-cineol group,HA group and HA+ 1,8-cineol group,each group of 20.Blank control group normal breeding,HA group accepted HA protein 0.2 μg,the HA+1,8-cineol group was given 0.2 μg HA+ 100 mg/kg 1,8-cineol,1,8-cineol group was given 100 mg/kg 1,8-cineol.Except the blank group,other groups of mice intranasal immunized for three times interval of one week.At the fourth weeks each mice was infected with 10LD50 influenza virus FM1.On the 6 days after the infected,10 mice in each group were collected serum,using enzyme-linked immunoassay(ELISA)to detect serum IgG,IgG1b,IgG2a, IgG2b in 450 nm absorbance values(OD).Removed the lung tissue and measured the lung index and pathological.Remaining mice continue to observe 15 days and record the deaths,calculating the infected mice survival rate.Results:Compared with the HA group, HA + 1,8-cineol group can reduce the lung index,alleviate the pulmonary lesions,improve the serum IgG,IgG1b,IgG2a,and increases the survival rate of infected mice.Conclusion:1,8-cineol as vaccine adjuvants,can strengthen the immune effect of influenza vaccine.

Bordetella bronchiseptica antigen enhances the production of Mycoplasma hyopneumoniae antigen-specific immunoglobulin G in mice

We previously demonstrated that Bordetella (B.) bronchiseptica antigen (Ag) showed high immunostimulatory effects on mouse bone marrow cells (BMs) while Mycoplasma (M.) hyopneumoniae Ag showed low effects. The focus of this study was to determine if B. bronchiseptica Ag can enhance the M. hyopneumoniae Ag-specific immune response and whether the host's immune system can recognize both Ags. MTT assay results revealed that each or both Ags did not significantly change BM metabolic activity. Flow cytometry analysis using carboxyfluorescein succinimidyl ester showed that B. bronchiseptica Ag can promote the division of BMs. In cytokine and nitric oxide (NO) assays, B. bronchiseptica Ag boosted production of tumor necrosis factor-alpha in M. hyopneumoniae Ag-treated BMs, and combined treatment with both Ags elevated the level of NO in BMs compared to that from treatment of M. hyopneumoniae Ag alone. Immunoglobulin (Ig)G enzyme-linked immunosorbent assay using the sera of Ag-injected mice clearly indicated that B. bronchiseptica Ag can increase the production of M. hyopneumoniae Ag-specific IgG. This study provided information valuable in the development of M. hyopneumoniae vaccines and showed that B. bronchiseptica Ag can be used both as a vaccine adjuvant and as a vaccine Ag.

Calcium phosphate nanoparticles as new generation vaccine adjuvants / 中华微生物学和免疫学杂志

Adjuvants have been used as critical components of vaccine.They were used to stabilize the antigens and potentiate the immune responses.Dose sparing is also of interests in recent years to be applied in potential pandemic situations or to lower the costs of vaccines.With the emerging nanotechnology in many aspects including the use in biomedical applications,the application of nanomaterials as vaccine adjuvants also attracted a lot of attentions in recent years.With favorable biological properties,such as well-defined and well-formed nanoparticles,biocompatibility,biodegradability and ability to induce humoral immunity and cellular immunity simultaneously,calcium phosphate nanoparticles (CaP) have the potentials to be developed as an immune potentiator to be used as vaccine adjuvants.Here,we reviewed the basic properties of CaP and their applications as vaccine adjuvants with antigens of different modalities such as inactivated virus,protein and naked DNAs.The mechanism of the adjuvanting effects is briefly described.Further the development of CaP as vaccine adjuvants with some designed surface modification could lead to next generation vaccine adjuvants with improved immune potentiating properties and safety profiles.

Evaluation of adjuvant effects of fucoidan for improving vaccine efficacy

Fucoidan is a sulfated polysaccharide derived from brown seaweed, including Fucus vesiculosus. This compound is known to have immunostimulatory effects on various types of immune cells including macrophages and dendritic cells. A recent study described the application of fucoidan as a vaccine adjuvant. Vaccination is regarded as the most efficient prophylactic method for preventing harmful or epidemic diseases. To increase vaccine efficacy, effective adjuvants are needed. In the present study, we determined whether fucoidan can function as an adjuvant using vaccine antigens. Flow cytometric analysis revealed that fucoidan increases the expression of the activation markers major histocompatibility complex class II, cluster of differentiation (CD)25, and CD69 in spleen cells. In combination with Bordetella bronchiseptica antigen, fucoidan increased the viability and tumor necrosis factor-alpha production of spleen cells. Furthermore, fucoidan increased the in vivo production of antigen-specific antibodies in mice inoculated with Mycoplasma hyopneumoniae antigen. Overall, this study has provided valuable information about the use of fucoidan as a vaccine adjuvant.

CpG-ODN plus alum as a composite adiuvant to enhance the immunogenicity of influenza split virion vaccine / 中华微生物学和免疫学杂志

Objective To evaluate the immuno-potentiating effects of CpG-ODN plus alum as a composite adjuvant on influenza split virion vaccine.Methods BALB/c mice were immunized with various amounts of 2009 H1N1 influenza split virion vaccine,alone or in combination with CpG-ODN,alum,or both (composite adjuvant).Antigen-specific humoral immune responses were evaluated by ELISA,hemagglutination inhibiting (HI) assay and neutralizing assay.Antigen-specific cellular immune responses were evaluated by ELISPOT assay,intracellular cytokine staining assay and in vivo CTL assay.Results Compared with the control group immunized with antigen alone,a single use of either adjuvant weakly enhanced the humoral immune responses,as indicated by the increase of antigen-specific IgG titers,HI titers and neutralizing titers by 3-6 folds,2-4 folds and 4-8 folds,respectively,after two immunizations.In contrast,the composite adjuvant induced more potent humoral immune responses; the antigen-specific IgG titers,HI titers and neutralizing titers were increased by 23-57 folds,9-20 folds and 16-64 folds,respectively.Consequently,the composite adjuvant achieved antigen-sparing by at least 16 folds.In addition,the composite adjuvant significantly enhanced the antigen-specific cellular immune responses,as revealed by the increase of IFN-γ-secreting CD4+ T cells and the enhancement of CTL activity in immunized mice.Conclusion CpG-ODN plus alum as a composite adjuvant can enhance the immunogenicity of influenza split virion vaccine and achieve the antigen-sparing effect.

Research Progress on PLGA Nanoparticles/Microspheres as DNA Carriers / 微生物学通报

Biodegradable PLGA [poly(lactide-co-glycolide acid)] have shown significant potential for sustained and targeted delivery of several pharmaceutical agents, including DNA. We reviewed the formulating approaches of PLGA nanoparticles/microspheres as DNA carriers and utilization for gene therapy and vaccine adjuvant.

Enhancement of Antigen-specific Antibody and CD8(+) T Cell Responses by Codelivery of IL-12-encapsulated Microspheres in Protein and Peptide Vaccination

BACKGROUND: Although IL-12 has been widely accepted to play a central role in the control of pathogen infection, the use of recombinant IL-12 (rIL-12) as a vaccine adjuvant has been known to be ineffective because of its rapid clearance in the body. METHODS: To investigate the effect of sustained release of IL-12 in vivo in the peptide and protein vaccination models, rIL-12 was encapsulated into poly (DL-lactic-co-glycolic acid) (PLGA). RESULTS: We found that codelivery of IL-12-encapsulated microspheres (IL-12EM) could dramatically increase not only antibody responses, but also antigen-specific CD4(+) and CD8(+) T cell responses. Enhanced immune responses were shown to be correlated with protective immunity against influenza and respiratory syncytial virus (RSV) virus challenge. Interestingly, the enhancement of CD8(+) T cell response was not detectable when CD4(+) T cell knockout mice were subjected to vaccination, indicating that the enhancement of the CD8(+) T cell response by IL-12EM is dependent on CD4(+) T cell "help". CONCLUSION: Thus, IL-12EM could be applied as an adjuvant of protein and peptide vaccines to enhance protective immunity against virus infection.