Biodegradable nanoparticle delivery of a Th2-biased peptide for induction of Th1 immune responses

The type of immune response developed against the hepatitis B virus (HBV) is crucial in determining the outcome of the disease. The protective effects of vaccine-induced antibody responses against subsequent exposure to HBV are well-established. After the establishment of chronic HBV infection, cell-mediated immune response is curative while humoral response is detrimental. A therapeutic vaccine that could switch the type of response could lead to disease resolution. Hepatitis B core antigen (HBcAg)(129-140) has been identified as a Th2-biased peptide in H-2(b) mice when it is administered along with complete Freund's adjuvant (CFA). We formulated HBcAg(129-140) along with monophosphoryl lipid A in poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles. Naive mice immunized with the nanoparticle formulation developed a strong Th1-type response while mice immunized with the control formulation of CFA and peptide did not. We then primed mice with CFA and peptide to establish a Th2-type immune response before administering the nanoparticle formulation. Mice receiving the nanoparticle formulation being primed with CFA still developed a strong Th1-type response, while mice that received incomplete Freund's adjuvant and peptide instead of nanoparticles did not. The ability of PLGA nanoparticles to alter the type of immune response elicited by a peptide, even in the context of an ongoing immune response, makes PLGA nanoparticles a strong candidate for the formulation of therapeutic vaccines.     

Antibody persistence and immune memory 4 years post-vaccination with combined hepatitis A and B vaccine in adults aged over 40 years

Persistence of immune response was assessed in adults aged >40 years (N = 596) following primary vaccination with combined hepatitis A/B vaccine or concomitant monovalent hepatitis A and B vaccines. Anti-hepatitis A virus antibody responses persisted for at least 4 years regardless of the vaccine used, with anti-hepatitis B surface antibody responses higher and more sustained in subjects who received the combined hepatitis A/B vaccine. Response rates to an additional dose of the same vaccine(s) used for priming were high.     

Modulation of immune response induced by co-administration of DNA vaccine encoding HBV surface antigen and HCV envelope antigen in BALB/c mice

Plasmid DNA vaccines encoding the hepatitis B virus (HBV) surface and hepatitis C virus (HCV) envelope antigens, respectively, were constructed, and attempt were made to find the possibility of a divalent vaccine against HBV and HCV. The expression of each plasmid in Cos-1 cells was confirmed using immunocytochemistry. To measure the induced immune response by these plasmids in vivo, female BALB/c mice were immunized intramuscularly with 100 microg of either both or just one of the plasmids. Anti-HBV and HCV-specific antibodies and related cytokines were evaluated to investigate the generation of both humoral and cellular immune responses. As a result, specific anti-HBV and anti-HCV serum antibodies from mice immunized with these plasmids were observed using immunoblot. The levels of IL-2 and RANTES showing a Th1 immune response were significantly increased, but there was no change in the level of IL-4 (Th2 immune response) in any of the immunized groups. Compared with each plasmid DNA vaccine, the combined vaccine elicited similar immune responses in both humoral and cell-mediated immunities. These results suggest that the combined DNA vaccine can induce not only comparable immunity experimentally without antigenic interference, but also humoral and Th1 dominant cellular immune responses. Therefore, they could serve as candidates for a simultaneous bivalent vaccine against HBV and HCV infections.     

Strong and multi-antigen specific immunity by hepatitis B core antigen (HBcAg)-based vaccines in a murine model of chronic hepatitis B: HBcAg is a candidate for a therapeutic vaccine against hepatitis B virus

Experimental evidence suggests that hepatitis B core antigen (HBcAg)-specific cytotoxic T lymphocytes (CTL) are essential for the control of hepatitis B virus (HBV) replication and prevention of liver damage in patients with chronic hepatitis B (CHB). However, most immune therapeutic approaches in CHB patients have been accomplished with hepatitis B surface antigen (HBsAg)-based prophylactic vaccines with unsatisfactory clinical outcomes. In this study, we prepared HBsAg-pulsed dendritic cells (DC) and HBcAg-pulsed DC by culturing spleen DC from HBV transgenic mice (HBV TM) and evaluated the immunomodulatory capabilities of these antigens, which may serve as a better therapy for CHB. The kinetics of HBsAg, antibody levels against HBsAg (anti-HBs), proliferation of HBsAg- and HBcAg-specific lymphocytes, production of antigen-specific CTL, and activation of endogenous DC were compared between HBV TM vaccinated with either HBsAg- or HBcAg-pulsed DC. Vaccination with HBsAg-pulsed DC induced HBsAg-specific immunity, but failed to induce HBcAg-specific immunity in HBV TM. However, immunization of HBV TM with HBcAg-pulsed DC resulted in: (1) HBsAg negativity, (2) production of anti-HBs, and (3) development of HBsAg- and HBcAg-specific T cells and CTL in the spleen and the liver. Additionally, significantly higher levels of activated endogenous DC were detected in HBV TM immunized with HBcAg-pulsed DC compared to HBsAg-pulsed DC (p<0.05). The capacity of HBcAg to modulate both HBsAg- and HBcAg-specific immunity in HBV TM, and activation of endogenous DC in HBV TM without inducing liver damage suggests that HBcAg should be an integral component of the therapeutic vaccine against CHB.     

DNA vaccines for prophylactic or therapeutic immunization against hepatitis B virus

DNA vaccines, with which the antigen is synthesized in vivo after direct introduction of its encoding sequences, offer a unique method of immunization that may overcome many of the deficits of traditional antigen-based vaccines. By virtue of the sustained in vivo antigen synthesis and the comprised stimulatory CpG motifs, plasmid DNA vaccines appear to induce strong and long-lasting humoral (anti-bodies) and cell-mediated (T-help, other cytokine functions and cytotoxic T-cells) immune responses. In animal models, DNA vaccines against hepatitis B virus (HBV) give humoral and cell-mediated immunity superior to that of the current traditional antigen-based vaccines, indicating the possibility of a more effective prophylactic vaccine against HBV. Furthermore, DNA vaccines can overcome tolerance to and expression of HBV proteins in a transgenic mouse model of the HBV chronic carrier, opening up the possibility of an effective therapeutic DNA vaccine to treat chronic carriers of HBV.     

Posintro™-HBsAg, a modified ISCOM including HBsAg, induces strong cellular and humoral responses

To improve the hepatitis B vaccines on the market new adjuvant systems have to substitute aluminium. In this study the hepatitis B surface antigen (HBsAg) was incorporated into a novel adjuvant system, the Posintro?, a modification of the traditional immune stimulatory complexes (ISCOMs). This new HBsAg vaccine formulation, Posintro?-HBsAg, was compared to two commercial hepatitis B vaccines including aluminium or monophosphoryl lipid A (MPL) and the two adjuvant systems MF59 and QS21 in their efficiency to prime both cellular and humoral immune responses. The Posintro?-HBsAg induced the strongest humoral response with high titers of HBsAg specific antibody, high number of antigen specific B-cells and a strong T helper 1 (Th1) antibody profile when compared to the other adjuvant formulations. The Posintro?-HBsAg was also a strong inducer of cellular immune responses with induction of delayed type hypersensitivity (DTH) reaction and CD4(+) T-cell proliferation. In addition, Posintro?-HBsAg was the only vaccine tested that also induced a strong cytotoxic T lymphocyte (CTL) response, with high levels of antigen specific CD8 T-cells secreting IFN-gamma mediating cytolytic activity. The results demonstrate that this novel experimental vaccine formulation, the Posintro?-HBsAg, is strongly immunogenic and can induce both class I and class II responses in experimental animals. This shows promise both for the protection against hepatitis B virus infection and as a potential therapeutic vaccine.     

Astragalus polysaccharides enhance immune responses of HBV DNA vaccination via promoting the dendritic cell maturation and suppressing Treg frequency in mice

Astragalus polysaccharides (APS), an extract from a kind of Chinese traditional herb Astragalus membranaceus, was proved to have strong immunoregulatory properties. In this study, APS was employed as an adjuvant of Hepatitis B virus (HBV) DNA vaccine (pcDS2) and its' effects on immune system of mice were investigated. Our data demonstrated that APS as an adjuvant could increase the HBsAg-specific antibody level as well as the proliferating activity of T cells. APS also could induce CD4⁺ T cells to produce IL-4, IL-2 and IFN-γ and enhance IFN-γ expression of CD8⁺ T cells. Moreover, APS could induce the robust activity of the cytotoxic lymphocytes (CTL). Additionally, APS could stimulate the dendritic cells (DC) maturation which is characterized by up-regulation of MHC I/II, CD40, CD80 and CD86, and decreased the frequency of the regulatory T cells (nTreg). Collectively, these findings suggest that APS is a potent adjuvant for the hepatitis B DNA vaccine and can enhance the immune responses of HBV DNA vaccine via promoting DC maturation and inhibit the Treg frequency.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

流感DNA疫苗免疫BALB/c小鼠克服母源性抗体干扰的研究

目的 为了克服母源性抗体对子代的免疫抑制作用,寻找避免母源性抗体干扰的流感疫苗免疫策略.方法 以小鼠为动物模型,接种流感灭活疫苗或DNA疫苗,并用致死量流感病毒感染.感染后检测小鼠的存活率、肺部病毒滴度、体内抗体滴度等指标,对疫苗的保护效果进行评价.结果 母代与子代免疫相同的疫苗,不论是灭活疫苗还是DNA疫苗,子代体内的母源性抗体都抑制了子代免疫后的自动免疫应答,表现为子鼠接种疫苗后不能抵御致死量流感病毒感染;母代免疫流感灭活疫苗,子代免疫神经氨酸酶DNA疫苗,子鼠能够克服母源性抗体干扰,抵御致死量流感病毒感染;母代和子代免疫不同的DNA疫苗,即母代免疫血凝素或神经氨酸酶DNA疫苗,子代免疫神经氨酸酶或血凝素DNA疫苗,也能达到克服母源性抗体干扰的目的 .结论 流感DNA疫苗免疫BALB/c小鼠能克服母源性抗体的干扰,这为临床新生儿抗母源性抗体干扰的研究提供了实验参考.     

DNA-based vaccination against hepatitis B virus using dissolving microneedle arrays adjuvanted by cationic liposomes and CpG ODN

DNA vaccines are simple to produce and can generate strong cellular and humoral immune response, making them attractive vaccine candidates. However, a major shortcoming of DNA vaccines is their poor immunogenicity when administered intramuscularly. Transcutaneous immunization (TCI) via microneedles is a promising alternative delivery route to enhance the vaccination efficacy. A novel dissolving microneedle array (DMA)-based TCI system loaded with cationic liposomes encapsulated with hepatitis B DNA vaccine and adjuvant CpG ODN was developed and characterized. The pGFP expression in mouse skin using DMA was imaged over time. In vivo immunity tests in mice were performed to observe the capability of DMA to induce immune response after delivery of DNA. The results showed that pGFP could be delivered into skin by DMA and expressed in skin. Further, the amount of expressed GFP was likely to peak at day 4. The immunity tests showed that the DMA-based DNA vaccination could induce effective immune response. CpG ODN significantly improved the immune response and achieved the shift of immune type from predominate Th2 type to a balance Th1/Th2 type. The cationic liposomes could further improve the immunogenicity of DNA vaccine. In conclusion, the novel DMA-based TCI system can effectively deliver hepatitis B DNA vaccine into skin, inducing effective immune response and change the immune type by adjuvant CpG ODN.     

Pulmonary immunization: deposition site is of minor relevance for influenza vaccination but deep lung deposition is crucial for hepatitis B vaccination

Vaccination via the pulmonary route could be an attractive alternative to parenteral administration. Research towards the best site of antigen deposition within the lungs to induce optimal immune responses has conflicting results which might be dependent on the type of vaccine and/or its physical state. Therefore, in this study, we explored whether deep lung deposition is crucial for two different vaccines, i.e., influenza and hepatitis B vaccine. In view of this, influenza subunit vaccine and hepatitis B surface antigen were labeled with a fluorescent dye and then spray-dried. Imaging data showed that after pulmonary administration to mice the powders were deposited in the trachea/central airways when a commercially available insufflator was used while deep lung deposition was achieved when an in-house built aerosol generator was used. Immunogenicity studies revealed that comparable immune responses were induced upon trachea/central airways or deep lung targeting of dry influenza vaccine formulations. However, for hepatitis B vaccine, no immune responses were induced by trachea/central airways deposition whereas they were considerable after deep lung deposition. Thus, we conclude that deep lung targeting is not a critical parameter for the efficacy of pulmonary administered influenza vaccine whereas for hepatitis B vaccine it is.     

治疗性乙型肝炎疫苗的研究进展与临床评价

目的:探讨治疗性乙型肝炎(HBV)疫苗的分类、机制及疗效。方法:检索、综述国内外有关的最新文献。结果:治疗乙型肝炎的疫苗是通过改造、构建等方法以提高抗原的免疫原性,刺激机体细胞免疫功能,消除免疫耐受,达到免疫清除的目的。目前研究的疫苗有蛋白质疫苗、核酸疫苗、树突状疫苗。结论:基因重组技术的发展与应用使利用疫苗来治疗HBV感染成为可能。