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A Toxoplasma gondii vaccine encoding multistage antigens in conjunction with ubiquitin confers protective immunity to BALB/c mice against parasite infection.

Yin H, Zhao L, Wang T, Zhou H, He S, Cong H - Parasit Vectors (2015)

Bottom Line: DNA vaccines have proved effective in the protection against parasites.Our results indicated that the DNA vaccine had the advantage of inducing a stronger humoral response, whereas the adenovirus-vectored vaccine effectively improved the cellular immune response.Priming vaccination with DNA vaccine and boosting with the recombinant adenovirus vaccine encoding ubiquitin conjugated multi-stage antigens of T. gondii was proved to be a potential strategy against the infection of type I and type II parasite.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Parasitology, Shandong University, School of Medicine, No. 44 Wenhuaxi Road, Jinan, Shandong, 250012, PR China. yinhuiquan521@126.com.

ABSTRACT

Background: Toxoplasma gondii is a widely prevalent intracellular parasite which infects almost all warm-blooded animals including humans and causes serious zoonotic toxoplasmosis. DNA vaccines have proved effective in the protection against parasites. However, the problems of weak immunity and inefficient delivery of DNA vaccine remain major issues. Therefore, comprehensive antigens derived from all stages of the parasite, effective adjuvants and delivery systems should be considered in the vaccine construction.

Methods: SAG3101-144,ROP18347-396, MIC6288-347, GRA7182-224, MAG158-125, BAG1156-211 and SPA142-200, derived from antigens in tachyzoite, bradyzoite and sporozoite stages of T. gondii were screened based on CD8(+) T cell epitope binding affinity to HLA and H-2. We constructed a recombinant DNA vaccine and an adenovirus vaccine encoding multi-stage antigen of T. gondii linked to ubiquitin molecules and vaccinated BALB/c mice with different strategies. Antibodies, cytokines, splenocytes proliferation, as well as the percentage of CD4(+) and CD8(+) T cells in immunized mouse were analyzed by the Enzyme-Linked Immunosorbent Assays (ELISA), Flow Cytometry (FCM). Protective efficacy was evaluated by challenging immunized mice with type I and type II parasite.

Results: Our results indicated that the DNA vaccine had the advantage of inducing a stronger humoral response, whereas the adenovirus-vectored vaccine effectively improved the cellular immune response. Priming with DNA vaccine and boosting with adenovirus-vectored vaccine induced Th1-type immune responses with highest levels of IgG2a and secretion of cytokines IL-2 and IFN-γ. Effective protection against type I and type II parasite with an increase in survival rate and a decrease in brain cyst burden was achieved in immunized mice.

Conclusions: Priming vaccination with DNA vaccine and boosting with the recombinant adenovirus vaccine encoding ubiquitin conjugated multi-stage antigens of T. gondii was proved to be a potential strategy against the infection of type I and type II parasite.

No MeSH data available.


Related in: MedlinePlus

The assay of subtype of T cells by FCM from immunized mice. Four weeks after the last immunization splenocytes from mice were collected and stained with anti-CD8a-PE monoclonal antibodies and anti-CD4-FITC antibodies. Percentage of positive stained cells were analyzed by FCM (a, b). *indicates statistically significant differences between the marked group
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Fig3: The assay of subtype of T cells by FCM from immunized mice. Four weeks after the last immunization splenocytes from mice were collected and stained with anti-CD8a-PE monoclonal antibodies and anti-CD4-FITC antibodies. Percentage of positive stained cells were analyzed by FCM (a, b). *indicates statistically significant differences between the marked group

Mentions: DNA vaccines encoding T. gondii multistage antigens with or without ubiquitin adjuvant immunized BALB/c mice twice via intramuscular injection at three-week intervals. The results show that not only specific sera antibodies but also splenocytes proliferation and the secretion of IFN-γ and IL-2 were stimulated in mice immunized with multistage DNA vaccine (p-MAS) (Fig. 2). A further 30 % increase in splenocytes proliferation and higher levels of IFN-γ (991 ± 10.14 pg/mL), IL-2 (360 ± 8.05 pg/mL) were observed in p-UMAS immunized mice than in p-MAS vaccinated mice. Moreover, the level of IgG, predominantly IgG2a, in the serum of p-UMAS vaccinated mice was significantly increased at day 35 and day 49 compared with p-MAS vaccinated mice (P <0.05). Furthermore, CD8+ T cell percentage were detected greater in the splenocytes of the p-UMAS vaccinated groups than in the p-MAS vaccinated group (P <0.05) (Fig. 3). These results indicate that ubiquitin conjugation can effectively improve the immunogenicity of the DNA vaccine and polarize the response towards the Th1-type immune response in mice.Fig. 2


A Toxoplasma gondii vaccine encoding multistage antigens in conjunction with ubiquitin confers protective immunity to BALB/c mice against parasite infection.

Yin H, Zhao L, Wang T, Zhou H, He S, Cong H - Parasit Vectors (2015)

The assay of subtype of T cells by FCM from immunized mice. Four weeks after the last immunization splenocytes from mice were collected and stained with anti-CD8a-PE monoclonal antibodies and anti-CD4-FITC antibodies. Percentage of positive stained cells were analyzed by FCM (a, b). *indicates statistically significant differences between the marked group
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4588682&req=5

Fig3: The assay of subtype of T cells by FCM from immunized mice. Four weeks after the last immunization splenocytes from mice were collected and stained with anti-CD8a-PE monoclonal antibodies and anti-CD4-FITC antibodies. Percentage of positive stained cells were analyzed by FCM (a, b). *indicates statistically significant differences between the marked group
Mentions: DNA vaccines encoding T. gondii multistage antigens with or without ubiquitin adjuvant immunized BALB/c mice twice via intramuscular injection at three-week intervals. The results show that not only specific sera antibodies but also splenocytes proliferation and the secretion of IFN-γ and IL-2 were stimulated in mice immunized with multistage DNA vaccine (p-MAS) (Fig. 2). A further 30 % increase in splenocytes proliferation and higher levels of IFN-γ (991 ± 10.14 pg/mL), IL-2 (360 ± 8.05 pg/mL) were observed in p-UMAS immunized mice than in p-MAS vaccinated mice. Moreover, the level of IgG, predominantly IgG2a, in the serum of p-UMAS vaccinated mice was significantly increased at day 35 and day 49 compared with p-MAS vaccinated mice (P <0.05). Furthermore, CD8+ T cell percentage were detected greater in the splenocytes of the p-UMAS vaccinated groups than in the p-MAS vaccinated group (P <0.05) (Fig. 3). These results indicate that ubiquitin conjugation can effectively improve the immunogenicity of the DNA vaccine and polarize the response towards the Th1-type immune response in mice.Fig. 2

Bottom Line: DNA vaccines have proved effective in the protection against parasites.Our results indicated that the DNA vaccine had the advantage of inducing a stronger humoral response, whereas the adenovirus-vectored vaccine effectively improved the cellular immune response.Priming vaccination with DNA vaccine and boosting with the recombinant adenovirus vaccine encoding ubiquitin conjugated multi-stage antigens of T. gondii was proved to be a potential strategy against the infection of type I and type II parasite.

View Article: PubMed Central - PubMed

Affiliation: Department of Human Parasitology, Shandong University, School of Medicine, No. 44 Wenhuaxi Road, Jinan, Shandong, 250012, PR China. yinhuiquan521@126.com.

ABSTRACT

Background: Toxoplasma gondii is a widely prevalent intracellular parasite which infects almost all warm-blooded animals including humans and causes serious zoonotic toxoplasmosis. DNA vaccines have proved effective in the protection against parasites. However, the problems of weak immunity and inefficient delivery of DNA vaccine remain major issues. Therefore, comprehensive antigens derived from all stages of the parasite, effective adjuvants and delivery systems should be considered in the vaccine construction.

Methods: SAG3101-144,ROP18347-396, MIC6288-347, GRA7182-224, MAG158-125, BAG1156-211 and SPA142-200, derived from antigens in tachyzoite, bradyzoite and sporozoite stages of T. gondii were screened based on CD8(+) T cell epitope binding affinity to HLA and H-2. We constructed a recombinant DNA vaccine and an adenovirus vaccine encoding multi-stage antigen of T. gondii linked to ubiquitin molecules and vaccinated BALB/c mice with different strategies. Antibodies, cytokines, splenocytes proliferation, as well as the percentage of CD4(+) and CD8(+) T cells in immunized mouse were analyzed by the Enzyme-Linked Immunosorbent Assays (ELISA), Flow Cytometry (FCM). Protective efficacy was evaluated by challenging immunized mice with type I and type II parasite.

Results: Our results indicated that the DNA vaccine had the advantage of inducing a stronger humoral response, whereas the adenovirus-vectored vaccine effectively improved the cellular immune response. Priming with DNA vaccine and boosting with adenovirus-vectored vaccine induced Th1-type immune responses with highest levels of IgG2a and secretion of cytokines IL-2 and IFN-γ. Effective protection against type I and type II parasite with an increase in survival rate and a decrease in brain cyst burden was achieved in immunized mice.

Conclusions: Priming vaccination with DNA vaccine and boosting with the recombinant adenovirus vaccine encoding ubiquitin conjugated multi-stage antigens of T. gondii was proved to be a potential strategy against the infection of type I and type II parasite.

No MeSH data available.


Related in: MedlinePlus