Enhanced immune response and protective efficacy of a<i>Treponema pallidum</i>Tp92 DNA vaccine vectored by chitosan nanoparticles and adjuvanted with IL-2

Zhao, Feijun; Wu, Yimou; Zhang, Xiao­hong; Yu, Jian; Gu, Wanyi; Liu, Shuangquan; Zeng, Tiebing; Zhang, Yuejun; Wang, Shiping

doi:10.4161/hv.7.10.16541

Cited by 28 publications

(29 citation statements)

References 16 publications

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“…Spleen cells were obtained from three rabbits from each group of infected rabbits (n=18, 15, 12, 9, 6 and 3) at corresponding times (weeks 8, 10, 12, 14, 30, and 34), as previously described [10]. Briefly, rabbits were euthanized by the air embolism method.…”

Section: Preparation Of Spleen Cell Suspensionsmentioning

confidence: 99%

“…As described in previous studies [10], rabbits were divided into seven groups, with 18 rabbits in each group. DNA vaccine groups: (i) pTpGpd (100 g), (ii) pTpGpd (100 g) coated with CS (30 g), (iii) pTpGpd (100 g) and pIL-2 (100 g), (iv) pIL-2 (100 g) and pTpGpd (100 g) coated with CS (30 g) were inoculated in the left hind leg quadriceps of rabbits.…”

Section: Immunization Protocolmentioning

confidence: 99%

“…To evaluate anti-Gpd humoral responses during infection, 1 mL of blood was collected from immunized rabbit ear veins for each group (n=18, 18, 18, 18, 18, 15, 12, 9, 9, 9, 9, and 6) at corresponding times (weeks 0, 2,4,6,8,10,12,14,20,24,28, and 32) after the first immunization, followed by centrifugation for isolation of serum. Each well was coated with 100 L purified recombinant Gpd protein (50 g mL 1 ) overnight at 4°C and incubated with 100 L of serial twofold dilutions of sera for 60 min at 37°C, before the addition of 100 L of horseradish peroxidase (HRP)-conjugated goat anti-rabbit IgG (1:2000) for 60 min at 37°C and 3,3′,5,5′-tetramethylbenzidine (TMB) substrate solution.…”

Section: Analysis Of Tpgpd-specific Antibody Responses By Elisa Durinmentioning

confidence: 99%

“…Escherichia coli JM109 and syphilis standard serum were obtained from the Pathogenic Biology Institute (Hengyang, China). The two DNA plasmids pTpGpd, encoding the TpGpd protein, and pIL-2, the IL-2 expression plasmid, were constructed and identified in our laboratory, as described previously [10,11]. HRP-labeled goat anti-human/rabbit IgG secondary antibody was purchased from Invitrogen (Shanghai, China).…”

Section: Bacteria Strains Dna Plasmids and Reagentsmentioning

confidence: 99%

“…Therefore, based on preliminary protection studies of New Zealand rabbits immunized with recombinant pcDNA3.1/Tp92 and pcDNA3.1/IL-2 (pIL-2) [10], the current study investigated the additional protective effects of using CS for vaccination. In this study, a Treponema pallidum (Tp) membrane protein Gpd expression plasmid, pcDNA3.1/TpGpd (pTpGpd), was coadministered with a cytokine adjuvant, pIL-2, and CS nanoparticles.…”

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confidence: 99%

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Assessment of the immune responses to Treponema pallidum Gpd DNA vaccine adjuvanted with IL-2 and chitosan nanoparticles before and after Treponema pallidum challenge in rabbits

Zhao

Zhang

Liu

et al. 2013

Sci. China Life Sci.

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Syphilis is a multistage, sexually transmitted disease caused by the spirochete, Treponema pallidum (Tp). A significantly high incidence of syphilis has been reported in several countries, including China, and there is an urgent need for the development of efficacious vaccines against syphilis. DNA vaccines are a major breakthrough in the field of vaccination with several advantages over traditional vaccines. Animal model studies of Tp DNA vaccines have not been reported elsewhere but our previous reports describe the development of a single-gene Tp DNA vaccine and preclinical immunization study. In this study, chitosan (CS) nanoparticles were used as a vector and an interleukin-2 expression plasmid (pIL-2) as an adjuvant to enhance a TpGpd DNA vaccine candidate (pTpGpd) in a rabbit Tp skin challenge model. At week 8 after the first immunization, three rabbits from each group were used to determine cytokine measurements and spleen lymphocyte proliferation assay. pTpGpd in combination with pIL-2 wrapped with CS led to the greatest enhancement of anti-TpGpd antibodies and T-cell proliferation. During infection, levels of anti-TpGpd antibodies and T-cell proliferation were measured. Both the serum special IgG and IL-2, interferon- were significantly increased by the co-injection of the IL-2 plasmid compared with the injection of TpGpd DNA alone (P<0.05). Furthermore, IL-2 plasmid coinjection efficiently enhanced the antigen-specific lymphocyte proliferation response. Additionally, the ratios of positive skin lesions and ulcer lesions in groups immunized with pTpGpd were significantly lower than those of the pIL-2, CS or pIL-2 mixed with CS control groups (P<0.001). CS vectored and pIL-2 adjuvanted pTpGpd immunized animals exhibited the lowest rates of positive skin tests (8.33%) and ulcer lesions (4.17%) and the fastest recovery (42 d). These experiments indicate that co-injection of a pIL-2 plasmid with pTpGpd DNA vaccine wrapped with CS can significantly strengthen the long-term stability of immune response during infection, efficiently improve the protective effect against T. pallidum spirochetes infection and attenuate syphilitic lesion development.Treponema pallidum (Tp), membrane protein, Gpd, CS, IL-2, nucleic acid vaccine Citation:Zhao F J, Zhang X H, Liu S Q, et al. Assessment of the immune responses to Treponema pallidum Gpd DNA vaccine adjuvanted with IL-2 and chitosan nanoparticles before and after Treponema pallidum challenge in rabbits.

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Section: Preparation Of Spleen Cell Suspensionsmentioning

confidence: 99%

Section: Immunization Protocolmentioning

confidence: 99%