Protective immunity against acute toxoplasmosis in BALB/c mice induced by a DNA vaccine encoding Toxoplasma gondii elongation factor 1-alpha.
BACKGROUND
Toxoplasma gondii can infect almost all warm-blood animals including human beings. The high incidence and severe damage that can be caused by T. gondii infection clearly indicates the need for the development of a vaccine. T. gondii elongation factor 1-alpha (TgEF-1α) plays an important role in pathogenesis and host cell invasion for this parasite. The aim of this study was to evaluate the immune protective efficacy of a DNA vaccine encoding TgEF-1α gene against acute T. gondii infection in mice.


METHODS
A DNA vaccine (pVAX-EF-1α) encoding T. gondii EF-1a (TgEF-1α) gene was constructed and its immune response and protective efficacy against lethal challenge in BALB/c mice were evaluated.


RESULTS
Mice inoculated with the pVAX-EF-1α vaccine had a high level of specific anti-T. gondii antibodies and produced high levels of IFN-gamma, interleukin (IL)-4, and IL-17. The expression levels of MHC-I and MHC-II molecules as well as the percentages of both CD4(+) and CD8(+) T cells in mice vaccinated with pVAX-EF-1α were significantly increased (p < 0.05), compared with those in all the mice from control groups (blank control, PBS, and pVAXI). Immunization with pVAX-EF-1α significantly (p < 0.05) prolonged mouse survival time to 14.1 ± 1.7 days after challenge infection with the virulent T. gondii RH strain, compared with mice in the control groups which died within 8 days.


CONCLUSIONS
DNA vaccination with pVAX-EF-1α triggered strong humoral and cellular responses and induced effective protection in mice against acute T. gondii infection, indicating that TgEF-1α is a promising vaccine candidate against acute toxoplasmosis.
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. tongbaiws1003@163.com.
Shuai
S
Wang
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. 453425665@qq.com.
YuJian
Y
Wang
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. 2013107059@njau.edu.cn.
XiaoNi
X
Sun
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. zhangzhenchao525@163.com.
ZhenChao
Z
Zhang
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. 2012207035@njau.edu.cn.
TingQi
T
Liu
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. drgadahi@yahoo.com.
Javaid Ali
JA
Gadahi
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. barrhoum@gmail.com.
Ibrahim Adam
IA
Hassan
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. xulixin@njau.edu.cn.
LiXin
L
Xu
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. yanruofeng@njau.edu.cn.
RuoFeng
R
Yan
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. songxiaokai@njau.edu.cn.
XiaoKai
X
Song
College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, 210095, PR China. lixiangrui@njau.edu.cn.
XiangRui
X
Li
D056704:Adaptive Immunity; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D016207:Cytokines / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007111:Immunity, Cellular; D051379:Mice; D008807:Mice, Inbred BALB C; D020648:Peptide Elongation Factor 1 / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D015800:Protozoan Proteins / Q000145:classification / Q000235:genetics*; D016052:Protozoan Vaccines / Q000276:immunology*; D014122:Toxoplasma / Q000235:genetics*; D014123:Toxoplasmosis / Q000276:immunology / Q000517:prevention & control*; D019444:Vaccines, DNA / Q000276:immunology*
D000913:Antibodies, Protozoan; D016207:Cytokines; D020648:Peptide Elongation Factor 1; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D019444:Vaccines, DNA