DNA vaccination with genes encoding Toxoplasma gondii antigens ROP5 and GRA15 induces protective immunity against toxoplasmosis in Kunming mice.
OBJECTIVE
To evaluate the protective efficacy of a DNA vaccine encoding Toxoplasma gondii rhoptry protein 5 (ROP5) and GRA15 antigens.


METHODS
We constructed eukaryotic plasmids expressing pVAX-ROP5 and pVAX-GRA15, and measured the immune responses to these DNA vaccines.


RESULTS
Kunming mice immunized with pVAX-ROP5 or pVAX-GRA15 showed significantly increased serum IgG2a titers; Th1 responses association with the production of IFN-γ, IL-2, IL12 p40 and IL-12 p70; cell-mediated cytotoxic activity with increased frequencies of IFN-γ secreting CD8(+) T cells (CD8(+) IFN-γ+ T cells), as well as prolonged survival time (19.4 ± 4.9 days for ROP5; 17.8 ± 3.8 days for GRA15) and brain cyst reduction (57.4% for ROP5; 65.9% for GRA15) compared to control mice. Co-administration with pVAX-ROP5 and pVAX-GRA15 boosted the cellular and humoral immune responses, and significantly increased cyst reduction (79%) and prolonged the survival of immunized mice (22.7 ± 7.2 days).


CONCLUSIONS
Co-immunization of pVAX-ROP5 and pVAX-GRA15 increase the protective efficacy.
State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province 730046, PR China.
Jia
J
Chen
Zhong-Yuan
ZY
Li
Eskild
E
Petersen
Si-Yang
SY
Huang
Dong-Hui
DH
Zhou
Xing-Quan
XQ
Zhu
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D001921:Brain / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D051379:Mice; D016019:Survival Analysis; D014122:Toxoplasma / Q000235:genetics / Q000276:immunology*; D014123:Toxoplasmosis / Q000517:prevention & control*; D014611:Vaccination / Q000379:methods; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016207:Cytokines; D007074:Immunoglobulin G; D019444:Vaccines, DNA
DNA vaccine; GRA15; Kunming mice; ROP5; Toxoplasma gondii; protective immunity; toxoplasmosis