Evaluation of immune responses in mice after DNA immunization with putative Toxoplasma gondii calcium-dependent protein kinase 5.
Toxoplasma gondii can cause serious public health problems and economic losses worldwide. Calcium-dependent protein kinases (CDPKs) are key mediators of T. gondii signaling pathways and are implicated as important virulence factors. In the present study, we cloned a novel T. gondii CDPK gene, named TgCDPK5, and constructed the eukaryotic expression vector pVAX-CDPK5. Then, we evaluated the immune protection induced by pVAX-CDPK5 in Kunming mice. After injection of pVAX-CDPK5 intramuscularly, immune responses, determined with lymphoproliferative assays and cytokine and antibody measurements, were monitored, and mouse survival times and brain cyst formation were evaluated following challenges with the T. gondii RH strain (genotype I) and the PRU strain (genotype II). pVAX-CDPK5 effectively induced immune responses with increased specific antibodies, a predominance of IgG2a production, and a strong lymphocyte proliferative response. The levels of gamma interferon (IFN-γ), interleukin 2 (IL-2), and IL-12(p70) and the percentages of CD3(+) CD4(+) and CD3(+) CD8(+) cells in mice vaccinated with pVAX-CDPK5 were significantly increased. However, IL-4 and IL-10 were not produced in the vaccinated mice. These results demonstrate that pVAX-CDPK5 can elicit strong humoral and cellular Th1 immune responses. The survival time of immunized mice challenged with the T. gondii RH strain (8.67 ± 4.34 days) was slightly, but not significantly, longer than that in the control groups within 7 days (P > 0.05). The numbers of brain cysts in the mice in the pVAX-CDPK5 group were reduced by ∼40% compared with those in the control groups (P < 0.05), which provides a foundation for the further development of effective subunit vaccines against T. gondii.
State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, People's Republic of China.
Nian-Zhang
NZ
Zhang
State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, People's Republic of China huangsiyang@caas.cn xingquanzhu1@hotmail.com.
Si-Yang
SY
Huang
State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, People's Republic of China College of Animal Science and Technology, Anhui Agricultural University, Hefei, Anhui Province, People's Republic of China.
Ying
Y
Xu
State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, People's Republic of China.
Jia
J
Chen
State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, People's Republic of China.
Jin-Lei
JL
Wang
College of Veterinary Medicine, Northeast Agricultural University, Harbin, Heilongjiang Province, China.
Wei-Peng
WP
Tian
State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu Province, People's Republic of China College of Animal Science and Veterinary Medicine, Heilongjiang Bayi Agricultural University, Daqing, Heilongjiang Province, People's Republic of China huangsiyang@caas.cn xingquanzhu1@hotmail.com.
Xing-Quan
XQ
Zhu
D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology; D001921:Brain / Q000469:parasitology; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D005260:Female; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics / Q000627:therapeutic use; D057809:HEK293 Cells; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D018664:Interleukin-12 / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D051379:Mice; D011494:Protein Kinases / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology*; D016052:Protozoan Vaccines / Q000276:immunology*; D014122:Toxoplasma / Q000235:genetics / Q000276:immunology; D014124:Toxoplasmosis, Animal / Q000276:immunology* / Q000401:mortality / Q000628:therapy; D014611:Vaccination; D022223:Vaccines, Subunit / Q000276:immunology* / Q000627:therapeutic use; D017871:Calcium-Calmodulin-Dependent Protein Kinases
D000913:Antibodies, Protozoan; D016207:Cytokines; D007074:Immunoglobulin G; D007371:Interferon-gamma; D016753:Interleukin-10; D018664:Interleukin-12; D007376:Interleukin-2; D015847:Interleukin-4; D011494:Protein Kinases; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D022223:Vaccines, Subunit; D017871:Calcium-Calmodulin-Dependent Protein Kinases