[Enhancing protective immunity effects of TPI DNA vaccine against Schistosoma japonicum through codon optimization].
OBJECTIVE
To study the protective effect of codon optimized TPI DNA vaccine against Schistosoma japonicum infection.


METHODS
Sixty female BALB/c mice were randomly divided into 5 groups. The mice were injected through musculus quadriceps femoris with 100 microg pcDNA 3.1 control (Group A), pcDNA3.1-TPI (Group B), pcDNA 3.1-TPI-mHSP70 (Group C), pcDNA3.1-TPI.opt (Group D), and pcDNA3.1-TPI.opt-mHSP70 (Group E) respectively. All mice were immunized for three times with an interval of two weeks. The mice were challenged with (40+/-1) cercariae of S. japonicum per mouse by abdominal skin penetration 4 weeks after the last immunization, and sacrificed at 42 days post-challenge, the number of worms or hepatic eggs was counted. Blood was taken for the detection of IgG, IgG1, and IgG2a 2 days before immunization and before challenge, respectively. Spleen cells of 2 mice from each group were cultured and stimulated with ConA and rSjCTPI peptide, and the supernatant was collected for detection of IL-2, IL-4, IL-5, IFN-gamma, and TNF by flow cytometry.


RESULTS
ELISA showed that the mice in groups B, C, D, and E produced specific IgG and IgG1, IgG2a antibody isotypes, and the ratio of IgG2a/IgG1 was 1.73, 2.06, 2.44, and 3.09, respectively. The levels of IL-2, IFN-gamma and TNF in groups D and E were higher than that of groups B and C. The worm reduction rate and hepatic egg reduction rate in groups D (36.03%, 41.7%) and E (39.03%, 46.85%) were higher than those of groups B (26.28%, 28.35%) and C (28.38%, 31.39%) (P<0.01) .


CONCLUSIONS
The codon optimized TPI DNA vaccine induces higher level of protective effect and Th1-biased cellular immune response than those of non-optimized TPI DNA vaccine.
Jiangsu Institute of Parasitic Diseases, Key Laboratory on Technology for Parasitic Disease Prevention and Control, Ministry of Health, Jiangsu Provincial Key Laboratory on Molecular Biology of Parasites, Jiangsu Provincial Key Subject on Parasitic Diseases, Wuxi 214064, China.
Fei
F
Lu
Yin-Chang
YC
Zhu
Yang
Y
Dai
Xiao-Ting
XT
Wang
Jian-Xia
JX
Tang
Chun
C
Zhang
D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D001483:Base Sequence; D003062:Codon; D005260:Female; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000032:analysis; D007376:Interleukin-2 / Q000032:analysis; D015847:Interleukin-4 / Q000032:analysis; D015848:Interleukin-5 / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012549:Schistosoma japonicum / Q000201:enzymology / Q000235:genetics / Q000276:immunology*; D012554:Schistosomiasis japonica / Q000276:immunology / Q000517:prevention & control*; D014305:Triose-Phosphate Isomerase / Q000276:immunology*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*
D000909:Antibodies, Helminth; D003062:Codon; D007074:Immunoglobulin G; D007376:Interleukin-2; D015848:Interleukin-5; D014409:Tumor Necrosis Factor-alpha; D019444:Vaccines, DNA; D015847:Interleukin-4; D007371:Interferon-gamma; D014305:Triose-Phosphate Isomerase