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ISSN
1672-9145
Acta Biochim Biophys Sin
2005, 37(3): 199–204
CN 31-1940/Q
Co-expression and Immunity of Legionella pneumophila mip Gene
and Immunoadjuvant ctxB Gene
Tao WANG, Jian-Ping CHEN*,
Hong LI, Ke-Qian ZHI1, Lei ZHANG, Chun-Lei YANG2, and
Da-Chang TAO2
School of Preclinical and Forensic Medicine of West China, Sichuan
University, Chengdu 610041, China;
1School of Stomatology, Xi’an Jiaotong University, Xi’an 710004,
China;
2School of Life Science, Sichuan University, Chengdu 610041, China
Abstract The mip gene of Legionella
pneumophila and the ctxB gene of Vibrio cholerae were
amplified by PCR respectively. The amplified cDNA was ligated to the
pcDNA3.1(+) vector. The recombinant plasmids pcDNA3.1-mip and pcDNA3.1-ctxB
were identified by restriction analysis and PCR, and further confirmed by
sequencing analysis. NIH3T3 cells were transfected with pcDNA3.1-mip and
pcDNA3.1-ctxB according to the Lipofection method. Transient and stable
products of the co-expression of the mip gene and ctxB gene were
detected by immunofluorescence and Western blotting. The results showed that
NIH3T3 cells were successfully transfected, and that the transiently and stably
co-expressed products can be detected in the transfected cells. To detect the
humoral and cellular immune response in immunized mice induced by the co-mmunization
of the mip and ctxB genes, female BALB/c mice were immunized
intramuscularly with pcDNA3.1-mip and pcDNA3.1-ctxB. The results showed that
the specific antibody titer and the cytotoxic T-lymphocyte response for
pcDNA3.1-mip immunization and co-immunization were increased compared with that
of pcDNA3.1(+) immunization. Furthermore, the specific antibody titer and
cytotoxic T-lymphocyte response for co-immunization were increased compared
with that of pcDNA3.1-mip immunization. Statistical analysis using one-way
analysis of variance (ANOVA) showed that there was a significant difference
between the groups (P<0.01). The results indicated that the ctxB
gene enhanced the humoral and cellular immune response to the mip gene
immunization. These findings provide experimental evidence to support the
development of the L. pneumophila DNA vaccine.
Key words Legionella
pneumophila; co-expression; humoral immunity; cellular immunity
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Received: November 23, 2004 Accepted: February 1,
2005
This work was supported by a grant from the National Natural Science
Foundation of China (No. 30300302)
*Corresponding author: Tel, 86-28-85501248; E-mail, [email protected]