Construction of periodic Brugia malayi cysteine protease inhibitor and glyceraldehydes-3-phosphate dehydrogenase eukaryotic recombinant plasmid and its immunogenicity / 中华传染病杂志

ABSTRACT

ObjectiveTo construct the eukaryotic expression plasmids containing cysteine protease inhibitor (CPI) and glyceraldehydes-3-phosphate dehydrogenase (GAPDH) gene from periodic Brugia malayi (Bm),and to observe its cellular immune response in mouse.Methods pcDNA3.1 (+)-BmCPI/BmGAPDH was constructed.The recombinant plasmids were screened and identified by digestion with restriction enzyme.BALB/c mice were injected intramuscularly with a dosage of 100 μg purified recombinant plasmid DNA with GpG oligodeoxynucleotide (CpG ODN) and two same doses were administrated at 2-week intervals.pcDNA3.1 (+) and phosphate buffered solution (PBS) were used as controls.The tissue of muscles at 4 weeks after the third injection was collected and the target gene was detected by reverse transcription-polymerase chain reaction (RTPCR).Two weeks after the third immunization,the stimulation index (SI) of spleen lymphocytes of immunized mice was measured by methylthiazolyldiphenyl-tetrazolium bromide (MTT) method and the serum levels of interleukin (IL)-4 and interferon (IFN)-γ were detected by enzyme-linked immunosorbent assay (ELISA).The data were analyzed by t test.ResultsBmCPI/BmGAPDH gene in the injected muscle of the immunized mice was detected by RT-PCR. At 6 weeks after immunization,the SIot spleen T lymphocytes in pcDNA3.1 (+)-BmCPI/CpG group and pcDNA3.1 (+)-BmCPI/BmGAPDH/CpG group were 1.466 ± 0.635 and 1.610 ± 0.112,respectively,which were both higher than PBS group and pcDNA3.1( +)-CpG group (1.004 ± 0.019 and 1.078 ± 0.129,respectively) (t=64.438,45.318,42.749 and 34.314,respectively; all P＜0.05).At 4 weeks after immunization,the serum levels of IL-4 and IFN-γ of mice in pcDNA3.1 ( + )-BmCPI/BmGAPDH/ CpG group were significantly higher than those in pcDNA3.1 (+)-CpG group (t=288.053 and 76.453,respectively; both P＜0.05),while the serum level of IFN-γ was also higher than that in pcDNA3.1 (+)-BmCPI/CpG group (t=129.642,P＜0.05). ConclusionThe recombinant eukaryotic plasmid pcDNA3.1 (+)-BmCPI/BmGAPDH could be expressed in mice,and could elicit specific cellular immune responses in immunized mice.