ABSTRACT
In order to characterize the immunogenicity and immunoprotection of the Staphylococcus aureus (S. aureus) surface Isdb, we amplified Isdb gene from S. aureus Wood46 strain. The isdb gene was subsequently inserted into pET32a(+) vector and the recombinant plasmid was transformed into E. coli strain BL21. The recombinant Isdb was expressed and purified. Then, we immunized mice with the purified recombinant protein. The antibody level was measured by enzyme-linked immunosorbent assay. Finally, immunized mice were challenged with S. aureus strains Wood46 and HLJ23-1. These results showed that isdb gene sequences were highly conserved, and the recombinant Isdb was successfully expressed. The antibody titer in the immunized groups was increased significantly (P < 0.05) compared with the control, the protective rate of Isdb protein inducted by challenge with the two S. aureus stains Wood46 and HLJ23-1 was 62.5% and 75%, respectively. These results showed that the Isdb protein had high immunogenicity and immunoprotective capacity.
Subject(s)
Animals , Female , Male , Mice , Antibodies, Bacterial , Blood , Cation Transport Proteins , Genetics , Allergy and Immunology , Cloning, Molecular , Escherichia coli , Genetics , Metabolism , Genetic Vectors , Genetics , Immunization , Recombinant Proteins , Genetics , Allergy and Immunology , Staphylococcal Infections , Allergy and ImmunologyABSTRACT
To obtain and analyze the sequence of the nucleocapsid gene from bovine coronavirus, and to produce the fusion protein of the N gene in E.coli in order to use this recombinant protein for the study of bovine coronavirus. The N gene of BCV-DQ strain was amplified by RT-PCR, in which the primers were designed on the basis of N gene sequence of BCV-Mebus strain. The PCR products of 1 347 bp in length were cloned and sequenced, and then inserted into the prokaryotic vector pET30a. The recombinant plasmids were then transformed into Escherichia coli BL21 and identified by SDS-PAGE and Western blot assay. ELISA assay was optimized of N protein as the coating antigen to detect the viruses in the clinical samples. In comparison with 6 BCV strains in GenBank, the sequence identity was proved to be more than 98.3%. Result in SDS-PAGE showed that the fusion protein had a molecular weight of 60 ku, and could be specifically recognized by mouse serum against BCV. The indirect ELISA was used to test 256 serum samples collected from Heilongjiang province and 65.23% samples were positive. On testing field samples, an overall agreement of 95.31% was generated between the the neutralization test of viruses (VN) and indirect ELISA. It is apparent that the N gene was highly conservative and is expressed in E. coli in high level,also the prokaryotic expression products of this gene show a fine reactiongenicity in immune responses. It was also suggested that the N protein may be a useful antigen for sero-diagnosis and epidemiological investigation of BCV.
ABSTRACT
In order to characterize the Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity, immunogenicity and immunoprotection of the Staphylococcus aureus (S. aureus) surface protein GapC, gapC gene of S. aureus was amplified from strain BMSA/855/23-1 by PCR, and was inserted into pQE-30 vector subsequently. The recombinant plasmid, designated as pQE/gapC, was transformed into E. coli strain M15 (pREP4). The recombinant GapC fusion proein was successfully expressed in E. coli M15 induced with IPTG and its GAPDH activity was confirmed by GAPDH activity assay. Then, the recombinant GapC protein, inactivated S. aureus whole cell and placebo (PBS) were administrated to healthy rabbits respectively. The IgG antibody titers, concentration of IFN-gamma and IL-4 cytokines in immunized rabbit sera were measured with Enzyme-Linked Immunosorbnent Assay (ELISA). Finally, immunized rabbits were challenged with S. aureus strain Wood46 to evaluate the immunoprotection. The IgG antibody titers against GapC and whole cell in rabbit sera reached their peaks at day 28 after boost immunization (1:64,000). The concentration of IL-4 and IFN-gamma in GapC groups rabbit sera increased significantly (P<0.05) at day 14 after boost immunization, while the concentration of those in whole cell group did not increase (P>0.05) compared with the placebo group. 4 rabbits in 5 of the protein immunized group were protected against challenge with 1 x 10(8) CFU S. aureus. The results above indicate that the expressed recombinant GapC protein have high GAPDH activity and immunogenicity, can also protect against S. aureus challenge to some extent. S. aureus GapC protein could be an attractive target for further genetic engineering vaccine.