Protective immunity against Q fever induced with a recombinant P1 antigen fused with HspB of Coxiella burnetii.
The gene fragments encoding outer membrane protein 1 (P1) and heat-shock protein B (HspB) amplified from genomic DNA of Coxiella burnetii Xinqiao by PCR were inserted into prokaryotic expression vector pQE30 to construct recombinant expression plasmids pQE30/p1 and pQE30/hspB, respectively. The p1 fragment from pQE30/p1 was ligated with hspB of pQE30/hspB to construct pQE30/p1-hspB. Recombinant proteins, P1, HspB, and P1-HspB, were expressed in Escherichia coli cells transformed with pQE30/p1, pQE30/hspB, and pQE30/p1-hspB, respectively. The purified recombinant proteins and whole-cell antigen (WCA) of C. burnetii were used to immunize BALB/c mice. The antibody detection, T-cell proliferation assay, and cytokine detection demonstrated that the animals immunized with P1-HspB or WCA exhibited stronger humoral and cellular immune responses compared with animals immunized with P1 or HspB individually. Seven days after challenge of 10-fold 50% infection dose of C. burnetii, mice were euthanized and their spleens were collected. The splenic weights of mice immunized with P1-HspB or WCA were significantly lighter than that of mice immunized with P1 or HspB. By real-time PCR assay, the coxiella loads of spleens of mice immunized with P1-HspB or WCA were also significantly lower than that of mice immunized with P1 or HspB. The data from this study indicate that fusion antigen P1-HspB is a good immunogen for eliciting immunoresponses against C. burnetii, and it may be a more suitable candidate for preparing subunit vaccine against Q fever.
Li
Qingfeng
Q
Beijing Institute of Microbiology and Epidemiology, Fengtai, Beijing 100071, China.
Niu
Dongsheng
D
Wen
Bohai
B
Chen
Meiling
M
Qiu
Ling
L
Zhang
Jingbo
J
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000942:Antigens, Bacterial / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D002642:Chick Embryo; D006360:Heat-Shock Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D007111:Immunity, Cellular; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009929:Organ Size; D011778:Q Fever / Q000276:immunology / Q000517:prevention & control*; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D012290:Rickettsial Vaccines / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000382:microbiology / Q000502:physiology; D013987:Ticks / Q000382:microbiology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D006360:Heat-Shock Proteins; C112564:HspB protein, Helicobacter pylori; D011993:Recombinant Fusion Proteins; D012290:Rickettsial Vaccines