Protective immunity elicited by a divalent DNA vaccine encoding both the L7/L12 and Omp16 genes of Brucella abortus in BALB/c mice.
This study was designed to evaluate the immunogenicity and the protective efficacy of a divalent fusion DNA vaccine encoding both the Brucella abortus L7/L12 protein (ribosomal protein) and Omp16 protein (outer membrane lipoprotein), designated pcDNA3.1-L7/L12-Omp16. Intramuscular injection of this divalent DNA vaccine into BALB/c mice elicited markedly both humoral and cellular immune responses. The specific antibodies exhibited a dominance of immunoglobulin G2a (IgG2a) over IgG1. In addition, the dual-gene DNA vaccine elicited a strong T-cell proliferative response and induced a large amount of gamma interferon-producing T cells upon restimulation in vitro with recombinant fusion protein L7/L12-Omp16, suggesting the induction of a typical T-helper-1-dominated immune response in vivo. This divalent DNA vaccine could also induce a significant level of protection against challenge with the virulent strain B. abortus 544 in BALB/c mice. Furthermore, the protection level induced by the divalent DNA vaccine was significantly higher than that induced by the univalent DNA vaccines pcDNA3.1-L7/L12 or pcDNA3.1-Omp16. Taken together, the results of this study verify for the first time that the Omp16 gene can be a candidate target for a DNA vaccine against brucellosis. Additionally, a divalent genetic vaccine based on the L7/L12 and Omp16 genes can elicit a stronger cellular immune response and better immunoprotection than the relevant univalent vaccines can.
Luo
Deyan
D
State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Science, Beijing, China.
Ni
Bing
B
Li
Peng
P
Shi
Wei
W
Zhang
Songle
S
Han
Yue
Y
Mao
Liwei
L
He
Yangdong
Y
Wu
Yuzhang
Y
Wang
Xiliang
X
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics* / Q000276:immunology; D002004:Brucella Vaccine / Q000276:immunology*; D002003:Brucella abortus / Q000276:immunology*; D019556:COS Cells; D002522:Chlorocebus aethiops; D005260:Female; D007114:Immunization; D007371:Interferon-gamma / Q000096:biosynthesis; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D012269:Ribosomal Proteins / Q000235:genetics* / Q000276:immunology; D018417:Th1 Cells / Q000276:immunology; D019444:Vaccines, DNA / Q000276:immunology*
D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002004:Brucella Vaccine; D011993:Recombinant Fusion Proteins; D012269:Ribosomal Proteins; D019444:Vaccines, DNA; C016700:ribosomal protein L7-L12; D007371:Interferon-gamma