[Enhancement of antibodies to protective domain of surface protective antigen A of Erysipelothrix rhusiopathiae by DNA immunization with plasmids expressing spaA-chimeras].
OBJECTIVE
DNA vaccines expressing protective domain of surface protective antigen A(spaA)of Erysipelothrix rhusiopathiae have been relatively ineffective at generating high-titer, long-lasting, neutralizing antibodies in murine models.


METHODS
This paper report using a DNA vaccine expressing a fusion of the spaA protein and various elements, such as a secretion leader sequence from the highly expressed human gene encoding alpha1-antitrypsin (AAT), a highly soluble and stably folded domain from the rat cartilage oligomerization matrix protein (COMP), and three copies of the complement component, C3d3, to enhance the titers of neutralizing spaA-specific antibody.


RESULTS
Analysis of titers of the antibody raised in vaccinated mice at different time points indicated that immunizations with the DNA expressing pcDNA3-AAT-COMP-spaAN-3C3d((pcD-ACSC)) had higher titers than pcDNA3-spaA(N)(pcD-S) at weeks 4. Furthermore, the immune protective efficacy of the spaA-chimeras was demonstrated by lethal challenge with a virulent homologous strain 1249 against immunized mice.


CONCLUSIONS
These results suggest that using a plasmid vector containing a strong heterologous signal sequence that mediate efficient antigen secretion in vivo and a fused piece of sequence improving antigens solubility, as well as C3d3, genetic adjuvant, could enhance the antibody responses level. This approach might be an efficient way to improve the antibody level of spaA(N) DNA vaccination.
Chen
Kai-xu
KX
Key Laboratory of Molecular Biology, College of Life Science and Technology, Xinjiang University, Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, Urumqi 830046, China. chenkaixu@126.com
Li
Yi-jie
YJ
Zhang
Fu-chun
FC
Cao
Wen-yao
WY
Li
Jiang-wei
JW
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000942:Antigens, Bacterial / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D002460:Cell Line; D049109:Cell Proliferation; D004888:Erysipelothrix / Q000276:immunology*; D005260:Female; D015870:Gene Expression; D005818:Genetic Engineering; D006801:Humans; D007114:Immunization; D051379:Mice; D010957:Plasmids / Q000235:genetics*; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D013997:Time Factors; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology*
D000906:Antibodies; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D011993:Recombinant Fusion Proteins; C114457:SpaA protein, Erysipelothrix rhusiopathiae; D019444:Vaccines, DNA