[Study on immunogenicity of the N-terminal polypeptide of RTX toxin I of Actinobacillus pleuropneumoniae].
ApxI is one of the most important virulence factors of Actinobacillus pleuropneumoniae (APP). To study the immunogenicity of the ApxI, the complete coding sequence (3146bp) and its 5'-terminal 1140 bp fragment of the apxIA gene were separately cloned into the prokaryotic expression vector pET-28a, and expressed in the E. coli BL21 (DE3) with induction by IPTG. The expression products, rApxIA and rApxIAN, were present in a form of inclusion bodies and showed the same immunological reactivity as natural ApxI (nApxI) in Western-blot analysis. BALB/c mice were intraperitoneally immunized with the rApxIA, rApxIAN and nApxI respectively. The serum antibody levels of the rApxIAN immunized mice were significantly lower than those immunized with rApxIA or nApxI in an ApxI-specific ELISA, but serum neutralization test demonstrated that immunized mice with rApxIAN, rApxIA and nApxI could generate similar levels of antibodies neutralizing the hemolytic activity of the natural ApxI. The rApxIAN was able to elicite 80% protection rate against APP serovar 1 and 100% against serovar 2 when challenged at a dose of one LD50 after 2 weeks of boost immunization.
Mei
Ling
L
Division of Animal Infectious Disease in the State Key Laboratory of Agricultural Microbiology, Wuhan 430070, China.
Zhou
Rui
R
Lu
Hai-Song
HS
Bei
Wei-Cheng
WC
Liu
Wei-Hong
WH
Lin
Li-Wen
LW
Hong
Wen-Zhou
WZ
Chen
Huan-Chun
HC
D000189:Actinobacillus Infections / Q000517:prevention & control; D016977:Actinobacillus pleuropneumoniae / Q000235:genetics* / Q000276:immunology; D000818:Animals; D000906:Antibodies / Q000097:blood; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology; D003603:Cytotoxins / Q000235:genetics / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics / Q000276:immunology*; D002479:Inclusion Bodies / Q000235:genetics / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology*
D000906:Antibodies; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D001428:Bacterial Vaccines; D003603:Cytotoxins; D006460:Hemolysin Proteins; D010455:Peptides; D011994:Recombinant Proteins; C087744:ApxI toxin, Bacteria