title: The live attenuated Actinobacillus pleuropneumoniae triple-deletion mutant ΔapxIC ΔapxIIC ΔapxIV-ORF1 strain, SLW05, Immunizes pigs against lethal challenge with Haemophilus parasuis.
abstract: Haemophilus parasuis and Actinobacillus pleuropneumoniae both belong to the family Pasteurellaceae and are major respiratory pathogens that cause large economic losses in the pig industry worldwide. We previously constructed an attenuated A. pleuropneumoniae serovar 1 live vaccine prototype, SLW05 (ΔapxIC ΔapxIIC ΔapxIV-ORF1), which is able to produce nontoxic but immunogenic ApxIA, ApxIIA, and ApxIVA. This triple-deletion mutant strain was shown to elicit protective immunity against virulent A. pleuropneumoniae. In the present study, we investigated whether immunization with SLW05 could also protect against lethal challenge with virulent H. parasuis SH0165 (serovar 5) or MD0322 (serovar 4). The SLW05 strain was found to elicit a strong humoral antibody response in pigs and to confer significant protection against challenge with a lethal dose of H. parasuis SH0165 or MD0322. IgG subtype analysis revealed that SLW05 induces a bias toward a Th1-type immune response and stimulates interleukin 2 (IL-2) and gamma interferon (IFN-γ) production. Moreover, antisera from SLW05-vaccinated pigs efficiently inhibited both A. pleuropneumoniae and H. parasuis growth in a whole-blood assay. This is the first report that a live attenuated A. pleuropneumoniae vaccine with SLW05 can protect against lethal H. parasuis infection, which provides a novel approach for developing an attenuated H. parasuis vaccine.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Shulin
authors.initials: S
authors.lastname: Fu
authors.forename: Jiwen
authors.initials: J
authors.lastname: Ou
authors.forename: Minmin
authors.initials: M
authors.lastname: Zhang
authors.forename: Juan
authors.initials: J
authors.lastname: Xu
authors.forename: Huazhen
authors.initials: H
authors.lastname: Liu
authors.forename: Jinlin
authors.initials: J
authors.lastname: Liu
authors.forename: Fangyan
authors.initials: F
authors.lastname: Yuan
authors.forename: Huanchun
authors.initials: H
authors.lastname: Chen
authors.forename: Weicheng
authors.initials: W
authors.lastname: Bei
mesh_terms: D000189:Actinobacillus Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D016977:Actinobacillus pleuropneumoniae / Q000235:genetics / Q000276:immunology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology; D001428:Bacterial Vaccines / Q000276:immunology*; D006192:Haemophilus Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D044137:Haemophilus parasuis / Q000276:immunology*; D006460:Hemolysin Proteins / Q000235:genetics; D007371:Interferon-gamma / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D017384:Sequence Deletion / Q000235:genetics; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control; D014613:Vaccines, Attenuated / Q000276:immunology / Q000627:therapeutic use
chemical_list: D000907:Antibodies, Bacterial; C085361:ApxII toxin, bacteria; C122177:ApxIVA protein, Actinobacillus pleuropneumoniae; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D006460:Hemolysin Proteins; D007376:Interleukin-2; D014613:Vaccines, Attenuated; C087744:ApxI toxin, Bacteria; D007371:Interferon-gamma