title: Genome-wide analysis of an avirulent strain that induces protective immunity against challenge with virulent Streptococcus suis serotype 2.
abstract: It was previously reported in China that two recent large-scale outbreaks of Streptococcus suis serotype 2 (S. suis 2) infections in human were caused by two highly virulent S. suis 2 strains, from which a novel genomic island (GEI), associated with disease onset and progression and designated 89 K, was identified. Here, an avirulent strain, 05HAS68, was isolated from a clinically healthy pig.
  
  
  
  By comparing the genomes of this avirulent strain with virulent strains, it was found that massive genomic rearrangements occurred, resulting in alterations in gene expression that caused enormous single gene gain and loss. Important virulent genes were lost, such as extracellular protein factor (ef) and suilysin (sly) and larger mutants, such as muramidase-released protein (mrp). Piglets vaccinated with the avirulent strain, 05HAS68, had increased TNF-α and IFN-γ levels in the peripheral blood and were fully protected from challenge infection with the most virulent S. suis 2 strain, 05ZYH33. Transfusion of T cells and plasma from vaccinated pigs resulted in protection of recipient animals against the 05ZYH33 challenge.
  
  
  
  These results suggest that analysis genome of the avirulent strains are instrumental in the development of vaccines and for the functional characterization of important of genetic determinants.
authors.affiliation: Translational Medicine Center, PLA Hospital No. 454, Nanjing, 210002, China. wj6373@hotmail.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Medical Microbiology and Parasitology, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China.
authors.forename: Youjun
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Department of Epidemiology, Medicinal Research Institute, Nanjing Military Command, Nanjing, 210002, China.
authors.forename: Changjun
authors.initials: C
authors.lastname: Wang
authors.affiliation: Department of Epidemiology, Medicinal Research Institute, Nanjing Military Command, Nanjing, 210002, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zheng
authors.affiliation: University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Bachar
authors.initials: B
authors.lastname: Hassan
authors.affiliation: Translational Medicine Center, PLA Hospital No. 454, Nanjing, 210002, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Zhi
authors.affiliation: Translational Medicine Center, PLA Hospital No. 454, Nanjing, 210002, China.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Li
authors.affiliation: Translational Medicine Center, PLA Hospital No. 454, Nanjing, 210002, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Yao
authors.affiliation: The Warren Alpert Medical School of Brown University, Providence, RI02912, USA.
authors.forename: Elaine
authors.initials: E
authors.lastname: He
authors.affiliation: Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY, 10065, USA.
authors.forename: Shibo
authors.initials: S
authors.lastname: Jiang
authors.affiliation: PLA Research Institute of Clinical Laboratory Medicine, Nanjing General Hospital, Nanjing Military Command, Nanjing, 210002, China. tjq85@hotmail.com.
authors.forename: Jiaqi
authors.initials: J
authors.lastname: Tang
mesh_terms: D000372:Agglutination Tests; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002681:China; D004269:DNA, Bacterial; D004195:Disease Models, Animal; D015964:Gene Expression Regulation, Bacterial; D016680:Genome, Bacterial / Q000235:genetics*; D006460:Hemolysin Proteins / Q000235:genetics; D007371:Interferon-gamma / Q000097:blood; D008297:Male; D046529:Microscopy, Electron, Transmission; D020543:Proteome / Q000032:analysis; D017422:Sequence Analysis, DNA; D065288:Serogroup; D012703:Serotyping; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology* / Q000517:prevention & control; D022541:Streptococcal Vaccines; D017011:Streptococcus suis / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification / Q000472:pathogenicity*; D034421:Sus scrofa / Q000382:microbiology; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000382:microbiology; D013601:T-Lymphocytes; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D014774:Virulence / Q000235:genetics*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C082316:Epf protein, Streptococcus suis; D006460:Hemolysin Proteins; C421489:MRP protein, Streptococcus suis; D020543:Proteome; D022541:Streptococcal Vaccines; D014409:Tumor Necrosis Factor-alpha; C104760:suilysin; D007371:Interferon-gamma