Factor H specifically capture novel Factor H-binding proteins of Streptococcus suis and contribute to the virulence of the bacteria.
Factor H (FH), a regulatory protein of the complement system, can bind specifically to factor H-binding proteins (FHBPs) of Streptococcus suis serotype 2 (SS2), which contribute to evasion of host innate immune defenses. In the present study, we aimed to identify novel FHBPs and characterize the biological functions of FH in SS2 pathogenesis. Here, a method that combined proteomics and Far-western blotting was developed to identify the surface FHBPs of SS2. With this method, fourteen potential novel FHBPs were identified among SS2 surface proteins. We selected eight newly identified proteins and further confirmed their binding activity to FH. The binding of SS2 to immobilized FH decreased dramatically after pre-incubation with anti-FHBPs polyclonal antibodies. We showed for the first time that SS2 also interact specifically with mouse FH. Furthermore, we found that FH play an important role in adherence and invasion of SS2 to HEp-2 cells. Additionally, using a mouse model of intraperitoneal challenge, we confirmed that SS2 pre-incubated with FH enhanced bacteremia and brain invasion, compared with SS2 not pretreated with FH. Taken together, this study provides a useful method to characterize the host-bacteria interactions. These results first indicated that binding of FH to the cell surface improved the adherence and invasion of SS2 to HEp-2 cells, promoting SS2 to resist killing and leading to enhance virulence.
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: 2015207024@njau.edu.cn.
Quan
Q
Li
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: 2014107080@njau.edu.cn.
Caifeng
C
Ma
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: 2015107080@njau.edu.cn.
Yang
Y
Fu
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: 625226335@qq.com.
Yanan
Y
He
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: 2013207020@njau.edu.cn.
Yanfei
Y
Yu
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: 529429075@qq.com.
Dechao
D
Du
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: yaohch@njau.edu.cn.
Huochun
H
Yao
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: lucp@njau.edu.cn.
Chengping
C
Lu
Key Lab of Animal Bacteriology, OIE Reference Lab for Swine Streptococcosis, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China. Electronic address: vszw@njau.edu.cn.
Wei
W
Zhang
D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D001422:Bacterial Adhesion / Q000276:immunology; D002352:Carrier Proteins / Q000276:immunology; D002460:Cell Line; D017242:Complement Factor H / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D054884:Host-Pathogen Interactions; D006801:Humans; D055767:Immobilized Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D057131:Immune Evasion; D007113:Immunity, Innate; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D013290:Streptococcal Infections / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D017011:Streptococcus suis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism / Q000472:pathogenicity*; D014774:Virulence
D000942:Antigens, Bacterial; C493495:CFH protein, human; D002352:Carrier Proteins; D055767:Immobilized Proteins; D008565:Membrane Proteins; D017242:Complement Factor H
Adherence; Factor H-binding proteins; Interaction; Invasion; Streptococcus suis serotype 2; Virulence