Mannose-Binding Lectin Inhibits the Motility of Pathogenic Salmonella by Affecting the Driving Forces of Motility and the Chemotactic Response.
Mannose-binding lectin (MBL) is a key pattern recognition molecule in the lectin pathway of the complement system, an important component of innate immunity. MBL functions as an opsonin which enhances the sequential immune process such as phagocytosis. We here report an inhibitory effect of MBL on the motility of pathogenic bacteria, which occurs by affecting the energy source required for motility and the signaling pathway of chemotaxis. When Salmonella cells were treated with a physiological concentration of MBL, their motile fraction and free-swimming speed decreased. Rotation assays of a single flagellum showed that the flagellar rotation rate was significantly reduced by the addition of MBL. Measurements of the intracellular pH and membrane potential revealed that MBL affected a driving force for the Salmonella flagellum, the electrochemical potential difference of protons. We also found that MBL treatment increased the reversal frequency of Salmonella flagellar rotation, which interfered with the relative positive chemotaxis toward an attractive substrate. We thus propose that the motility inhibition effect of MBL may be secondarily involved in the attack against pathogens, potentially facilitating the primary role of MBL in the complement system.
Department of Animal Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan.
Jun
0000-0002-1503-5623
J
Xu
Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan.
Shuichi
S
Nakamura
Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai, Miyagi, Japan.
Md Shafiqul
MS
Islam
Department of Immunobiology and Pathogenic Biology, Medical School of Xi'an Jiaotong University, Xi'an, China.
Yijie
Y
Guo
Department of Animal Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan.
Kohei
K
Ihara
Department of Animal Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan.
Rintaro
R
Tomioka
Department of Animal Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan.
Mizuki
M
Masuda
Department of Animal Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan.
Hiroshi
H
Yoneyama
Department of Animal Microbiology, Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan.
Emiko
E
Isogai
D002633:Chemotaxis / Q000187:drug effects* / Q000502:physiology; D003593:Cytoplasm / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005407:Flagella / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D037601:Mannose-Binding Lectin / Q000378:metabolism / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D016253:Microscopy, Immunoelectron; D009068:Movement / Q000187:drug effects / Q000502:physiology; D011485:Protein Binding; D012399:Rotation; D019779:Salmonella enterica / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology
D037601:Mannose-Binding Lectin