title: Infectivity of Borrelia burgdorferi sensu lato is unaltered in C3-deficient mice.
abstract: B. burgdorferi, B. afzelii, and B. bavariensis show resistance to mouse and human complement. B. garinii and B. valaisiana are sensitive to mouse and human complement. We evaluated whether the absence of C3 in mice influenced infectivity and pathogenicity of different Borrelia species. C3 knockout mice (C3-/-) and syngeneic C57Bl/6 wild-type (WT) mice were challenged with 5 different Borrelia species. After 2 weeks, quantitative PCR (qPCR), culture, histopathology, and immunofluorescence were performed on heart, joint, brain, bladder, and skin. Spirochaetes were detected by qPCR after infection with B. burgdorferi, B. afzelii, or B. bavariensis strains. In joints of C3-/-, but not WT mice challenged with B. burgdorferi, spirochaetes were detected by qPCR. No other significant differences between C3-/- and WT mice were seen. Histopathology demonstrated concordance between borrelia load and inflammation score. Only after B. burgdorferi and B. afzelii infection, spirochaetes were detected by immunofluorescence microscopy. B. burgdorferi was cultured from heart, joint, bladder, and skin from all mice within 2 weeks. B. afzelii and B. bavariensis grew only from heart tissue from both C3-/- and WT mice after 2-6 weeks. The infectivity and pathogenicity of complement-resistant Borrelia strains is unchanged in complement-deficient mice. Complement-susceptible strains do not become infectious in the absence of C3.
authors.affiliation: Dept. of Medical Microbiology, Centre of Infectious Diseases, Leiden University Medical Centre, PO Box 9600, 2300 RC Leiden, The Netherlands. N.D.van Burgel@LUMC.nl
authors.forename: N D
authors.initials: ND
authors.lastname: van Burgel
authors.forename: N C M
authors.initials: NC
authors.lastname: Balmus
authors.forename: E
authors.initials: E
authors.lastname: Fikrig
authors.forename: A P
authors.initials: AP
authors.lastname: van Dam
mesh_terms: D000818:Animals; D000843:Ankle Joint / Q000473:pathology; D001168:Arthritis / Q000209:etiology / Q000473:pathology; D015748:Borrelia burgdorferi Group / Q000472:pathogenicity*; D003176:Complement C3 / Q000172:deficiency*; D046508:Culture Techniques; D004198:Disease Susceptibility; D008193:Lyme Disease / Q000150:complications / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D003176:Complement C3