title: Interaction of a neurotropic strain of Borrelia turicatae with the cerebral microcirculation system.
abstract: Relapsing fever (RF) is a spirochetal infection characterized by relapses of a febrile illness and spirochetemia due to the sequential appearance and disappearance of isogenic serotypes in the blood. The only difference between isogenic serotypes is the variable major outer membrane lipoprotein. In the absence of specific antibody, established serotypes cause persistent infection. Studies in our laboratory indicate that another consequence of serotype switching in RF is a change in neuroinvasiveness. As the next step to elucidate this phenomenon, we studied the interaction of the neurotropic Oz1 strain of the RF agent Borrelia turicatae with the cerebral microcirculation. During persistent infection of antibody-deficient mice, we found that serotype 1 entered the brain in larger numbers and caused more severe cerebral microgliosis than isogenic serotype 2. Microscopic examination revealed binding of B. turicatae to brain microvascular endothelial cells in vivo. In vitro we found that B. turicatae associated with brain microvascular endothelial cells (BMEC) significantly more than with fibroblasts or arachnoidal cells. The binding was completely eliminated by pretreatment of BMEC with proteinase K. Using transwell chambers with BMEC barriers, we found that serotype 1 crossed into the lower compartment significantly better than serotype 2. Heat killing significantly reduced BMEC crossing but not binding. We concluded that the interaction of B. turicatae with the cerebral microcirculation involves both binding and crossing brain microvascular endothelial cells, with significant differences among isogenic serotypes.
authors.affiliation: Department of Neurology and Neuroscience, Center for the Study of Emerging Pathogens, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, 185 South Orange Avenue, MSB H506, Newark, NJ 07103, USA.
authors.forename: Nilay
authors.initials: N
authors.lastname: Sethi
authors.forename: Marie
authors.initials: M
authors.lastname: Sondey
authors.forename: Yunhong
authors.initials: Y
authors.lastname: Bai
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Kim
authors.forename: Diego
authors.initials: D
authors.lastname: Cadavid
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000382:microbiology; D001898:Borrelia / Q000145:classification / Q000472:pathogenicity* / Q000502:physiology; D001921:Brain / Q000098:blood supply* / Q000382:microbiology / Q000473:pathology; D002460:Cell Line; D002560:Cerebrovascular Circulation; D004730:Endothelium, Vascular / Q000382:microbiology / Q000473:pathology; D005260:Female; D006801:Humans; D020852:Lyme Neuroborreliosis / Q000382:microbiology / Q000473:pathology / Q000503:physiopathology; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D008833:Microcirculation / Q000382:microbiology / Q000473:pathology; D012061:Relapsing Fever / Q000382:microbiology / Q000473:pathology; D012703:Serotyping