scholarly journals Cytoadherence of Babesia bovis-Infected Erythrocytes to Bovine Brain Capillary Endothelial Cells Provides an In Vitro Model for Sequestration

1999 ◽  
Vol 67 (8) ◽  
pp. 3921-3928 ◽  
Author(s):  
Roberta M. O’Connor ◽  
Jennifer A. Long ◽  
David R. Allred

ABSTRACT Babesia bovis, an intraerythrocytic parasite of cattle, is sequestered in the host microvasculature, a behavior associated with cerebral and vascular complications of this disease. Despite the importance of this behavior to disease etiology, the underlying mechanisms have not yet been investigated. To study the components involved in sequestration, B. bovis parasites that induce adhesion of the infected erythrocytes (IRBCs) to bovine brain capillary endothelial cells (BBEC) in vitro were isolated. Two clonal lines, CD7A+I+ and CE11A+I−, were derived from a cytoadherent, monoclonal antibody 4D9.1G1-reactive parasite population. This antibody recognizes a variant, surface-exposed epitope of the variant erythrocyte surface antigen 1 (VESA1) of B. bovisIRBCs. Both clonal lines were cytoadhesive to BBEC and two other bovine endothelial cell lines but not to COS7 cells, FBK-4 cells, C32 melanoma cells, or bovine brain pericytes. By transmission electron microscopy, IRBCs were observed to bind to BBEC via the knobby protrusions on the IRBC surface, indicating involvement of components associated with these structures. Inhibition of protein export in intact, trypsinized IRBCs ablated both erythrocyte surface reexpression of parasite protein and cytoadhesion. IRBCs allowed to recover surface antigen expression regained the ability to bind endothelial cells, demonstrating that parasite protein export is required for cytoadhesion. We propose the use of this assay as an in vitro model to study the components involved in B. bovis cytoadherence and sequestration.

1995 ◽  
Vol 17 (1) ◽  
pp. 25-32 ◽  
Author(s):  
D. J. Bobilya ◽  
K. D'Amour ◽  
A. Palmer ◽  
C. Skeffington ◽  
N. Therrien ◽  
...  

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Rahul Basu ◽  
Vinod Nair ◽  
Clayton W. Winkler ◽  
Tyson A. Woods ◽  
Iain D. C. Fraser ◽  
...  

Abstract Background A key factor in the development of viral encephalitis is a virus crossing the blood-brain barrier (BBB). We have previously shown that age-related susceptibility of mice to the La Crosse virus (LACV), the leading cause of pediatric arbovirus encephalitis in the USA, was associated with the ability of the virus to cross the BBB. LACV infection in weanling mice (aged around 3 weeks) results in vascular leakage in the olfactory bulb/tract (OB/OT) region of the brain, which is not observed in adult mice aged > 6–8 weeks. Thus, we studied age-specific differences in the response of brain capillary endothelial cells (BCECs) to LACV infection. Methods To examine mechanisms of LACV-induced BBB breakdown and infection of the CNS, we analyzed BCECs directly isolated from weanling and adult mice as well as established a model where these cells were infected in vitro and cultured for a short period to determine susceptibility to virus infection and cell death. Additionally, we utilized correlative light electron microscopy (CLEM) to examine whether changes in cell morphology and function were also observed in BCECs in vivo. Results BCECs from weanling, but not adult mice, had detectable infection after several days in culture when taken ex vivo from infected mice suggesting that these cells could be infected in vitro. Further analysis of BCECs from uninfected mice, infected in vitro, showed that weanling BCECs were more susceptible to virus infection than adult BCECs, with higher levels of infected cells, released virus as well as cytopathic effects (CPE) and cell death. Although direct LACV infection is not detected in the weanling BCECs, CLEM analysis of brain tissue from weanling mice indicated that LACV infection induced significant cerebrovascular damage which allowed virus-sized particles to enter the brain parenchyma. Conclusions These findings indicate that BCECs isolated from adult and weanling mice have differential viral load, infectivity, and susceptibility to LACV. These age-related differences in susceptibility may strongly influence LACV-induced BBB leakage and neurovascular damage allowing virus invasion of the CNS and the development of neurological disease.


1988 ◽  
Vol 16 (1) ◽  
pp. 48-53
Author(s):  
Marina Ziche ◽  
Lucia Morbidelli ◽  
Annalisa Rubino ◽  
Piero Dolara ◽  
Stefano Bianchi ◽  
...  

Polymorphonuclear neutrophil (PMN) interaction with vascular endothelial cells is the initial event in the migration of neutrophils through blood vessel walls before reaching inflammation sites in tissues. The interaction between fibroblasts and endothelial cells and their extracellular matrices might be modulated by the activation of neutrophils that occurs at inflammatory reaction sites. We have used an in vitro model to study PMN function, measuring the adhesion of human PMNs to capillary endothelial cells and fibroblasts grown in culture and to their extracellular matrices. The interaction was measured in basal conditions and in the presence of the chemotactic effector, formyl-methionyl-leucyl-phenylalanine (FMLP at the concentration of 10 7M). Adhesion was expressed by the number of adherent PMNs/mm2 on a histological specimen. Moreover, we have adapted a program for image analysis to quantify neutrophil adhesion. Three times more PMNs adhered to matrices than to monolayers, and adherence could be increased by the presence of 10-7M FMLP, except in the case of fibroblast monolayers. We found a good correlation between microscopic observation and computerised image analysis measuring PMN adhesiveness to extracellular matrices.


Life Sciences ◽  
1992 ◽  
Vol 51 (18) ◽  
pp. 1427-1437 ◽  
Author(s):  
Akira Tsuji ◽  
Tetsuya Terasaki ◽  
Yasushi Takabatake ◽  
Yoshiyuki Tenda ◽  
Ikumi Tamai ◽  
...  

1991 ◽  
pp. 249-249
Author(s):  
M. P. Dehouck ◽  
M. Chamoux ◽  
J. C. Fruchart ◽  
G. Spik ◽  
J. Montreuil ◽  
...  

1996 ◽  
Vol 270 (4) ◽  
pp. H1149-H1158 ◽  
Author(s):  
L. Descamps ◽  
M. P. Dehouck ◽  
G. Torpier ◽  
R. Cecchelli

A cell culture model of the blood-brain barrier consisting of a coculture of bovine brain capillary endothelial cells (BBCECs) and astrocytes has been used to examine the mechanism of iron transport to the brain. Binding experiments showed that BBCECs express 35,000 high-affinity (concn at 50% receptor saturation = 11.3 +/- 2.1 nM) transferin (Tf) receptors per cell. In contrast to apo-transferrin (apoTf) we observed a specific transport of holo-transferrin (holoTf) across BBCECs. This transport was inhibited completely at low temperature. Moreover, the anti-Tf receptor antibody (OX-26) competitively inhibited holoTf uptake by BBCECs. Pulse-chase experiments demonstrated that only 10% of Tf was recycled to the luminal side of the cells, whereas the majority of Tf was transcytosed to the abluminal side; double-labeling experiments clearly demonstrated that iron crosses BBCECs bound to Tf. No intraendothelial degradation of Tf was observed, suggesting that the intraendothelial pathway through BBCECs bypasses the lysosomal compartment. These results clearly show that the iron-Tf complex is transcytosed across brain capillary endothelial cells by a receptor-mediated pathway without any degradation.


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