Interaction between Borrelia burgdorferi and endothelium in vitro.

During the pathogenesis of Lyme disease, Borrelia burgdorferi spreads hematogenously from the site of a tick bite to several tissues throughout the body. The specific mechanism of spirochete emigration is presently unknown. Using cultured human umbilical vein endothelial cells, we found that Borrelia burgdorferi bound to the endothelial cells and to the subendothelial matrix. Low passage isolates adhered 22-30-fold greater than a strain maintained in culture continuously. Spirochete binding to subendothelial matrix was inhibited 48-63% by pretreatment of the matrix with anti-fibronectin antiserum. Spirochete migration across endothelial monolayers cultured on amniotic membrane was increased when the monolayers were damaged by chemical or physical means. Electron microscopic examination of spirochete-endothelial interactions demonstrated the presence of spirochetes in the intercellular junctions between endothelial cells as well as beneath the monolayers. Scanning electron microscopy identified a mechanism of transendothelial migration whereby spirochetes pass between cells into the amniotic membrane at areas where subendothelium is exposed.

Borrelia burgdorferi and other related spirochetes bind to galactocerebroside.

Spirochetes are agents of neurologic disease that may utilize specific neural cell surface molecules for adhesion. Borrelia burgdorferi, the etiologic agent of Lyme disease, bound to galactocerebroside (GalCer) in numbers that were two- to threefold greater than to ceramide and glucocerebroside, and four- to fivefold greater than to sphingosine, psychosine, sulfatide, cholesterol, and three membrane phospholipids. The adherence was greater to GalCer and ceramide with a higher content of alpha-hydroxyl fatty acids. Treponema phagedenis Reiter and Borrelia hermsii also bound to GalCer. The binding of B burgdorferi to GalCer was inhibited in a concentration-dependent manner by rabbit polyclonal and murine monoclonal antibodies to this glycosphingolipid component of myelin. The monoclonal antibody to GalCer also inhibited adhesion of the organisms to Schwann cells. Neither free D or L monosaccharides nor the lectin peanut agglutinin inhibited binding. Since B burgdorferi and other spirochetes cause neurologic disease, these results suggest a role for GalCer as a binding site in both the central and peripheral nervous systems.

Expression and distribution of parotid secretory proteins in experimental diabetes.

Previous studies of experimental diabetes have demonstrated changes in the levels of specific salivary proteins. The present study is part of a larger effort aimed at elucidating the mechanism(s) by which insulin regulates salivary protein expression in the rat parotid gland. Diabetes was induced in 2-3-month-old male Fischer 344 rats by injection of streptozotocin (STZ). After 30 days one group of rats was given insulin for 7 days. Untreated rats served as controls. As previously observed, parotid acinar cells from diabetic rats accumulated lipid and contained occasional crystalloid lysosomes. Quantitative immunogold labeling of secretory granules in diabetic glands revealed decreases of 30-60% for proline-rich-proteins (PRPs), amylase and parotid secretory protein (PSP), but labeling for acidic epididymal glycoprotein (AEG) was unchanged. The response to insulin treatment was variable: amylase and PSP labeling were partly restored, but PRP and AEG labeling showed little change. Photoaffinity labeling of cyclic AMP receptor proteins (cARP) showed changes in several tissues including a consistent increase in the diabetic parotid gland. Immunogold labeling of secretory granules with antibody to cARP was similar in control and diabetic parotids, but nuclear and cytoplasmic label was decreased in diabetic acinar cells. These results indicate that STZ-diabetes and insulin reconstitution cause variable changes in the expression of parotid secretory proteins. Changes in cARP levels suggest that the insulin and cyclic AMP pathways may interact in regulating expression of salivary secretory proteins.

[The characterization of a Spanish strain of Borrelia burgdorferi]. / Caracterización de una cepa española de Borrelia burgdorferi.

BACKGROUND: The characteristics of a Spanish strain of Borrelia burgdorferi, the spirochete which causes Lyme's disease, and which, up to the present, has not been isolated in Spain, are described. METHODS: The organism was obtained from ticks (Ixodes ricinus) from the northern part of Spain. It was studied in culture by dark field microscopy and the internal structure observed by electron transmission. The antigenic composition was analyzed under polyacrylamide electrophoresis, immunoblot and reactivity against monoclonal antibodies. Plasmid analysis was carried out by Southern blot. RESULTS: In culture the length of the organism is somewhat shorter than normal. It grows slowly and tends to autoagglutinate. It has 6-13 periplasmic flagella. The antigenic analysis of this microorganism through immunoblot and reactivity against different monoclonal antibodies showed differences with regards to other North American strains, with the most significant being the composition of certain proteins of the surface of the organism. These differences may have clinical repercussion. DNA analysis by Southern blot demonstrated slight differences in regard to the composition of plasmids compared to other strains analyzed. CONCLUSIONS: Borrelia burgdorferi exists in Spain. The isolated strain shows peculiar characteristics with respect to others analyzed. The availability of an autochthonous strain may allow more reliable serological diagnosis in Spain.