Production of interleukin-8 (IL-8) by cultured endothelial cells in response to Borrelia burgdorferi occurs independently of secreted [corrected] IL-1 and tumor necrosis factor alpha and is required for subsequent transendothelial migration of neutrophils

Abstract

Previous studies have shown that Borrelia burgdorferi, the spirochetal agent of Lyme disease, promotes inflammation by stimulating endothelial cells to upregulate adhesion molecules for leukocytes and to produce a soluble agent that is chemotactic for neutrophils. We determined that interleukin-8 (IL-8) was the chemotactic agent for neutrophils present in conditioned media from cultured human umbilical vein endothelial cells stimulated with B. burgdorferi. As few as one spirochete per endothelial cell stimulated production of IL-8 within 8 h of coincubation. When 10 spirochetes per endothelial cell were added, IL-8 was detected after 4 h of coculture. Production of IL-8 continued in a linear fashion for at least 24 h. Neutralizing antibodies against IL-8 reduced migration of neutrophils across spirochete-stimulated endothelial monolayers by 93%. In contrast, pretreatment of neutrophils with antagonists of platelet-activating factor did not inhibit migration. Increases in production of IL-8 and expression of the adhesion molecule E-selectin by endothelial cells in response to B. burgdorferi were not inhibited by IL-1 receptor antagonist or a neutralizing monoclonal antibody directed against tumor necrosis factor alpha, used either alone or in combination. These results suggest that activation of endothelium by B. burgdorferi is not mediated through the autocrine action of secreted IL-1 or tumor necrosis factor alpha. Rather, it appears that B. burgdorferi must stimulate endothelium either by a direct signaling mechanism or by induction of a novel host-derived proinflammatory cytokine.

The relapsing fever spirochaete, Borrelia crocidurae, activates human endothelial cells and promotes the transendothelial migration of neutrophils

“…In addition, endogenous IL‐8 secreted by activated endothelial cells induces transendothelial neutrophil migration. Burns et al . (1997) have demonstrated that IL‐8 is the major soluble chemoattractant produced by HUVECs exposed to B. burgdorferi .…”

“…During the past decade, many investigators have contributed to the understanding of the inflammatory response to Lyme disease ( Schaible et al ., 1994 ; Sellati et al ., 1995 ; 1996; 1998; Wooten et al ., 1996 ; 1998; Burns et al ., 1997 ; Ebnet et al ., 1997 ; Burns and Furie, 1998). The components of innate immunity responding to the infection have been identified, and the integration of these components has been worked out in detail.…”

“…Clearly then, in their journey out of the bloodstream, these spirochaetes come into close contact with endothelial cells. Direct interaction with spirochaetal agents has been shown to activate endothelium in a proinflammatory manner and to promote the transendothelial migration of leucocytes ( Sellati et al ., 1995 ; 1996; 1998; Wooten et al ., 1996 ; 1998; Burns et al ., 1997 ; Ebnet et al ., 1997 ), suggesting that the interaction of B. crocidurae with endothelial cells may contribute to the inflammatory responses observed in relapsing fever ( Shamaei‐Tousi et al ., 1999 ). Hence, an understanding of the interaction between spirochaete and endothelial cells may be relevant to many aspects of relapsing fever borreliosis.…”

Borrelia burgdorferi induces matrix metalloproteinases by neural cultures

“…Both gelatinolytic bands disappeared when the zymography was performed in the presence of 1 mM 1,10-phenanthroline, a specific MMP inhibitor (not shown). It has been reported that endotoxin is occasionally found in the BSK II medium (Ma and Weis, 1993;Burns et al, 1997), and it could be carried as a contamination by the spirochaetes. To determine whether the MMP-9 induction is due to endotoxin bound on the spirochaete's surface, we tested whether polymyxin B, which binds to endotoxin, could inhibit the MMP-9 induction.…”

E and P Selectins Are Not Required for Resistance to Severe Murine Lyme Arthritis

“…The induction of chemokines and adhesion molecule upregulation on both endothelial and infiltrating cells is required for the infiltration of inflammatory cells, such as neutrophils, into tissues (15). Outer-surface components of B. burgdorferi have been documented to upregulate both chemokine and adhesion molecule expression on inflammatory cells (4,5,(12)(13)(14)18). Neutrophil degranulation is induced by stimulation with B. burgdorferi lipoproteins in vitro as well (10).…”