E-selectin-dependent neutrophil adhesion to Rickettsia rickettsii-infected endothelial cells

• Published in: Blood 1993-05, Vol.81 (9), p.2406-2412
• Main Authors: SPORN, L. A, LAWRENCE, S. O, SILVERMAN, D. J, MARDER, V. J
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Cell Adhesion - drug effects; Cell Adhesion - physiology; Cell Adhesion Molecules - analysis; Cell Adhesion Molecules - biosynthesis; Cell Adhesion Molecules - physiology; Cell interactions, adhesion; Cell Membrane - drug effects; Cell Membrane - physiology; Cells, Cultured; Cycloheximide - pharmacology; E-Selectin; Endothelium, Vascular - drug effects; Endothelium, Vascular - microbiology; Endothelium, Vascular - physiology; Flow Cytometry; Formaldehyde - pharmacology; Fundamental and applied biological sciences. Psychology; Humans; Kinetics; Leukemia, Promyelocytic, Acute; Molecular and cellular biology; Neutrophils - drug effects; Neutrophils - physiology; Recombinant Proteins - pharmacology; Rickettsia rickettsii - physiology; Time Factors; Tumor Cells, Cultured; Tumor Necrosis Factor-alpha - pharmacology; Umbilical Veins; Vero Cells
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V81.9.2406.2406

Increased neutrophil or HL60 cell adhesion to Rickettsia rickettsii-infected endothelial cells (ECs) was observed at 6 to 8 hours after the initiation of infection, diminishing by 24 hours. Similar increases were observed using formaldehyde-fixed neutrophils. Cellular association and likely the intracellular presence of rickettsiae was required for enhanced neutrophil adhesion, because culture medium conditioned by infected cells or rickettsiae rendered noninfective by pretreatment with tetracycline were ineffective at inducing neutrophil adhesion. Increases in neutrophil adhesion caused by infection were blocked by pretreatment of ECs with cycloheximide, suggesting the involvement of new protein synthesis in the cells' response. Flow cytometric analysis of infected cells showed increases in cell surface expression of E-selectin compared with uninfected control cells. Furthermore, incubation of 6- to 8-hour infected cells with a blocking monoclonal antibody against E-selectin (BB11) inhibited neutrophil adhesion an average of 61%. These results suggest the involvement of E-selectin in neutrophil adhesion to infected ECs occurring early in the course of the infection process. EC-initiated recruitment of neutrophil adhesion during rickettsiae infection could contribute to the pathologic changes associated with Rocky Mountain Spotted Fever.