ABSTRACT: The overall goal of these experiments was to determine how human cells respond to ontegrin binding by Borrelia burgdorferi. Lyme disease is the most common vector-borne infection in the Northern hemisphere, yet little is understood about the pathogenic mechanisms of the causative agent, Borrelia burgdorferi. Cells in culture were infected with the bacteria that do and do not express the beta3 integrin ligand P66, which are otherwise isogenic. As additional controls, uninfected cells were also included in the analyses. The cell line used for primary data analyses provided here was Ea.hy926, a macrovascular line (Edgell, C. J.,et al. 1990. Endothelium specific Weibel-Palade bodies in a continuous human cell line, EA.hy926. In vitro Cell. & Dev. Biol. 26:1167-1172, and Edgell, C. J., et al. 1983. Permanent cell line expressing human factor VIII-related antigen established by hybridization. Proc. Natl. Acad. Sci. 80:3734-3737). In addition, the human microvascular endothelial cell line HMEC (Ades et al, 1992. HMEC-1: establishment of an immortalized human microvascular endothelial cell line. J Invest Dermatol. 99:683-690) was used. Epithelial cells HEK-293 (which does not express b3 integrins) and HEK-293 transfected to express integrin ?v?3 were also analyzed. Infection times were 1 hour or 3 hours for cells lifted with EDTA and washed prior to bacterial infection, or 3, 6, and 24 hours for samples in which the bacteria were added to adherent cells. RNA was harvested and reverse transcribed. Labeled cDNAs were used to probe 2 color arrays. In each of at least three biological replicate experiments, for each time point, the following comparisons were made. First, cells infected with B. burgdorferi with a marker inserted adjacent to the p66 gene (p66+) were compared to uninfected cells. Second, cells infected with the p66 gene interrupted by the marker (Coburn, J. and Cugini, C. (2003) Targeted mutation of P66 of Borrelia burgdorferi disrupts attachment to integrin ?v?3. Proc. Natl. Acad. Sci. 100:7301-7306) the mutant-infected cells were compared to the uninfected cells. In some experiments, cells infected with p66+ were compared to cells infected with the p66- mutant. Arrays used were HEEBO arrays purchased from Microarrays Inc. (Nashville, TN). Ea.hy926 or HMEC endothelial cell lines, or HEK-293 epithelial cells, or transfected HEK-293 derivative expressing integrin avb3