J Infect Dis. 1993 May;167,5:1074-81.Invasion of human skin fibroblasts by the Lyme disease spirochete, Borrelia burgdorferi. Klempner MS, Noring R, Rogers RA.
Division of Geographic Medicine and Infectious Diseases, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111.
The ability of Borrelia burgdorferi to attach to and invade human fibroblasts was investigated by scanning electron and confocal microscopy. By scanning electron microscopy, B. burgdorferi were tightly adherent to fibroblast monolayers after 24-48 h but were eliminated from the cell surface by treatment with ceftriaxone, 1 microgram/mL, for 5 days. Despite the absence of visible spirochetes on the cell surface after antibiotic treatment, viable B. burgdorferi were isolated from lysates of the fibroblast monolayers. B. burgdorferi were observed in the perinuclear region within human fibroblasts by laser scanning confocal microscopy.Intracellular spirochetes specifically labeled with monoclonal anti-flagellin antibody were also identified by fluorescent laser scanning confocal microscopy. These observations suggest that B. burgdorferi can adhere to, penetrate, and invade human fibroblasts in organisms that remain viable.