Localization of Borrelia Burgdorferi in the Nervous System and Other Organs in a Nonhuman Primate Model of Lyme Disease

Abstract

SUMMARY:Lyme borreliosis is caused by infection with the spirochete Borrelia burgdorferi. Nonhuman primates inoculated with the N40 strain of B. burgdorferi develop infection of multiple tissues, including the central (CNS) and peripheral nervous system. In immunocompetent nonhuman primates, spirochetes are present in low numbers in tissues. For this reason, it has been difficult to study their localization and changes in expression of surface proteins. To further investigate this, we inoculated four immunosuppressed adult Macaca mulatta with 1 million spirochetes of the N40 strain of B. burgdorferi, and compared them with three infected immunocompetent animals and two uninfected controls. The brain, spinal cord, peripheral nerves, skeletal muscle, heart, and bladder were obtained at necropsy 4 months later. The spirochetal tissue load was first studied by polymerase chain reaction (PCR)-ELISA of the outer surface protein A (ospA) gene. Immunohistochemistry was used to study the localization and numbers of spirochetes in tissues and the expression of spirochetal proteins and to characterize the inflammatory response. Hematoxylin and eosin and trichrome stains were used to study inflammation and tissue injury. The results showed that the number of spirochetes was significantly higher in immunosuppressed animals. B. burgdorferi in the CNS localized to the leptomeninges, nerve roots, and dorsal root ganglia, but not to the parenchyma. Outside of the CNS, B. burgdorferi localized to endoneurium and to connective tissues of peripheral nerves, skeletal muscle, heart, aorta, and bladder. Although ospA, ospB, ospC, and flagellin were present at the time of inoculation, only flagellin was expressed by spirochetes in tissues 4 months later. Significant inflammation occurred only in the heart, and only immunosuppressed animals had cardiac fiber degeneration and necrosis. Plasma cells were abundant in inflammatory foci of steroid-treated animals. We concluded that B. burgdorferi has a tropism for the meninges in the CNS and for connective tissues elsewhere in the body. (Lab Invest 2000, 80:1043-1054.

Cardiac involvement in non-human primates infected with the Lyme disease spirochete Borrelia burgdorferi

“…A previous report from our group described significant cardiac inflammation and tissue injury in the heart of immunosuppressed NHPs infected with the BbN40 strain. 6 We had also seen extensive cardiac injury in the heart of mice with severe combined immunodeficiency infected with B. turicatae. 18 In humans with Lyme disease, carditis is found in up to 25%, but only rarely pathology specimens are available for examination.…”

“…6,7 Antigen retrieval by microwave heating (Dako's target retrival solution, Code No. S1699) or protease digestion (P-6911, Sigma Protease) was used with formalinfixed tissues.…”

“…5,7 PCR-ELISA for the OspA or OspB B. burgdorferi genes was performed as described. 6 All assays were run in triplicate.…”

“…[5][6][7][8][9][10] During infection of immunosuppressed NHPs inoculated with the sensu stricto strain N40 of B. burgdorferi (BbN40), we found that the heart had the most severe injury of all tissues examined and one of the highest spirochetal loads. 6 The goal of the present study was to characterize the full spectrum of Lyme carditis in the NHP model using different strains of B. burgdorferi and degrees of immunosuppression during both short-and long-term infection and after syringe or tick-inoculation. The results showed that cardiac inflammation was a consistent finding in all NHPs inoculated with BbN40 but was mild unless the animals were immunosuppressed.…”

Decreased CD57 lymphocyte subset in patients with chronic Lyme disease

“…Patients with chronic Lyme disease may have prolonged musculoskeletal or neurologic symptoms that cause significant morbidity. Studies in animals and humans with Lyme disease have shown persistence of spirochete DNA in various tissues, even after appropriate antibiotic therapy [2,3,4].…”