Interactions between Borrelia burgdorferi and eukaryote cells: comparative ultrastructural aspects

Area of Science:

• Microbiology
• Cell Biology
• Immunology

Background:

• Borrelia burgdorferi (Bb) is the causative agent of Lyme disease.
• Understanding host-pathogen interactions is crucial for developing effective treatments.

Purpose of the Study:

• To investigate the interaction between Borrelia burgdorferi and mammalian cells at the ultrastructural level.
• To compare the cellular responses of VERO cells, human polymorphonuclear leukocytes (PMN), and mouse peritoneal macrophages (MPM) to Bb infection.

Main Methods:

• Co-incubation of B31 Borrelia burgdorferi strain with VERO cells, human PMN, and mouse peritoneal macrophages.
• Examination of infected cells using transmission electron microscopy.

Main Results:

• Spirochete adherence to mammalian cells occurs primarily at the apical pole.
• Entry into VERO cells and MPM involves cytoplasmic membrane destruction or phagocytosis.
• Internalization into PMN occurs exclusively via phagocytosis, leading to spirochete destruction.
• Bb may alter phagosomal membranes to evade lysosomal fusion.
• Cellular cytoskeleton may facilitate Bb spread to adjacent cells.

Conclusions:

• Mouse peritoneal macrophages are not an efficient barrier against Bb.
• Human polymorphonuclear leukocytes represent a more effective barrier due to their ability to destroy Bb post-phagocytosis.