Myelin phagocytosis in Wallerian degeneration of peripheral nerves depends on silica-sensitive, bg/bg-negative and Fc-positive monocytes.
Previous experiments with nerves enclosed in millipore diffusion chambers had shown that myelin degradation during Wallerian degeneration depends on invasion by non-resident cells. The present study was aimed at a more precise identification of the invading cell population. Monoclonal antibody studies of degenerating nerves showed many cells with the Fc marker; cells having the Lyt-1, Lyt-2, Ia or Mac-1 markers were sparse or absent. Nerves transplanted into mice of the Chediak-Higashi bg/bg strain were invaded by cells lacking the bg/bg marker (giant lysosomes), while cotransplanted muscle tissue was invaded by cells with the bg/bg marker. Blocking monocytes with silica reduced both cell invasion and myelin degradation in degenerating nerves. These observations show that Wallerian degeneration of peripheral nerve fibers involves a subset of monocytes which are silica-sensitive and have Fc receptors but no bg/bg giant lysosomes.
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D008247:Lysosomes / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000276:immunology / Q000502:physiology* / Q000648:ultrastructure; D009186:Myelin Sheath; D009410:Nerve Degeneration; D010587:Phagocytosis / Q000187:drug effects; D012822:Silicon Dioxide / Q000494:pharmacology; D014855:Wallerian Degeneration
D000954:Antigens, Surface; D012822:Silicon Dioxide