AA-Amyloid is cleared by endogenous immunological mechanisms.
OBJECTIVE
AA amyloidosis is a complication to longstanding inflammatory diseases, but reduction of amyloid mass has been reported as the inflammation ceases. Not much is known about the endogenous factors that contribute to this amyloid resolution. Herein, we describe the dynamics of amyloid degradation and resolution in experimental murine AA-amyloidosis.


METHODS
AA-amyloidosis was induced in mice with injections of amyloid enhancing factor (AEF) and by inflammation induced with injections of silver nitrate. Resolution of amyloid deposits was monitored over time.


RESULTS
Virtually all amyloid was cleared within 34 weeks. Using the ELISA-technique, antibodies directed against protein AA were detected in animals during amyloid clearance phase and macrophages were shown to internalize amyloid. Also, passive immunization with an amyloid specific monoclonal antibody, produced by a B-cell clone recovered from an animal with advanced AA-amyloidosis, reduced amyloid development in murine AA-amyloidosis.


CONCLUSIONS
Immunoglobulins co-localize with amyloid deposits and can contribute to amyloid degradation by Fc-receptor mediated phagocytosis, and should be considered key players in the degradation process.
Department of Clinical and Experimental Medicine, Division of Cell Biology, Linköping University, Linköping, Sweden.
Sofia N
SN
Nyström
Gunilla T
GT
Westermark
D000686:Amyloidosis / Q000276:immunology* / Q000378:metabolism / Q000628:therapy; D000818:Animals; D000906:Antibodies / Q000097:blood; D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage; D005260:Female; D007116:Immunization, Passive; D007136:Immunoglobulins / Q000378:metabolism; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D051379:Mice; D058225:Plaque, Amyloid / Q000276:immunology; D000685:Serum Amyloid A Protein / Q000276:immunology / Q000378:metabolism*; D013154:Spleen / Q000378:metabolism / Q000473:pathology
D000906:Antibodies; D058846:Antibodies, Monoclonal, Murine-Derived; D007136:Immunoglobulins; D000685:Serum Amyloid A Protein