Effect of myosin B on guinea pig muscles--light microscopic and immunological aspects.

Experimental myositis was induced in guinea pigs by multiple inoculations with Myosin B fraction of the rabbit skeletal muscle. Quantitative histopathological features were studied and they include necrosis, central nucleation, inflammatory cellular reaction. Besides myositis, features of myocarditis were evident in 40% animals. Circulating immune complexes (CICs) in the sera of experimental animals were isolated by a polyethylene glycol (PEG) precipitation method. Presence of antimyosin B antibody in the immune complexes was characterised by an enzyme-linked immunosorbent assay. The role of circulating immune complexes in pathogenesis of experimental myositis and human polymyositis have been emphasised.