The effect of fibrinopeptides A and B on experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE) was induced in guinea-pigs and rats by sensitization with encephalitogenic antigens and adjuvant. Treatment of the experimental animals by daily intraperitoneal injections with human fibrinopeptides A and B proved to produce significant changes in the course of EAE. In the treated animals as compared to controls the clinical neurological signs of the disease wuch as the number, the severity and the duration of pareses were diminished. Furthermore, the inflammatory alterations of vasopermeability associated with extravasation of plasma proteins and oedema of the neuroparenchyma were significantly less pronounced in the fibrinopeptide-treated animals. Finally, a significantly higher titre of circulating immune complexes was observed in the serum of these animals. However, the treatment with fibrinopeptides A and B did not alter the specific immune response to the antigenic challenge. No differences in anti-basic protein and anti-brain antibody production were observed. The characteristic cellular infiltrates of EAE also showed no significant qualitative or quantitative differences between fibrinopeptide-treated animals and the saline-treated controls. These results suggest that fibrinopeptides A and B act primarily on the immunologically non-specific phase of EAE development by reducing the severity of vascular permeability alterations.