Edema-producing activity of group A streptococcal polysaccharide and its possible role in the pathogenesis of cell wall-induced polyarthritis

Edematous responses were induced in the limbs of Sprague-Dawley rats by intravenous, intraperitoneal, or intra-articular injections of group- specific polysaccharide (PS) isolated from the cell walls of group A streptococci. After intravenous injection of the edema-producing PS, vascular permeability increase (measured by 125I-human serum albumin) was detected in the limbs, but not in the heart, lungs, spleen, liver, thymus, kidney, skin, skeletal muscle, submandibular lymph nodes, mesenteric lymph nodes, or ascending colon. This indicates a selective effect on vascular endothelium of the joints. Evidence to suggest that the edema-producing activity of the PS might play an important role in the pathogenesis of cell wall-induced polyarthritis included the following: (a) the presence of edema-producing activity in arthropathogenic cell wall preparations; (b) cell wall preparations without edema-producing activity were significantly less active in inducing arthritis than were those which contained edema-producing activity; and (c) the addition of edema-producing PS to cell wall preparations increased both the incidence and the severity of arthritis.