William J. Cromartie

Further investigation of the biological properties of streptococcal cells and their components has produced a model of erosive synovitis in rats. A single intraperitoneal injection of an aqueous suspension of whole cell sonicate of group A streptococci into Sprague-Dawley rats induced an acute arthritis which evolved into a prolonged inflammatory process characterized by several complete or partial remissions, joint deformity, and ankylosis. The toxic moiety is a peptidoglycan-polysaccharide fragment of the cell wall which persists in tissue. Histologic features of the arthritis include an acute exudative phase followed by an erosive synovitis that leads to destruction of cartilage and subchondral bone and fibrous ankylosis of the joints. The arthropathic properties of whole cell sonicates of several species of streptococci are compared along with studies of the ability of heat-killed, whole cells of groups A, B, and C streptococci to induce arthritis in rats. Whole cells induce arthritis after a latent period of 57-120 days when group A cells are injected and 7-10 days when group B cells are tested.

William James Cromartie Jr., The Effect of Stand Size and Vegetational Background on the Colonization of Cruciferous Plants by Herbivorous Insects, Journal of Applied Ecology, Vol. 12, No. 2 (Aug., 1975), pp. 517-533

The covalently bound polymers of peptidoglycan and group-specific polysaccharide (PG-APS) were isolated from the cell walls of group A streptococci. Arthritis was induced in rats with a single intraperitoneal injection of an aqueous suspension of PG-APS fragments derived by sonication. The joint lesions induced with this polydisperse suspension followed a bimodal pattern consisting of an acute phase, which reached a peak 5 days after injection and then receded, followed by a chronic, remittent, erosive arthritis lasting several months. The relative severities of the acute and chronic phases could be manipulated by selection of the size of PG-APS fragments. The fragments of PG-APS obtained by sonic treatment were resolved on the basis of size into three major populations by sucrose gradient or differential centrifugation. Based upon light scattering and gel filtration, the average molecular weight of the largest family of fragments was estimated to be about 500 x 10(6), the intermediate fragments were 50 x 10(6) daltons, and the predominant size in the smallest population was 5.3 x 10(6) daltons. The larger fragments induced negligible acute inflammation, but chronic disease became apparent 5 to 9 weeks after injection. The smallest fragments induced the most severe acute inflammation, with relatively little late, chronic joint disease. The particles of intermediate size induced moderate acute inflammation and the most severe chronic, erosive joint lesions. A single injection of fragments of the isolated peptidoglycan moiety of the PG-APS induced only a moderate acute inflammation of joints, with no apparent capacity to maintain the injury and induce chronic disease.

Peptidoglycan-polysaccharide (PG-PS) fragments were purified from cell walls of group D streptococci (Streptococcus faecium, strains ATCC 9790 and F-24) with a protocol which minimizes autolytic activity and tested for ability to induce arthritis in rats. PG-PS fragments from cell walls of other normal flora bacteria (Peptostreptococcus productus, and Propionibacterium acnes), group A streptococci, and pseudomurein-PS fragments from cell walls of Methanobacterium formicicum, were similarly purified and tested. Upon intraarticular injection into rat ankles, all PG-PS polymers induced acute inflammation; pseudomurein-PS fragments were approximately five times less active than the PG-PS preparations. After intraperitoneal injection, P. acnes PG-PS induced a minimal acute arthritis, Peptostreptococcus productus PG-PS induced a moderately severe acute joint inflammation followed by a mild chronic arthritis, and both group A and group D streptococcal PG-PS induced severe acute arthritis which evolved into chronic, erosive joint disease; pseudomurein-PS fragments were without effect, consistent with a crucial role for the PG moiety of PG-PS. Chronic arthritis induced by group D streptococcal PG-PS subsided after 60 days, whereas that induced by group A streptococcal PG-PS was still active after 128 days. The arthropathic properties of this modest number of common normal flora bacteria suggest that different PG-PS structures derived from the normal flora have the potential to induce a wide range of responses, from transient acute to chronic erosive joint disease.