Restoration of the impaired balance between pro-and antiinflammatory cytokines should provide effective treatment of rheumatoid arthritis. Gene therapy has been proposed as an approach for delivery of therapeutic proteins to arthritic joints. Here, we examined the efficacy of antiinflammatory gene therapy in bacterial cell wall-induced arthritis in rats. Human secreted interleukin 1 receptor antagonist (sIL-1ra) was expressed in joints of rats with recurrent bacterial cell wall-induced arthritis by using ex vivo gene transfer. To achieve this, primary synoviocytes were transduced in culture with a retroviral vector carrying the sIL-lra cDNA. Transduced cells were engrafted in ankle joints of animals prior to reactivation of arthritis. Animals in control groups were engrafted with synoviocytes transduced with lacZ and neo marker genes. Cells continued to express transferred genes for at least 9 days after engraftment. We found that gene transfer of sIL-lra significantly suppressed the severity of recurrence of arthritis, as assessed by measuring joint swelling and by the gross-observation score, and attenuated but did not abolish erosion of cartilage and bone. The effect of intraarticularly expressed sIL-lra was essentially local, as there was no significant difference in severity of recurrence between unengrafted contralateral joints in control and experimental groups. We estimate that locally expressed sIL-lra was about four orders of magnitude more therapeutically efficient than systemically administered recombinant sIL-lra protein. These findings provide experimental evidence for the feasibility of antiinflammatory gene therapy for arthritis.

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 106, the intermediate fragments were 50 x 106 daltons, and the predominant size in the smallest population was 5.3 x 106 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 ofjoints, with no apparent capacity to maintain the injury and induce chronic disease.

to prepare cell wall fragments which, on the basis of past I studies of the group A streptococcal PG-PS, would be most likely to induce chronic arthritis. PG-PS polymers were purified from two strains of Streptococcus faecium (group D), which is commonly isolated from human feces (44), and the anaerobes Peptostreptococcus productus, one of the 10 bacterial species most commonly isolated from human feces (23), and Propionibacterium acnes, a common isolate from human skin (30) and feces (23). The chemical compositions, in vitro lysozyme sensitivities, and arthropathic activities of these various cell wall polymers are described in this report. MATERIALS AND METHODS Bacterial strains. The following bacterial strains were used: Streptococcus pyogenes (group A, type 3) strain D-58, S. faecium (group D) strain F-24, S. faecium (group D) strain ATCC 9790 (obtained from G.

Seven genes have been identified with differential expression patterns in terms of disease process (osteoarthritis vs rheumatoid arthritis), state of activation (resting vs cytokine activation) and anatomical location (synovium vs skin). Four of these genes, TFPI2, GRObeta (CXCL2), MnSOD and GCP-2 (CXCL6), were selectively overexpressed in osteoarthritis fibroblasts rather than rheumatoid fibroblasts. While these differences may represent differential behaviour of synovial fibroblasts in in vitro culture, these observations suggest that TFPI2, GRObeta (CXCL2), MnSOD and GCP-2 (CXCL6) may represent new targets for treatments specifically tailored to osteoarthritis.