The distribution of binding sites for two lectins with different specificities was studied in adult mice by staining paraffin sections with lectins labeled either with fluorescein isothiocyanate or horseradish peroxidase. Binding sites for Dolichos b:florus agglutinin, a lectin specific to terminal aN -acetylgalactosamine residue, were detected only in several restricted regions, such as collecting tubules and Bowman's capsules of the kidney, bile ducts, pancreatic ducts, sperms, oocytes, some secreting cells, and the secreted mucin itself. Binding sites for peanut agglutinin (PNA), a lectin specific to terminal 3-galactosyl residue, were distributed more widely. However, differen-780 WATANABE, MURAMATSU, SHIRANE, UGAI Materials and Methods Mice. 129/slcp and BALB/c mice were bred in the animal facilities of Kobe University School of Medicine. Both male and female mice 4-6 weeks old were used. The institution's guide for use and care of laboratory animals was followed. Lectins. DBA labeled with fluorescein isothiocyanate (FITC-DBA, optical density (OD) 495/280, ratio = 1.05) or with horseradish peroxidase (HRP-DBA), PNA labeled with FITC (FITC-PNA, OD 495/280, ratio = 2. 1 7) or with HRP (HRP-PNA) and HRP-concanavalin A (HRP-Con A) were the products of E.Y. Laboratories, San Mateo, CA. Haptenic sugars. D-N-acetylgalactosamine (GaINAc) was the product of Sigma Chemical Co. , St. Louis, MO. o-lactose and amethyl-o-mannoside were the products of Nakarai Chemical Co. , Ja-. pan.

When rheumatoid articular cartilage samples were incubated with normal polymorphonuclear leukocytes (PMN) in vitro, large numbers of PMN were seen attached to the articular surface. As observed by electron microscopy, significant numbers of these cells invaded the cartilage tissue and phagocytosed amorphous material which presumably contained immune complexes. In control cartilage from osteoarthritic, pyogenic, and normal subjects, only a few PMN were attached to the articular surface after incubation with PMN. These results demonstrate that immune complexes trapped in the superficial region of the rheumatoid articular cartilage may play an important role in the destruction of cartilage by the release of lysosomal enzymes from PMN.

No abstract

The present experiments were designed to investigate in vitro interactions between polymorphonuclear leukocytes (PMN) and rabbit joint collagenous tissues containing trapped immune complexes. Articular cartilages and menisci from antigen-injected and control joints were incubated with normal PMN isolated from rabbit peritoneal exudates or blood. After incubation of cartilage and menisci from antigen-injected joints with PMN, large numbers of PMN became attached to the articular surface. In areas of superficial erosion, the PMN invaded the tissue several cell diameters below the articular surface. Through immunoelectron microscopy, degranulated PMN were observed in scattered areas to phagocytose amorphous material containing rabbit Ig. Following addition of PMN to control tissues, only a few PMN became attached to the articular surface. When tissues from monosodium urate-injected joints were incubated with PMN, these cells were found attached to the surface in moderate numbers, but invasion into the tissues was not seen. These studies indicate that immune complexes trapped in joint collagenous tissues may lead to enhanced release of lysosomal hydrolases.In rabbits previously immunized to a soluble antigen, intraarticular injection of the antigen results in the development of a chronic arthritis and the formation of immune complexes (IC) that are trapped within the joint collagenous tissues and persist in the inflamed joint for long periods of time (1-3). IC have also been found in the articular cartilage and menisci obtained from a majority of patients with rheumatoid arthritis (4.5). The role of the trapped IC in the maintenance of acute and chronic inflammation both in the animal model and the rheumatoid joint is unknown, but recent work from this laboratory (6) suggests that the trapped complexes are able to activate the complement system and generate mediators of inflammation. Moreover, the trapped complexes induced the formation of pannuslike inflammatory capsules in immune complex-containing menisci transferred to the suprapatellar pouches of previously immunized rabbits ( 6 ) .Henson (7,8) and Hawkins (9) have previously shown that 1C trapped on artificial membranes were able to induce the release of lysosomal hydrolases from polymorphonuclear leukocytes (PMN) permitted to interact with the 1C irreversibly trapped on such surfaces. The release of lysosomal enzymes was attributed to "re-