Monoclonal antibodies (mAbs) against the major constituents of cartilage extracellular matrix, aggrecan and link protein, were screened by indirect immunofluorescence on frozen sections of bovine spinal cord. Antibodies against aggrecan and link protein gave rise to very similar perineuronal labeling in spinal cord gray matter. Aggrecan and link protein reactivities were seen in other regions of the central nervous system (CNS), although their distributions were not always coincident. Pretreatment of the tissue section with Streptomyces hyaluronidase, which is hyaluronate-specific, led to the loss of both reactivities. On Western blots, anti-aggrecan mAbs reacted with a large chondroitin sulfate proteoglycan. The chondroitinase-treated CNS proteoglycan co-migrated with the chondroitinase- and keratanase-treated cartilage proteoglycan. In CNS tissue homogenates, the addition of Streptomyces hyaluronidase brought about the release of the proteoglycan from the tissue. Anti-link protein mAbs were reactive with two species in the bovine CNS, the mobilities of which were very similar to those of the cartilage link proteins. The release of these species from the tissue required hyaluronidase. A rabbit antiserum against aggrecan was used to identify a similar proteoglycan in the rat CNS. In spinal cord-derived cell cultures, the labeled material was associated with astrocytes. An aggrecan cDNA hybridized to a 9.5 kb mRNA in the rat CNS. We conclude that the perineuronal matrix consists, in part, of a hyaluronate-bound aggrecan-like proteoglycan and link proteins, and that the former is produced by astrocytes.
Objective. Autoimmune diseases predominantly affect women, suggesting that female sex hormones may play a role in the pathogenesis of such diseases. We have previously shown that persistent mild-to-moderate elevations in serum prolactin levels induce a break in self tolerance in mice with a BALB/c genetic background. The aim of this study was to evaluate the effects of hyperprolactinemia on the mechanisms of B cell tolerance induction.Methods. Effects of prolactin on splenic B cell subsets were studied in female BALB/c mice. B cell receptor ( Conclusion. Persistently elevated serum prolactin levels interfere with B cell tolerance induction by impairing BCR-mediated clonal deletion, deregulating receptor editing, and decreasing the threshold for activation of anergic B cells, thereby promoting autoreactivity.
Serum levels of antibody to native DNA (nDNA) in patients with systemic lupus erythematosus (SLE) correlate with disease activity. We describe a sensitive, simple and rapid assay for these antibodies based on the observation that %-labeled nDNA passes through Millipore filters while jHnDNA complexed with specific antibody is retained. The simplicity and rapidity of this assay should allow general utilization of serum anti-nDNA antibody determinations for monitoring disease activity in patients with SLE.Although antibodies to a wide variety of polynucleotides have been detected in sera of patients with systemic lupus erythematosus (SLE) ( l ) , antibodies to native (doublestranded) DNA (nDNA) appear to be of special significance since serum levels of this antibody have been shown to correlate with disease activity, particularly with the activity of nephritis (1-6). The original technics used to demonstrate antibodies to nDNA, including precipitation, complement fixation, immunofluorescence and hemagglutination (7-12), Submitted for publication Sept 26, 1972; accepted Nov 13, 1972. are limited in their potential usefulness by their lack of sensitivity, the variation in capacity of antibodies to produce these secondary reactions (13) and the presence of anticomplementary activity in many SLE sera. The Farr (ammonium sulfate precipitation) technic for measuring serum DNA-binding activity overcomes many of these limitations (6, 14), but it is technically cumbersome and too time consuming for routine clinical use.We have developed a new method for measuring antibodies to nDNA which is sensitive, rapid and simple to perform. This assay is based on the observation that nDNA passes through cellulose nitrate filters while complexes of nDNA with antibody do not. The addition of radioactively labeled nDN.4 to sera containing antibodies to nDNA leads to the formation of a complex which is retained by cellulose nitrate filters. The amount of radioactivity retained by the filter is directly related to the level of antinDNA antibodies present in the test serum.
A B S T R A C T Extracts of human peripheral blood polymorphonuclear leukocyte granules, and two purified proteases derived from such extracts, an elastase and a chymotrypsin-like enzyme, degrade isolated bovine nasal cartilage proteoglycan at neutral pH. Viscosity studies indicate that the leukocyte granule extracts lack hyaluronidase activity and that their degradative effect on proteoglycan at physiological pH is due entirely to proteolytic action. Sepharose 4B gel chromatography and SDS-polyacrylamide gel electrophoresis of proteoglycan fractions treated with leukocyte granule enzymes at pH 7.0 indicate that they degrade one of the proteoglycan link proteins, release a fragment from the hyaluronic acid-binding portion of the proteoglycan subunit core protein, and break down the remainder of the proteoglycan subunit molecule into peptide fragments with varying numbers of chondroitin sulfate chains. Immunodiffusion studies indicate that the antigenic determinants of the proteoglycan subunit core protein and the link proteins survive treatment with granule proteases. Similar degradation of human articular cartilage proteoglycan by granule neutral proteases can be presumed to occur, in view of the similarity of structure of human articular and bovine nasal cartilage proteoglycans. The release of granule enzymes in the course of neutrophil-mediated inflammation can thus result in the Dr. Feinstein's permanent address is:
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