Biomedical subjects
S R Line
Publications and source records attributed to S R Line.
Molecular analysis of spontaneous nephrotropic anti-laminin antibodies in an autoimmune MRL-lpr/lpr mouse.
To explore the genetic relationship between anti-laminin and anti-DNA autoantibodies (autoAb), VH gene and gene family expression were determined among autoAb derived from an individual 6-mo-old MRL-lpr/lpr mouse. Whereas 85% of the anti-DNA Ig were identified by one of two VH family probes, 7183 and VHJ558, none of the anti-laminin antibodies (Ab) examined were recognized by these probes. Subsequent V region sequence analysis of three of the anti-laminin Ab revealed that they in fact utilized a J558 VH gene (VH50). Furthermore, FR2 and CDR2 oligonucleotide probes complementary to VH50 recognized multiple anti-laminin Ab by Northern blot analysis; the FR2 probe recognized two control anti-DNA Ab, but neither probe recognized anti-DNA Ab from the same mouse. Polymerase chain reaction amplification of MRL-lpr/lpr genomic liver DNA using primers generated from VH50 and Vk50 sequences indicated that all three anti-laminin Ig have a single replacement mutation in both their VH and Vk genes. Search of the nucleic acid databases revealed that both germline VH and Vk genes are expressed unmutated by murine lupus anti-dsDNA autoAb, previously sequenced in other laboratories. Sequence comparisons suggest that differences in anti-DNA and anti-laminin reactivity may be dependent upon somatically generated differences in the CDR3 regions of the H and L chains. The results indicate that lupus anti-laminin Ab can arise from distinct B cell populations but express the same unmutated germline V region genes as lupus anti-dsDNA autoAb. They further raise the possibility that these distinct B cell populations may be activated and expanded either: independently, by distinct Ig receptor ligands such as the Ag, laminin and DNA; or simultaneously, by a common ligand such as an anti-Id recognizing a common V region epitope.
Identification and characterization of highly conserved antigenic determinants in the laminin molecule.
1. Fragments P1 and E8, the result of two different enzymatic digestions of the laminin molecule, represent interaction sites of laminin with specific cell receptors. By using negative and positive affinity purification of a rabbit antiserum against mouse laminin we have generated antibodies to these two fragments. 2. Antibodies against P1 were able to immunoprecipitate fragment E8 from elastase-digested laminin. By liquid phase competition experiments we demonstrated that the epitopes shared by P1 and E8 are a minor portion of the antigenic determinants of P1. When we checked for the presence of these shared epitopes in the human laminin molecule, they were the major fraction of the interspecies antigenic conservation. 3. A similar approach using polyclonal antibodies against human laminin has confirmed these results. 4. The shared epitopes present in both mouse and human laminin molecules seem to be spatially determined, because antibodies against these sites did not bind to fully denatured laminin. 5. Since human and mouse laminin bind to cell receptors and to other extracellular matrix proteins from both species, we conclude that these antigenic determinants may represent the actual sites for at least some of these interactions.
A murine nephritogenic monoclonal anti-DNA autoantibody binds directly to mouse laminin, the major non-collagenous protein component of the glomerular basement membrane.
The interaction of the murine monoclonal anti-DNA antibody H241 with extracellular glomerular antigens was found to be due to the binding of this antibody to laminin, the major non-collagenous protein constituent of the glomerular basement membrane. This interaction is specific, since it is inhibited by laminin, double-stranded DNA and single-stranded DNA in solution. Furthermore, the binding of H241 to mouse laminin is mediated by conformational properties of the antigen because mild denaturation of laminin strongly decreases the binding capacity of H241, while exposure of laminin to sodium dodecyl sulfate, completely abolishes this interaction. H241 is able to bind to both, human and mouse laminin. These findings are in agreement with the ligand binding specificities of the autoantibodies spontaneously produced, that differ from those generated by artificial immunization. We conclude that the polyreactivity of H241 that confers to it the capacity to bind laminin, may account for its ability to form immune deposits by binding directly to non-DNA glomerular antigens.
Diversity of collagen expression in the pleomorphic adenoma of the parotid gland.
The high diversity of collagen expression and its qualitative and quantitative aspects are demonstrated in pleomorphic adenoma using electron microscopy and specific histochemical methods. Great variability was observed in the amount, distribution and characteristics of the collagen found in the various types of tissue normally present in this tumour. Both deficient polymerization and hyperpolymerization of collagen and the occurrence of desmoplasia were observed. Evidence is presented to suggest a role for localized collagenolysis in the invasiveness of this neoplasia.
A note on the histochemical and morphological characterization of the asbestoid degeneration of cartilage.
Using only one histologic preparation and under the light microscope, the simple Picrosirius-polarization method permitted the histochemical characterization of the collagenous nature of amianthoid fibers in file cases of salivary gland tumors. In this regard the foregoing results agree with the electron microscopic and X-ray diffraction observations recorded in the literature. Not only did the Picrosirius-polarization method permit the precise characterization of the collagenous nature of asbestoid change but it was also useful for studying the degree of collagen polymerization in the lesion. Collagen molecules in the amianthoid fibers showed hyperpolymerization whereas the molecules in the compact areas were disoriented. Since the foregoing results demonstrate that the Picrosirius-polarization method is a simple and sensitive procedure for detecting asbestoid change in cartilage sections obtained from paraffin-embedded tissues, the usefulness of this technique for studying file cases is evident.
The use of tissue conditioner or zinc oxide and eugenol impression paste in the excision of epulis fissurata.
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Purification of the neurite outgrowth promoting fragment of mouse laminin.
A method for isolation of the neurite outgrowth promoting fragment of mouse laminin (fragment 8) is described in this paper. Besides producing excellent yields, this method was shown to be fast and practical, since it is based on a single step which consists in an ion exchange chromatography of elastase digested laminin.
Expression of collagen and elastic fibers in duct-ligated submandibular glands of mice.
Atrophy of salivary glands may occur by ductal obstruction caused by calculus, infection or neoplastic processes, or as consequence of systemic diseases and aging. In the present work, we have used histochemical methods to study the expression of elastic and collagen fibers during experimental atrophy of the submandibular gland of mice. Glandular atrophy was accompanied by a rapid increase in collagen deposition in both septal and intralobular regions. The expression of elastic fibers was not significantly altered during atrophy: a discrete increase of elastic fibers was noted only around ductal structures. The results showed that experimental ductal obstruction is a useful in vivo model to study molecular events that take part in the remodeling of the extracellular matrix during atrophy of salivary glands.