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Query: UMLS:C0016632 (Fox)
 1,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mice immunized with human collagen IV develop either antibody responses or T-cell proliferative responses as a function of the MHC genotype of the immunized mice. CD4+ T cells, similar to Th1 and Th2 cells, participate in these two types of responses, with CD4+ T-cell proliferative responses associating with IL-2 and IFN gamma release, and antibody production associating with CD4+ T-cell IL-4 and IL-5 release. Thus it would appear that the same antigen can induce responses consistent with either cell-mediated or humoral immunity depending on MHC class II genotype. In attempting to understand how MHC genotype controls the class of immunity observed several models are discussed. It was proposed, based on results obtained upon priming with human collagen IV, that the activation of Th1 and Th2 responses may be regulated at several levels (presentation by different APCs, presentation of different densities of the T-cell receptor ligand and presentation of different T-cell epitopes). With the identification of the peptide recognized by the CD4+ T cells, it was clear that the inability to induce Th1 responses in H-2b and the inability to induce Th2 responses in H-2s could not be accounted for by the failure to generate an immunodominant peptide during processing or the failure of the peptides to bind to the MHC class II molecules. Furthermore, the difference in the type of response generated could not be explained by the use of different peptides of the human collagen IV molecule in the two mouse strains, as a single peptide will induce both types of CD4+ T-cell response. However, it cannot be ruled out that the a2 peptide-class II interaction forms different T-cell ligands in the two strains either because the two class II MHC molecules are different or that the peptide is processed and reveals a different antigenic activity (Fox et al. 1988). Perhaps the most important finding from the peptide studies is that the lack of proliferative response in H-2b mice is not absolute, but can be overcome either by priming with high doses of the a2 peptide or by increasing the amount of peptide needed to elicit a recall response. It seems reasonable to speculate that changes in the dose required for priming Th1 or Th2 responses may reflect differences in the activation requirements of the two types of cells with Th1 cells requiring a high ligand density and Th2 cells a low ligand density.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Selective activation of Th1- and Th2-like cells in vivo--response to human collagen IV. 168 84

The collagenase domain of bovine glomerular basement membrane was isolated in soluble form after limited digestion with pepsin. Gel filtration chromatography of the domain under denaturing conditions revealed that most of the polypeptide constituents exhibit apparent molecular weights greater than the type I collagen beta-chain, while approximately 15% are similar in size to that of alpha-chain. Carboxymethyl cellulose chromatography of the alpha-size region revealed that 70% of the protein was polypeptide XIV, as previously designated (West, T. W., Fox, J. W., Jodlowski, M., Freytag, J. W., and Hudson, B. G. (1980) J. Biol. Chem. 255, 10451-10459). This polypeptide exhibits an apparent molecular weight of 102,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. An absolute molecular weight value of 86,000 was determined by sedimentation equilibrium ultracentrifugation in 6 M guanidine hydrochloride. About 15% of the mass is carbohydrate which exists in the form of glucosylgalactosylhydroxylysine. Thus, the polypeptide backbone has a molecular weight of 73,000, a value which is considerably smaller than the alpha-chains of classical collagen. The amino acid and carbohydrate composition and cyanogen bromide patterns indicate that polypeptide XIV has a structure similar to that of C-chain or alpha 1 (IV) collagen which has been identified in other tissues. In addition, the cyanogen bromide pattern of the entire collagenous domain is similar to that of polypeptide XIV, suggesting that the latter is a structural segment of many of the higher molecular weight components.
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PMID:Bovine glomerular basement membrane. Characterization of an alpha-size collagenous polypeptide. 725 9

Utrophin is a component of the platelet membrane cytoskeleton and participates in cytoskeletal reorganization (Earnest, J. P., Santos, G. F., Zuerbig, S., and Fox, J. E. B. (1995) J. Biol. Chem. 270, 27259-27265). Although platelets do not contain dystrophin, the identification of smaller C-terminal isoforms of dystrophin, including Dp71, which are expressed in a wide range of nonmuscle tissues and cell lines, has not been investigated. In this report, we have identified Dp71 protein variants of 55-60 kDa (designated Dp71Delta(110)) in the membrane cytoskeleton of human platelets. Both Dp71Delta(110) and utrophin sediment from lysed platelets along with the high speed detergent-insoluble pellet, which contains components of the membrane cytoskeleton. Like the membrane cytoskeletal proteins vinculin and spectrin, Dp71Delta(110) and utrophin redistributed from the high speed detergent-insoluble pellet to the integrin-rich low speed pellet of thrombin-stimulated platelets. Immunoelectron microscopy provided further evidence that Dp71Delta(110) was localized to the submembranous cytoskeleton. In addition to Dp71Delta(110), platelets contained several components of the dystrophin-associated protein complex, including beta-dystroglycan and syntrophin. To better understand the potential function of Dp71Delta(110), collagen adhesion assays were performed on platelets isolated from wild-type or Dp71-deficient (mdx(3cv)) mice. Adhesion to collagen in response to thrombin was significantly decreased in platelets isolated from mdx(3cv) mice, compared with wild-type platelets. Collectively, our results provide evidence that Dp71Delta(110) is a component of the platelet membrane cytoskeleton, is involved in cytoskeletal reorganization and/or signaling, and plays a role in thrombin-mediated platelet adhesion.
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PMID:Identification of Dp71 isoforms in the platelet membrane cytoskeleton. Potential role in thrombin-mediated platelet adhesion. 1237 Jan 93