Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anti-epidermal cell sera (AES) were obtained by immunizing rabbits with enzymatically dispersed, viable guinea-pig epidermal cells followed by absorption with guinea-pig red blood cells, spleen and thymus cells, and liver powders. Complement-mediated cytotoxicity and immunofluorescence demonstrated that AES were towards cell surface antigen specific for stratified squamous epithelia of guinea pigs, and cross reacted with the corresponding tissues of humans and monkeys. Immunofluorescence revealed that AES reacted with Hassall's corpuscles and surrounding epithelial cells of the guinea-pig thympus which seemed to share common antigens with the epidermis; AES gave no reaction with other organs. While antigens reactive with pemphigus antibodies (PA) were demonstrated by membrane immunofluorescence to be present on the epidermal cell surface, PA showed no cytotoxicity to guinea-pig and human epidermal cells. Re-treatment of isolated epidermal cells with trypsin showed that antigens ractive with PA were more susceptible to the enzyme than those reactive with AES. These findings suggest that the cell surface antigens binding AES are different from the antigens which bind PA.
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PMID:Experimental production of rabbit anti-guinea-pig epidermal cell sera. Comparison to pemphigus antibodies. 6 55

This paper describes a new Mab BC-1 which is directed at a cell surface antigen expressed by extravillous cytotrophoblast and not by villous cytotrophoblast, so it is useful for distinguishing between the two populations. The antigen recognised by BC-1 is trypsin-resistant, which allows it to be used for flow cytometric analysis of living trophoblast isolated by enzymic disaggregation. However, BC-1 is not trophoblast-specific but cross-reacts with some other tissues, in particular endothelial cells and peripheral blood monocytes. The nature of this antigen has not been established.
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PMID:Evaluation of a monoclonal antibody, BC-1, which identifies an antigen expressed on the surface membrane of human extravillous trophoblast. 161 Apr 92

Expression of bovine coronavirus (BCV) antigen in the plasmalemma of epithelioid human rectal tumor (HRT-18) and fibroblastic bovine fetal spleen (BFS) cell lines was traced by immunofluorescence and immunoelectron microscopy facilitated by colloidal gold. Cytoplasmic fluorescence was first observed at 12 hr postinfection (h.p.i) in infected HRT-18 cultures. This fluorescence coincided with the appearance of cell surface antigen reacting with colloidal gold-labeled antibodies to BCV antigens. At 24 h.p.i the amount of viral antigens at the surface of HRT-18 had increased, although cytoplasmic fluorescence remained constant. Infected BFS cells but not HRT-18 cells formed polykaryons when incubated in the presence of trypsin. One viral antigen in the plasma membrane of BFS cells was thus identified as the S glycoprotein with a fusion domain. In contrast to HRT-18 cells, the overall amount of BCV antigens at the surface of BFS cells remained constant after the onset of fusion. Analysis of the labeling characteristics established that the gold-marked-sites represented de novo expression of BCV antigen in the plasma membrane of infected cells.
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PMID:Bovine coronavirus antigen in the host cell plasmalemma. 226 45

Previous studies have demonstrated that monoclonal antibody TFS-4 recognizes a cell surface antigen with a molecular weight of 124,000 expressed selectively on small-cell lung cancer but not on non-small-cell lung cancers and that it cross-reacts with human brain. The antigenic determinant on small-cell lung cancer and that on brain shared common characteristics, i.e., trypsin sensitivity, heat lability, and neuraminidase resistance, suggesting that they are similar peptides (T. Okabe et al., Cancer Res., 44: 5273-5278, 1984; J-i. Watanabe et al., Cancer Res., 47:826-829, 1987). In order to elucidate the nature of this unique antigen recognized by TFS-4, we have purified the antigen to homogeneity from human brain. The antigen was solubilized from brain with 0.5% Nonidet P-40, precipitated with 50% ammonium sulfate, and subsequently purified by sequential chromatographies, i.e., diethylaminoethyl-Sepharose ion exchange, immunoaffinity, and gel permeation high-pressure liquid chromatography. The antigenic reactivity was assessed by immunoblotting using TFS-4 as a primary antibody. The purified antigen showed a single protein band with a molecular weight of 124,000 on sodium dodecylsulfate-polyacrylamide gel electrophoresis detected by a silver staining technique. The results suggest that the antigen on brain tissues is structurally related to the molecule expressed on small-cell lung cancer.
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PMID:Isolation of small cell lung cancer-associated antigen from human brain. 243 35

In this study a double immunohistochemical staining procedure is described for the simultaneous demonstration of antigen expressing cells and replicating cells in rat thymus. As markers for cell surface antigen expression a monoclonal antibody against Ia-expressing cells (His 19) and a monoclonal antibody against cells of the monocyte-macrophage lineage (ED2) were used. Replicating cells were demonstrated by the incorporation of 5-bromodeoxyuridine (BrdUrd). Tissue pieces were fixed in a periodate-lysine-paraformaldehyde fixative and embedded in glycol methacrylate. To demonstrate Ia-expressing cells or ED2-positive macrophages in plastic embedded sections a digestion with trypsin is necessary. The staining procedure was applied sequentially and was performed with a peroxidase and an alkaline phosphatase labeled reagent yielding respectively a brown and a blue reaction product. Results with this staining procedure on plastic embedded sections of rat thymus, an organ with a high DNA synthesizing capacity, showed incorporation of BrdUrd predominantly in the cortex. ED2-positive macrophages were only found in the cortex. The Ia-positive epithelial reticular cells demonstrated extremely well their stellate form.
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PMID:Simultaneous immunohistochemical demonstration of antigen expression and 5-bromodeoxyuridine incorporation in plastic embedded sections. 243 84

We have produced a monoclonal antibody (SF-25) against a human hepatoma cell line (FOCUS) that strongly reacts with an antigen shared by all six colon adenocarcinoma cell lines. This cell surface antigen was uniformly expressed in all 17 human adenocarcinomas of the colon obtained at surgery but not on the normal adjacent mucosa counterpart. Other normal tissues were negative except for a population of cells in the distal tubule of the kidney as shown by immunoperoxidase staining and direct binding to membrane preparations. Binding of this Mr 125,000 antigen to antibody is disrupted by detergents, sodium dodecyl sulfate, and paraformaldehyde fixation but not by treatment of FOCUS cells with trypsin. The SF-25 antibody when labeled with 125I shows a striking capacity by both biodistribution and nuclear imaging studies to localize human colon adenocarcinoma grown as solid tumors in nude mice. SF-25 may be useful in distinguishing between normal colon and the transformed phenotype.
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PMID:In vivo localization of human colon adenocarcinoma by monoclonal antibody binding to a highly expressed cell surface antigen. 246 Feb 25

The biosynthesis and the maturation of Thy-1 antigen of mouse thymocytes have been studied by using a xenogeneic rabbit anti-mouse Thy-1 antibody. The earliest form of Thy-1 detected after a 5-min pulse with [35S]methionine and [35S]cysteine had an apparent m.w. of 26,500. During chase, this band converted to a molecular ratio (Mr) = 25,000 polypeptide, probably derived from the latter by trimming of glucose or mannose residues from the three high-mannose glycan units of Thy-1. Mature Thy-1 molecules were detected at the cell surface after a 15-min chase. At least one of the three N-linked oligosaccharide units was shown to be in the high mannose form at the cell surface, as indicated by its susceptibility to endo-beta-N-acetylglucosaminidase H digestion. Treatment of the early and late forms of Thy-1 antigen with endo-beta-N-acetylglucosaminidase F generated a single polypeptide of Mr = 13,500. The same precursor was obtained when cells were labeled in the presence of tunicamycin. This indicates the absence of O-linked glycan in the mature cell surface antigen. Finally, the resistance of Thy-1 antigen to trypsin digestion when associated with membranes confirmed that this molecule has no cytoplasmically oriented portion.
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PMID:Biosynthesis of mouse Thy-1 antigen. 285 27

When tumor cells develop in healthy adults, they activate the cellular immune system--natural killer (NK) cells, antigen-specific cytotoxic lymphocytes (CTL), and the synthesis of antigen specific cytotoxic antibodies. These are aimed at killing the intruding cells. However, in cancer patients the tumor continues to grow. As tumor cells proliferate, they were shown to release factors that mediate the inactivation of the host immune defense systems. The study documented in this article examined peripheral blood lymphocytes, mononuclear cells (MNC), NK cells, T-helper cells (THC). This study confirmed the interaction of the released inhibitor factors with these mononuclear cells. NULL cells from healthy adults responding to interleukin-2 (IL-2) and NILL cells from patients with metastatic breast carcinoma nonresponsive to IL-2 were also isolated by the standard antibodies-pinning technique. The cells were obtained from age-matched subjects: ten healthy adults; ten patients each from Stage I, II, III, and IV metastatic breast carcinoma (BCa-I, BCa-II, BCa-III, and BCa-IV or MBCa); and ten patients with benign breast disease (BBD). The responsiveness of these THC, PBMNC, NK, NULL, and NILL cells in vitro to graded levels of phytohemagglutinin (PHA), Concanavalin A (Con A), and recombinant interleukin-2 (rIL-2) was examined. Responsiveness was monitored by 3H-thymidine (3H-TdR) uptake, production and release of IL-2, interleukin-2 receptor (IL-2R), and cytotoxic activities against K-562 cells and breast carcinoma short-term cell lines. A lack of functional IL-2R in peripheral blood lymphocytes from patients with metastatic breast carcinoma was confirmed by nonsignificant anti-Tac antibody binding. An elevation in the expression of cell surface antigen GP-120 has been observed to be associated with the activation in vitro of T-cells from healthy adults and from patients with benign breast disease, but not of T-cells from patients with breast carcinoma. Biochemical studies of the GP-120 using high performance liquid chromatography combined with nitrocellulose blotting confirmed that the glycoprotein was resistant to trypsin and chymotrypsin, but susceptible to pronase. It contained sialic acid and lactosaminoglycan as O-linked sugars. It could be labeled with pariodate/NaB(3H4) and is recognized by MAbT-305 monoclonal antibodies. It contained sialic acid linked (2---3) to galactose.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Peripheral blood lymphocytes from patients with cancer lack interleukin-2 receptors. 296 32

A cell surface antigen (gp140) was previously shown to exist on T cell subsets as well as on monocytes and macrophages in normal peripheral blood. Elevated expression of this antigen was associated with immune system disorders, acute lymphocytic leukemias, and in vitro activation of T cells. The antigen could be identified with monoclonal antibody (MAb) T305. Gp140 was a biosynthetic product of T cells because it could be labeled with [3H]leucine or [3H] glucosamine. Biochemical studies of gp140 used high performance liquid chromatography with nitrocellulose blotting to isolate aliquots suitable for 125I radiolabeling and immunoprecipitation to demonstrate: a) a reduction in m.w. of gp140 KD to 90 KD after deglycosylation by trifluoromethanesulfonic acid, b) alteration of isoelectric point from 4.1 to 5.7 after neuraminidase treatments, c) absence of N-linked sugars based on resistance to endoglycosidase F, d) resistance to trypsin and chymotrypsin digestion but susceptibility to pronase, and e) presence of sialic acid and lactosaminoglycan as O-linked sugars. Gp140 could be labeled with the periodate/NaB[3H]4 technique, indicating its similarity to a class of sialoglycoproteins previously described on activated T-cells in mouse and man. The antigenic epitope recognized by MAb T305 contains sialic acid linked (2----3) to galactose; however, periodate oxidation of the exocyclic ring of sialic acid did not affect binding by MAb T305. In an attempt to determine the functional role of gp140, we tested the ability of MAb T305 to block: a) proliferation of peripheral blood lymphocytes to mitogens, b) response to interleukin 2 (IL 2) of an IL 2 dependent T cell line, and c) growth of a T-ALL derived cell line. No inhibition of proliferation or growth was noted. Although the function of gp140 remains unknown, its association with lymphocyte activation and certain disease states suggests that it may provide a target for modulation of the immune response. These studies characterize the structural features of gp140 and further define the epitope recognized by MAb T305.
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PMID:Characterization of a membrane surface glycoprotein associated with T-cell activation. 298 44

A cell type-specific monoclonal antibody (Mab) against a cell surface antigen of rat anterior pituitary somatotrophs has been generated by fusion of a nonsecreting mouse myeloma line with spleen cells from a mouse immunized with enzymatically dispersed anterior pituitary cells of adult random cycling female rats. Hybridomas were initially screened for antibodies to cell surface antigens by an enzyme-linked immunosorbant assay using rat anterior pituitary cells and smooth muscle cells of aorta as positive and negative controls, respectively. Positive clones were further checked for cell type specificity by immunofluorescence. Mab WHC-1 is an immunoglobulin M (IgM) with kappa-light chains and is cytotoxic in the presence of complement. Based on double immunofluorescence, this Mab reacted with 22.5 +/- 2.0% (+/- SEM) of the anterior pituitary cells of adult random cycling female rats. Among them, about 93.5 +/- 1.4% were somatotrophs, and only 4.1 +/- 1.2% were mammotrophs. Approximately two thirds of the somatotrophs were Mab WHC-1-positive. The reaction of this Mab with gonadotrophs, thyrotrophs, or corticotrophs were negligible. The percentage of Mab WHC-1-positive cells derived from immunoperoxidase staining was significantly greater than that from immunofluorescence. The cell surface antigen defined by Mab WHC-1 is expressed heavily on GH3 cells, but not on smooth muscle cells. It is resistant to trypsin digestion, but sensitive to ethanol treatment, and exhibits the solubility property of a glycolipid. Mab WHC-1 cross-reacts with the anterior pituitary cell of rabbits, but not mice. These results provide the immunological evidence for heterogeneity among somatotrophs and demonstrate the feasibility of making pituitary cell type-specific Mabs.
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PMID:Production and partial characterization of a monoclonal antibody to rat anterior pituitary somatotrophs. 327 36


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