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)

All intra J chain disulfide bridges of human sIgA, the disulfide bonds between the J chain and the two IgA monomers, and one inter IgA monomer disulfide bridge were determined. sIgA was isolated from colostrum of healthy women and digested with IgA1-specific protease followed by cyanogen bromide cleavage. This procedure generated fragments of 140 kDa, 60 kDa, and 28 kDa. The 28-kDa polypeptide comprised the complete J chain covalently bound to two alpha 1 chain octapeptides derived from the C-termini of two alpha 1 chains. The 28-kDa fragment was digested with trypsin. The resulting peptides were purified by RP-HPLC, and subsequently characterized by amino-acid analysis, mass spectrometry, and gas phase sequencing. These data unequivocally show that the J chain cysteines C1-C6, C4-C5, and C7-C8 form intra chain disulfide bridges. The second (C2) and the third (C3) J chain cysteines are disulfide linked to two alpha chain cysteines (C17) joining the two IgA monomers of sIgA tail to tail. The remaining two alpha chains of the two monomers are directly bound to each other via their ultimate cysteines (C17-C17). A new model for the J chain in sIgA is presented.
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PMID:Intra- and interchain disulfide bridges of the human J chain in secretory immunoglobulin A. 129 12

The specificity and properties of a novel IgA receptor expressed on the surface of a tissue culture-adapted B cell lymphoma, T560, that originated in murine gut-associated lymphoid tissue, have been explored. Like the IgA receptors of murine T and splenic B cells studied by others, the T560 IgA receptor is trypsin sensitive and neuraminidase resistant and is up-regulated on T560 cells by exposing them overnight to high concentrations of polymeric IgA. Unlike them, the T560 IgA receptor is inhibited by low concentrations of IgM and high concentrations of IgG2a and IgG2b, binds at pH 4.0 but not at pH 8.0, is down-regulated by activation of protein kinase C and is sensitive to phosphatidylinositol-specific phospholipase C, indicating that it is glycosyl phosphatidylinositol-linked to the cell membrane. It is not a cell-bound form of galactosyl transferase, does not appear to bind to Ig through carbohydrate residues and does not react specifically with antibody to secretory component. It may be a completely new, cross-reactive receptor, perhaps related in some way to the polymeric Ig receptor or to the receptor for IgA expressed on the apical surface of Peyer's patch M cells, which is known to cross-react with IgG. Alternatively, it may be homologous to the highly IgA-specific Fc alpha R of T cells but, perhaps because of its glycosyl phosphatidylinositol linker, may have an ability to move and interact with other Ig receptors on the cell surface such that Ig bound to them are cross-inhibitory.
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PMID:A novel IgA receptor expressed on a murine B cell lymphoma. 137 46

A GALT-derived B lymphoma, T560, that bears IgAR is described. T560 is IgG2a kappa +, Ia+, B220+, J11d+, Thy-1-, CD3-, CD4-, CD5-, Mac 1-, Mac 2-, nonspecific esterase negative and binds bromelain-treated mouse RBC but not SRBC or ORBC. It presents antigen, secretes IL-1, IL-4 and IL-6 but not IL-2, IL-5 or TGF beta and appears to be related to the Lyt 1+(CD5) lineage of B cells though it lacks Lyt 1. T560 bears IgAR that, on the cell surface, are completely cross-inhibited by low concentrations of IgM and by high concentrations of IgG2a and IgG2b. They do not appear to represent a cell-surface form of galactosyl transferase. They are inducible by high concentrations of IgA, sensitive to trypsin and insensitive to neuraminidase. They are down-regulated by activation of PKC with PMA, but their recovery is not inhibited by cycloheximide, indicating that they are not degraded or shed. They may either lose their affinity for IgA or be internalized without degradation. Seventy percent of IgA receptor activity is lost when T560 is treated with PI-PLC; part of this loss of activity is due to activation of PKC and is inhibited by staurosporine, but approximately 30% of it is not protected by staurosporine indicating that some, or all, of the IgA receptor of T560 is connected to the cell membrane via a GPI linker. The T560 IgA receptor could be related to the poly-Ig or M cell receptor.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Sensitivity of receptors for IgA on T560, a murine B lymphoma, to phorbol myristate acetate and to phosphatidylinositol-specific phospholipase C. 165 5

Rotavirus (RV) infections in newborns differ from those in older infants; the majority of RV infections that occur in neonates are mild or asymptomatic. Generally, fewer than one-third of RV-infected neonates have diarrhea, although rates have reached 77% in some hospital nursery populations. Cases with severe diarrhea, necrotizing enterocolitis, bowel perforation, and death have been reported, but such cases are very rare. Infection usually occurs during the first week of life and generally invokes a mucosal antibody response without a concomitant serologic antibody response. Neonatal RV infections appear to incite an immune response that affords significant protection against severe RV-associated diarrhea, although not necessarily against a symptomatic RV infection later in life. Strains that cause neonatal infections differ from those that infect older infants; the outer-capsid protein VP4 is highly conserved in "nursery" RV strains, a property that probably plays a key role in their attenuated virulence. Immaturity of proteolytic enzymes in the neonatal gut and presence of secretory anti-RV IgA and trypsin inhibitors in breast milk are other factors that could account for the asymptomatic nature of RV infections in newborns. Natural "nursery" strains of RV are currently being evaluated as vaccine candidates.
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PMID:Neonatal rotavirus infections. 166 Jan 85

Giardia lamblia antigens which react with sera from children with G. lamblia infection were investigated by sodium-dodecyl polyacrylamide gel electrophoresis and immunoblotting. Serum IgG, IgM and IgA response to the antigens were immunochemically characterized. Serum antibodies from all giardiasis patients, but none of the controls, was found to react with a 57-kilodalton antigen. The 57 kDa antigen elicited IgG and IgA but not IgM antibodies. The protein nature of the 57 kDa antigen was demonstrated by loss of antibody recognition after trypsin treatment of G. lamblia trophozoites. Subcellular fractionation of G. lamblia trophozoites followed by SDS-PAGE and immunoblotting showed that the 57 kDa antigen was probably not a component of the cytoskeleton.
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PMID:Serum antibody response in children with Giardia lamblia infection and identification of an immunodominant 57-kilodalton antigen. 185 78

The Fc region of IgG of most mammals binds protein A on S. aureus resulting in high backgrounds when measuring specific antibodies to S. aureus in the ELISA. Removal of protein A from S. aureus or modification of the Ig Fc to prevent binding to protein A could affect specific antibody binding. We compared effects of blockage of Fc binding to protein A with purified protein A to trypsin removal of protein A from S. aureus, on specific antibody binding. When NMS was incubated without and with protein A (0 microgram, 50 micrograms, 200 micrograms and 400 micrograms) and high protein A Cowan I was the bound S. aureus antigen in the ELISA, absorbance OD405 was 0.769, 0.240, 0.224 and 0.210 +/- SE 0.026. When mouse Mab (IgG1, kappa) to bovine IgA was incubated without and with protein A (400 micrograms) prior to reaction with bovine IgA in the ELISA, absorbance was 0.645 and 0.639, indicating protein A had no effect on specific antibody binding. To determine the effect of trypsin on specific binding, Becker S. aureus was trypsin treated before linking it to microtiter wells. When Mab (IgM) to Becker (Nelles et al., Infect. Immun. (1985) 49, 14) was incubated with protein A (400 micrograms) before use in the ELISA, trypsin treatment of Becker resulted in reduced specific antibody activity (untreated Becker = 1.306, trypsin treated Becker = 0.331). These results suggest that purified protein A can be used to block nonspecific binding via Fc of Ig to S. aureus, thus avoiding trypsin denaturation of surface antigens.
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PMID:Prevention of nonspecific binding of immunoglobulin to Staphylococcus aureus protein A in ELISA assays. 194 Mar 86

The cause or causes of asthma among employees in aluminum smelters is unknown. We attempted to ascertain whether such workers who developed asthma differed in respect to indices of immunological function and certain genetic markers. Data were collected from 33 asthmatic and 127 nonasthmatic potroom workers. Asthmatic workers had significantly lower mean serum levels of immunoglobulin (Ig)M; however, mean levels of IgG and IgA, median levels of IgE, the capacity for recall of delayed type hypersensitivity, levels of immune complexes, and frequency of antinuclear or other autoantibodies did not differ from values for nonasthmatic workers. Asthma was found to develop on a background of atopy in 21 workers (64%), whereas there were no features of atopy in 12 workers (36%). Cigarette smoking had independent effects on immunological function. In respect to genetic markers, there was a higher frequency among asthmatic workers of the alpha-1-anti-trypsin deficiency phenotype MS, but the frequency of blood groups, Gm allotypes, or human leucocyte antigen types was similar. The study established that the profile of immune function, or genetic markers tested, did not differ essentially for workers in an aluminum smelter who did or did not develop asthma; however, there was an indication of heterogeneity in causation, as judged by "atopy-related" and "non-atopy-related" groups in the asthma population.
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PMID:An immunologic and genetic study of asthma in workers in an aluminum smelter. 226 22

To increase our understanding of the immune response to Anisakis infection, antigen specific IgG, IgA and IgE responses were identified using an immunoblot technique after polyacrylamide gel electrophoresis of excretory-secretory products from the larval stage of Anisakis simplex. Nine sera were drawn from proven cases of gastric anisakiasis within 3 days after symptoms had developed. The molecular weight of the major antigenic bands were distributed between 50 kDa and 120 kDa of the antigens. In nine cases of gastric anisakiasis, three of them were positive for IgG response, five for IgE, and six for IgA, respectively. None of control sera recognized the antigenic bands in IgA and IgE responses. In contrast, two controls had IgG antibodies against 1-2 proteins in the 65-95 kDa region. The antigenicity of the excretory-secretory products was lost following treatment by 0.2% trypsin, but not by 0.2 M periodic acid. Based on the results of reactivity to lectins, antigenic bands of the ES products possessed mucin type glycoconjugate residues in their protein portion. This indicates that the humoral responses of IgA and IgE antibodies to the larval ES antigens are a more reliable index of infection than that of the IgG response.
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PMID:Immunoblot analysis of serum IgG, IgA and IgE responses against larval excretory-secretory antigens of Anisakis simplex in patients with gastric anisakiasis. 228 72

Immunofluorescence staining in unfixed or fixed renal biopsy specimens were evaluated in nine patients with diabetic nephropathy in order to elucidate if immunofluorescence staining is applicable in fixed renal tissues in such patients. Renal biopsy specimens were embedded in gelatin or paraffin matrix. Renal biopsy specimens embedded in paraffin matrix were digested with 0.05% protease. Immunofluorescent studies of kidney tissues were performed by staining with FITC-labeled heavy chain specific anti-human IgG, IgA, IgM, acute phase reactant (APR) proteins such as alpha 1-anti-trypsin (alpha 1-AT), haptoglobin (Hpt) and beta-lipoprotein (beta-Lp) antisera, and then examined with a fluorescent microscope. Linear and nodular deposition of IgG, IgA, IgM, alpha 1-AT, Hpt, and beta-Lp were observed in the glomerular capillary walls of the renal specimens embedded in paraffin matrix. The staining patterns in specimens embedded in paraffin matrix was similar to that embedded in gelatin matrix. There was no significant difference in the intensity or distribution of IgG, IgM, alpha 1-AT, and beta-Lp deposition among the two different conditions of immunofluorescence in patients with diabetic nephropathy. It was suggested that immunofluorescence staining in renal biopsy specimens embedded in paraffin matrix after digestion with protease is useful for the evaluation of IgG, IgM, APR proteins, and beta-Lp in glomeruli from patients with diabetic nephropathy.
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PMID:Immunofluorescence staining in unfixed or fixed renal biopsy specimens from patients with diabetic nephropathy. 241 46

The aim of this report was to identify the region(s) of the secretory component (SC) molecule involved in in vitro binding to dimeric IgA. Inhibition of the SC binding was tested by Fab' antibody fragments directed against the accessible (A) and inaccessible (I) regions of SC. Antibodies directed against the main 38.5-kDa trypsin fragment of SC, and antibodies from two immune sera with a wide anti-SC spectrum, were also used. The specificity and activity of the five antibody preparations were established by double-diffusion in gel and by their SIgA combining capacity. Inhibition curves were established by RIA using constant amounts of 125I SC, dimeric IgA and increasing quantities of the various Fab' antibodies. These results indicated involvement of a larger part than the I region of the SC molecule in combination with dimeric IgA, perhaps including a second (minor?) site of binding on the accessible parts in addition to the major region located on I.
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PMID:Human secretory component. IV: Antigenic regions involved in in vitro binding to dimeric IgA. 242 39


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