Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

In the present study, we analyzed the mechanism by which human Langerhans cells (LC), the dendritic cells (DC) from epidermis, support the induction of a primary allogeneic T cell response. We reported that paraformaldehyde (PF) fixation completely abrogated the stimulatory property of freshly isolated LC, although the level of major histocompatibility complex (MHC) class II antigen (Ag) expression was unaltered by the fixative. Addition of either interleukin (IL)-1 beta and/or IL-6, during the mixed epidermal cell lymphocyte reaction, failed to restore the proliferative response. By contrast, when human LC were incubated for 3 days in culture medium before fixation, they retained a low but significant allostimulatory capacity. Trypsin treatment of incubated LC before fixation did not impair their function, suggesting that stimulatory activity by fixed incubated LC did not merely reflect a repair of LC membrane after trypsin trauma suffered during epidermal cell (EC) isolation. More interestingly, we found that addition of interferon-gamma during LC incubation mediated an enhanced allostimulatory activity by the PF-fixed LC. Acquisition of allostimulatory property by in vitro activated and fixed LC did not correlate with increased MHC class II Ag expression at the cell surface. By contrast, we showed that ICAM-1 Ag expression by human LC is involved in this maturation process. Finally, we found that once human LC have been activated, IL-1 beta, but not IL-6, could serve as a costimulatory factor in the primary allogeneic T cell response. In conclusion, the data suggest that human LC accessory function is not constitutive but requires an activation step which can be provided by interferon-gamma during LC-T cell interaction.
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PMID:Dissection of human Langerhans cells' allostimulatory function: the need for an activation step for full development of accessory function. 843 73

In the present study, in vitro attempts have been made to define the cytokine profile of CD4+ T cells from polar leprosy patients and healthy individuals against Mycobacterium leprae-derived heat shock proteins (HSPs), HSP65 and HSP18, and their trypsin-digested fragments, relating to HLA-DR polymorphism. While all tryptic fragments of optimal digestion and undigested HSPs could stimulate CD4+ T cells from tuberculoid (TT) leprosy patients and healthy contacts (stimulation index, SI > 2.0), only two fragments, TDB65-2 (18 kDa) and TDB18-3 (3 kDa) triggered CD4+ T cells of anergic lepromatous (LL) leprosy patients. Both of these HSPs and their tryptic fragments showed diverse HLA-DR restriction, with DR15 providing the strongest restriction. Cytokine analysis demonstrated that HSP65 and HSP18 induced Th1-like activity in the context of all the restricting HLA-DR alleles, except DR1 and DR7 which induced a Th2 type of response against HSP65 and HSP18, respectively. These Th2 inducer epitopes on HSP65 (DR1 restricted) and HSP18 (DR7 restricted) were absent from TDB65-2 and TDB18-3 which exclusively triggered Th1 cells in both TT and LL forms of leprosy in the context of multiple DR alleles, DR15 being the major antigen-presenting allele. These studies suggest that the major histocompatibility complex phenotype of the antigen-presenting cell can modulate Th1-like versus Th2-like activity against M. leprae pathogens in leprosy and healthy individuals.
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PMID:HLA-DR polymorphism modulates the cytokine profile of Mycobacterium leprae HSP-reactive CD4+ T cells. 900 43

The crystal structure of the 20S proteasome from the yeast Saccharomyces cerevisiae shows that its 28 protein subunits are arranged as an (alpha1...alpha7, beta1...beta7)2 complex in four stacked rings and occupy unique locations. The interior of the particle, which harbours the active sites, is only accessible by some very narrow side entrances. The beta-type subunits are synthesized as proproteins before being proteolytically processed for assembly into the particle. The proforms of three of the seven different beta-type subunits, beta1/PRE3, beta2/PUP1 and beta5/PRE2, are cleaved between the threonine at position 1 and the last glycine of the pro-sequence, with release of the active-site residue Thr 1. These three beta-type subunits have inhibitor-binding sites, indicating that PRE2 has a chymotrypsin-like and a trypsin-like activity and that PRE3 has peptidylglutamyl peptide hydrolytic specificity. Other beta-type subunits are processed to an intermediate form, indicating that an additional nonspecific endopeptidase activity may exist which is important for peptide hydrolysis and for the generation of ligands for class I molecules of the major histocompatibility complex.
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PMID:Structure of 20S proteasome from yeast at 2.4 A resolution. 908 96

Thymocytes with a CD4(hi)CD8(lo) coreceptor-skewed (CRS) phenotype have been shown to contain precursors for CD8 single-positive (SP) thymocytes, in addition to precursors for CD4 SP cells. The selection mechanisms that stimulate CD4(hi)CD8(lo) cells to revert to the CD8 lineage are not known. Mice transgenic (tg) for the major histocompatibility complex (MHC) class I-restricted P14 T cell receptor (TCR), on the H-2bm13 background, generate a large number of CD4(hi)CD8(lo) CRS thymocytes. We analyzed the developmental potential and the differentiation requirements of the CD4(hi)CD8(lo) population of these mice. Using reaggregate thymic organ cultures (RTOC), we observed that these cells efficiently and almost exclusively differentiate into CD8 SP cells. Differentiation occurred independent of whether or not the MHC haplotype of the thymic stroma corresponds to the MHC restriction of the tg TCR. Loss of CD4 was independent of thymic stroma, up-regulation of CD8 to full levels was dependent on thymic stroma but independent of MHC haplotype. After trypsin treatment and overnight incubation, these CRS cells re-expressed CD8 but failed to re-express CD4, indicating that they are in the process of terminating CD4 synthesis. CD8 SP cells derived from the CRS cells proliferate in response to peptide-pulsed antigen-presenting cells. Our data suggest that CD4(hi)CD8(lo) CRS thymocytes bearing the P14 tg TCR have completed positive selection and differentiate autonomously into functionally competent CD8 SP cells.
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PMID:Differentiation of CD4(high)CD8(low) coreceptor-skewed thymocytes into mature CD8 single-positive cells independent of MHC class I recognition. 929 41

C3H/HeJBir mice are a new substrain that spontaneously develop colitis early in life. This study was done to determine the T cell reactivity of C3H/HeJBir mice to candidate antigens that might be involved in their disease. C3H/HeJBir CD4+ T cells were strongly reactive to antigens of the enteric bacterial flora, but not to epithelial or food antigens. The stimulatory material in the enteric bacteria was trypsin sensitive and restricted by class II major histocompatibility complex molecules, but did not have the properties of a superantigen. The precursor frequency of interleuken (IL)-2-producing, bacterial-reactive CD4+ T cells in colitic mice was 1 out of 2,000 compared to 1 out of 20,000-25,000 in noncolitic control mice. These T cells produced predominately IL-2 and interferon gamma, consistent with a T helper type 1 cell response and were present at 3-4 wk, the age of onset of the colitis. Adoptive transfer of bacterial-antigen-activated CD4+ T cells from colitic C3H/HeJBir but not from control C3H/HeJ mice into C3H/HeSnJ scid/scid recipients induced colitis. These data represent a direct demonstration that T cells reactive with conventional antigens of the enteric bacterial flora can mediate chronic inflammatory bowel disease.
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PMID:CD4+ T cells reactive to enteric bacterial antigens in spontaneously colitic C3H/HeJBir mice: increased T helper cell type 1 response and ability to transfer disease. 950 Jul 88

Peptide carriers, such the homeodomain of Antennapedia molecule (AntpHD), which spontaneously cross cellular membranes, have been exploited to deliver antigenic peptide Cw3 to the major histocompatibility complex (MHC) class-I presentation pathway and to prime cytotoxic T cells (CTL). However, the in vivo use of AntpHD recombinant peptide has been limited because CTLs can only be primed in the presence of sodium dodecyl sulfate (SDS) as adjuvant. In this report, we have exploited liposomes to protect the AntpHD-Cw3 from serum degradation and to facilitate the delivery of the recombinant peptide into the MHC class-I pathway of antigen-presenting cells. We have demonstrated that AntpHD recombinant peptide spontaneously associates with liposomes and this association is stable in vitro. However, exchange studies assessing the transfer of the peptide to model membranes or cells in vitro indicates that approximately 50% of the liposome-associated peptide is readily exchangeable. This is consistent with trypsin-protection assays, which have shown that approximately 40% of the liposome-associated peptide is protected from hydrolysis. Importantly, macrophages and dendritic cells are able to internalize AntpHD recombinant peptide associated with liposomes resulting in efficient delivery of the CTL peptide into the cytosol. These studies have demonstrated that dendritic cells treated with AntpHD-Cw3 in liposomes sensitize CTL clones to lyse syngeneic target cells expressing Cw3 epitope. This strategy, which combines liposomes and a peptide vector, provides a new approach for introducing molecules into the MHC class-I antigen presentation pathway of dendritic cells.
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PMID:Characterization of hybrid CTL epitope delivery systems consisting of the Antennapedia homeodomain peptide vector formulated in liposomes. 1140 58

This study sought to explore the change of the major histocompatibility complex (MHC) antigen expression and the endothelization of blood vessel in minor pig after trypsin treatment, and to provide data for xenotransplantation and pig vessel for use in tissue engineering. Western blot assays were conducted for detecting the expression of MHC xenoantigens. Scanning electron microscopy was used for checking the endothelization of decellularized blood vessel. The results showed that MHC antigen is not expressed after trypsin treatment. The endothelization is accomplished. The endothelial cells have normal morphological distribution. These demonstrate that the antigen of pig aorta is significantly decreased and it can be used for constructing new vascular grafts.
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PMID:[Antigen expression and the endothelization of biologic blood vessel matrix]. 1502 62

Neuropathic pain involves co-regulation of many genes and their translational products in both peripheral and central nervous system. We used proteomics approaches to investigate expressional changes in cytosolic protein levels in rat brainstem tissues following ligation of lumbar 5 and 6 (L5, L6) spinal nerves, which generates a model of peripheral neuropathic pain (NP). Proteins from brainstem tissue homogenates of NP and SHAM animals were fractionated by two-dimensional (2-DE) gel electrophoresis to produce a high-resolution map of the brainstem soluble proteins. Proteins showing altered expression levels between NP and SHAM were selected. Isolated proteins were in-gel trypsin-digested and the resulting peptides were analyzed by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. Using the mass spectrometric data, we were able to identify 17 proteins of interest through searches of the Swiss-Prot and NCBi nonredundant protein sequence database. Several of the identified proteins, including fatty acid binding protein-brain (FABP-B), major histocompatibility complex (MHC) class 1, T-cell receptor (TCR) alpha chain, and interleukin-1 (IL-1), showed significantly higher levels in the NP rat brainstem. Proteomic analysis has identified several proteins with differential expression levels in NP as compared to SHAM. However, the function of the proteins identified is postulated; therefore, further experiments are required to determine the true role of each protein in NP.
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PMID:Proteomic identification of brainstem cytosolic proteins in a neuropathic pain model. 1536 94

Despite the obvious importance of limbal stem cells in corneal homeostasis and tumorigenesis, little is known about their specific biological characteristics. The purpose of this study was to characterize limbal slow-cycling cells based on the expression of ABCG2 and major histocompatibility complex (MHC) class II and the cell size. Wistar rats were daily injected with 5-bromo-2-deoxyuridine (BrdU) at a dose of 5 mg/100 g for 2 weeks. After 4-week BrdU-free period, corneal tissues were excised, and immunofluorescence staining for ABCG2, BrdU, and MHC class II was performed by confocal microscopy. In another series, corneal tissues of normal rat were double immunostained for ABCG2, keratin 14, keratin 3, CD11c, and MHC class II. In addition, limbal, peripheral and central corneal epithelial sheets were isolated by Dispase II digestion and dissociated into single cell by trypsin digestion and cytospin preparations were double immunostained for ABCG2 and MHC class II. The cell size and nucleus-to-cytoplasm (N/C) ratio of limbal ABCG2+ cells were analyzed and compared with those of cells from other zones. BrdU label-retaining cells (LRCs) with expression of ABCG2 were found in the limbal epithelial basal layer, but not in other parts of the cornea. Approximately 20% of these cells were MHC class II positive. All MHC class II+ cells in the corneal epithelium were positive for CD11c, a marker for dendritic cells (DCs). Double labeling with ABCG2 and keratin 14 showed that nearly four-fifth of limbal ABCG2+ cells were positive for keratin 14 but negative for keratin 3, exhibiting an undifferentiated epithelial cell lineage. Cytospin sample analysis revealed the presence of a distinct population of smaller ABCG2+ cells with expression of MHC class II with a larger N/C ratio in the limbal epithelium. A new population of small slow-cycling cells with large N/C ratio has been found to express ABCG2 in the limbal epithelial basal layer. Some of these cells normally express MHC class II antigen. These findings may have important implications for our understanding of the characteristics of limbal slow-cycling cells.
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PMID:Existence of small slow-cycling Langerhans cells in the limbal basal epithelium that express ABCG2. 1725 66

Staphylococcal enterotoxin B (SEB), a toxin produced by Staphylococcus aureus, causes food poisoning and other fatal diseases by inducing high levels of pro-inflammatory cytokines. These cytokines are released from CD4+ T cells and major histocompatibility complex (MHC) class II antigen-presenting cells, which are activated through binding of wild-type (WT) SEB to both the MHC class II molecule and specific T-cell receptor Vbeta chains. Here, we focused on a trypsin/cathepsin cleavage site of WT SEB, which is known to be cleaved in vivo between Lys97 and Lys98, located within the loop region. To know the function of the cleavage, an SEB mutant, in which both of these Lys residues have been changed to Ser, was examined. This mutant showed prolonged tolerance to protease cleavage at a different site between Thr107 and Asp108, and structural analyses revealed no major conformational differences between WT SEB and the mutant protein. However, differential scanning calorimetric analysis showed an increase in enthalpy upon thermal denaturation of the mutant protein, which correlated with the speed of cleavage between Thr107 and Asp108. The mutant protein also had slightly increased affinity for MHC. In the in vivo experiment, the SEB mutant showed lower proliferative response in peripheral blood mononuclear cells and had lower cytokine-induction activity, compared with WT SEB. These results highlight the importance of the flexible loop region for the functional, physical and chemical properties of WT SEB, thus providing insight into the nature of WT SEB that was unrevealed previously.
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PMID:Contribution of the flexible loop region to the function of staphylococcal enterotoxin B. 2018 57


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