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:3.6.1.3 (ATPase)
65,361 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytomegalovirus (CMV) infection of simian virus 40 (SV40)-immune mice inhibits priming of SV40-specific helper and cytotoxic T lymphocytes (CTL) in vivo (A. E. Campbell, J. S. Slater, and W. S. Futch, Virology 173:268-275, 1989; J. S. Slater, W. S. Futch, V. J. Cavanaugh and A. E. Campbell, Virology 185:132-139, 1991). We now demonstrate that murine CMV (MCMV) infection of SV40-transformed macrophages and fibroblasts prevents presentation of SV40 T antigen to SV40-specific CTL. MCMV-infected macrophages failed to stimulate SV40-immune CTL precursors in vitro. In addition, MCMV-infected, SV40-transformed macrophage and fibroblast target cells lost their susceptibility to lysis by major histocompatibility complex class I-restricted, SV40-specific CTL clones. MCMV infection did not alter the synthesis of SV40 T antigen in the target cells. MCMV early gene expression was required for inhibition of SV40 T-antigen presentation; immediate-early gene expression was insufficient for this effect. Early viral gene expression also resulted in significant reduction of H-2K and H-2D molecules on the surface of MCMV-infected fibroblasts. However, this reduction occurred independently from suppression of antigen presentation to CTL. The same target cells which were resistant to lysis by SV40 CTL were susceptible to lysis by MCMV-specific CTL. MCMV early gene products therefore interfere with the processing and/or presentation of SV40 T-antigen determinants to CTL independent of alterations in the major histocompatibility complex.
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PMID:An early event in murine cytomegalovirus replication inhibits presentation of cellular antigens to cytotoxic T lymphocytes. 131 14

Antigenic peptides bound to class I molecules of the major histocompatibility complex (MHC) are recognized by T-cell receptors during development of an antiviral immune response. T cells respond to peptides derived from cytoplasmic viral proteins as well as viral membrane proteins, indicating that a pathway exists for the transport of proteins or peptides from the cytosol into the compartment(s) where the MHC class I molecules assemble. To investigate this pathway, we have developed an in vitro assay for the transport of peptides into microsomal vesicles. This assay provides evidence for the transport of chemically synthesized peptides (13-21 amino acids) containing N-linked glycosylation acceptor sequences, which serve as glycosylation substrates. Their transport results in depletion of the pool of available dolichol high-mannose oligosaccharides in the lumen of the microsomal vesicles. We have observed transport of peptides derived from antigenic human immunodeficiency virus gag and influenza B nucleoprotein sequences, but transport of a third randomly selected peptide was not detected, suggesting specificity of the transport process. We were not able to demonstrate ATP dependence of this peptide transport process by using apyrase and an ATPase inhibitor. This result was unexpected in light of the recent identification of MHC-linked genes with homology to ATP-binding cassette transporters, which have been proposed to mediate peptide transport.
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PMID:Evidence for peptide transport across microsomal membranes. 157 Mar 12

Cell line IgSV195, derived from a pancreatic tumor that arose in an SV40 T-antigen transgenic mouse, retains certain morphological and physiological characteristics of pancreatic beta-cells throughout in vitro and in vivo passage. Insulin secretion is stimulated by exposure of these cells to fetal bovine serum and a combination of 3-isobutyl-1-methylxanthine and glutamine but not by concentrations of glucose in the physiological range. Insulin processing appears to be intact. Neither class I nor class II major histocompatibility complex (MHC) antigens are routinely expressed at the cell surface; however, MHC class I--but not class II--encoded gene products are detected after treatment with recombinant interferon-gamma (IFN-gamma) alone or in combination with tumor necrosis factor. Cytolysis of IgSV195 cells by SV40 T-antigen-specific H-2b-restricted lymphocytes is similarly dependent on IFN-gamma pretreatment. These results emphasize that SV40 T-antigen transgenic mice are likely sources of cell lines that retain their differentiated function in vitro. The IgSV195 cell line provides an accessible model in which to investigate the control of gene expression and function of pancreatic beta-cells.
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PMID:Functional pancreatic beta-cell line from SV40 T-antigen transgenic mouse. 250 59

The E3/19-kDa glycoprotein (E3/19K) coded by adenovirus type 2 (Ad2) is known to inhibit the cell-surface expression of major histocompatibility complex (MHC) class I antigens by binding to the MHC antigens intracellularly, and thus reduces recognition of antigens by MHC-restricted cytotoxic T lymphocytes (CTL). We have studied the effect of the E3/19K expression in SV40-infected monkey cells, TC-7/H-2Kb and TC-7/H-2Db expressing transfected H-2Kb and H-2Db antigens, respectively, on the cell-surface H-2 class I antigens and on lysis of the cells by SV40 large tumor (T)-antigen-specific H-2Kb- and H-2Db-restricted CTL clones. H-2Db antigen expression on TC-7/H-2Db cells was drastically reduced by infection with Ad2 but not with an E3/19K-negative SV40-Ad2 hybrid virus, Ad2+ND1, as early as 12 hr postinfection. However, H-2Kb antigen expression on Ad2-infected TC7/H-2Kb cells remained unaltered, even at 24 hr postinfection. Specific lysis of SV40-infected TC-7/H-2Db cells by H-2Db-restricted SV40 T-antigen-specific CTL clones, Y-1 and Y-3, was strongly reduced by coinfection of the target cells with Ad2 but not with Ad2+ND1. Lysis of SV40-infected TC-7/H-2Kb cells by a H-2Kb-restricted SV40 T-antigen-specific CTL clone Y-4 was also reduced significantly by Ad2 infection, but not Ad2+ND1. These results indicate that the E3/19K protein affects cell-surface expression of H-2Db antigen but not H-2Kb antigen.
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PMID:Differential effect of adenovirus 2 E3/19K glycoprotein on the expression of H-2Kb and H-2Db class I antigens and H-2Kb- and H-2Db-restricted SV40-specific CTL-mediated lysis. 297 Jan 52

Immunohistological analysis of experimental gingivitis in humans was carried out to provide a baseline for the study of immunoregulatory mechanisms in chronic inflammatory periodontal disease. Using a panel of monoclonal antibodies in an avidin biotin immunoperoxidase technique, T cell subsets were identified and the pattern of Class II major histocompatibility complex (MHC) antigens determined. Twenty third-year dental students took part in the study. Following the cessation of oral hygiene procedures, gingival biopsies were taken from each of five students at days 0, 4, 8 and 21 during the development of the inflammatory lesion. Each student had one biopsy which healed uneventfully. The T4:T8 ratio showed only slight variation over the time course of the lesion varying from 2.18:1 at day 0 to 2.48:1 at day 4. At all stages the T cells displayed both HLA-DR and HLA-DQ antigens, but less than 10% had detectable IL-2 receptors. The predominant macrophage population was acid phosphatase + ve, adenosine triphosphatase -ve, HLA-DR+ and HLA-DQ+ antigens suggesting an activated phagocytic population. During the development of the lesion, the number of intraepithelial Langerhans cells (T6+) increased but there appeared to be a discrepancy between HLA-DR and HLA-DQ expression on these cells. Similarly, the keratinocytes expressed HLA-DR but failed to express HLA-DQ at any stage. These results suggest that the developing gingival lesion is a well controlled lesion and follows a similar pattern to a controlled delayed type hypersensitivity (DTH) response.
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PMID:Immunohistological analysis of experimental gingivitis in humans. 328 Jan 78

Epidermal Langerhans cells exhibit many features of macrophages/monocytes. Both bear surface receptors for the Fc portion of immunoglobulin molecules and the C3b complement component. Both take up, process, and present antigens to reactive lymphocytes in an effective fashion, and they display on their cell surfaces the alloantigenic determinants encoded by the I region of the major histocompatibility complex. In view of these facts, we explored the extent to which cutaneous sites with unusual immunologic attributes might correspondingly have maldistributions or decreased surface densities of Langerhans cells. Common body sites such as the ear, back, and abdominal wall skin in hamsters, mice, and guinea pigs had regularly distributed ATPase-positive Langerhans cells in surface densities between 500 and 1,500 cells/mm2. In contrast, hamster cheek pouch epithelium had fewer than 200 Langerhans cells/mm2 and murine tail skin exhibited both a decreased density and an unusual gridlike distribution of the cells. Langerhans cells were never demonstrated in corneal epithelium. Perturbation of body wall skin with ultraviolet light and with dinitrofluorobenzene temporarily depleted the skin of ATPase-positive Langerhans cells. Heterotopic grafts of hamster cheek pouch and murine tail skin tended to accumulate Langerhans cells and to become more like body wall skin. The concordance of Langerhans cell aberrations and unusual immunologic features of corneal cheek pouches and tail skins suggests the possibility that intentional perturbations of surface Langerhans cells, as with UVL, might achieve unusual immunologic reactions within normal body wall skin.
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PMID:Natural and perturbed distributions of Langerhans cells: responses to ultraviolet light, heterotopic skin grafting, and dinitrofluorobenzene sensitization. 644 86

In this study, we have used a mouse monoclonal antibody to rat Ia (RT1-B or class II) antigens to demonstrate, by immunofluorescence on frozen sections, intensely Ia-positive dendritic cells in the interstitial connective tissues of every tissue we have examined (heart, liver, thyroid, pancreas, skin, kidney, ureter, and bladder) with the striking exception of brain. The characteristics of the interstitial dendritic cell found in heart were studied in detail, and this cell was shown to be negative for acid phosphatase, beta-glucuronidase, and ATPase activity, and certainly some and probably all of the cells were negative for nonspecific esterase activity. Experiments with colloidal carbon suggested that the cell was either poorly or not at all phagocytic. The cells were negative for surface immunoglobulin and the W3/13 antigen, but positive for the leukocyte common antigen and the SD (Class I) antigens of the major histocompatibility complex. The cell was shown to be of bone marrow origin, and either the cell itself, or more probably its precursor, was shown to be sensitive to irradiation and to cyclophosphamide. All strains tested--including the nude rat--had large numbers of interstitial dendritic cells. The widespread distribution, except in brain, of this cell, which resembles in every respect the dendritic cell described by Steinman et al. (4) in the spleen and lymph nodes of the mouse, is of interest, and the implications in this finding are discussed.
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PMID:Demonstration and characterization of Ia-positive dendritic cells in the interstitial connective tissues of rat heart and other tissues, but not brain. 694 85

Epidermal Langerhans cells resemble macrophages/monocytes in several remarkable ways: both bear surface receptors for the Fc portion of immunoglobulin molecules and for the C3b complement component. They take up, process and present antigen to reactive lymphocytes in an extremely effective fashion. They display on their cell surfaces the alloantigenic determinants encoded by genes of the I region of the major histocompatibility complex. Using ATPase activity, Langerhans cell surface densities are abnormal in 3 cutaneous sites which exhibit unique immunologic properties: markedly reduced numbers in hamster cheek pouch; reduced numbers and uneven distributions in murine tail skin; no Langerhans cells occur within corneal epithelium. As a functional expression of the absence of Langerhans cells from murine corneas, allografts prepared from corneal epithelium fail to sensitize recipients to Ia antigens encoded by I region genes of the donor. Corneal grafts disparate from their hosts at only I region loci are accepted for at least 45 days. The absence of Langerhans cells from cornea may account in part for its property as an immunologically privileged tissue. Subthreshold numbers of Langerhans cells in cheek pouch epithelium may contribute significantly to the observations that the hamster cheek pouch is an immunologically privileged site. We infer that skin deficient in Langerhans cells may be consequently deficient in alloantigenicity. Equally important, Langerhans cell-poor skin may be lacking in certain essential functions relating to the induction and expression of immune reactivity.
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PMID:Unusual numbers and distribution of Langerhans cells in skin with unique immunologic properties. 699 73

The multicatalytic and multisubunit proteasomal complexes have been implicated in the processing of antigens to peptides presented by class I major histocompatibility complex molecules. Two structural complexes of this proteinase, 20 S and 26 S proteasomes, have been isolated from cells. By analyzing in vivo assembly of the proteasomal complexes we show that the 20 S proteasomal complexes are irreversibly assembled via 15 S assembly intermediates containing unprocessed beta-type subunits. The 20 S proteasomes further associate reversibly with proteasome activators PA28 or pre-existing ATPase complexes to form 26 S proteasomal complexes. Our findings that not all of the 20 S proteasomal complexes are assembled into 26 S proteasomal complexes within cells and that all of PA28 and ATPase complexes are associated with 20 S proteasomes strongly suggest that all proteasomal complexes coexist within cells. We further demonstrate that 26 S proteasomal complexes are predominantly present in the cytoplasm and a significant portion of the 20 S proteasomal complexes is associated with the endoplasmic reticulum membrane. Taken together, our findings suggest that depending upon their associated regulatory components, 26 S and 20 S-PA28 proteasomal complexes serve different housekeeping functions within the cells, while they degrade antigens in a cooperative manner in antigen processing.
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PMID:In vivo assembly of the proteasomal complexes, implications for antigen processing. 749 35

A cDNA clone complementary to an interferon (IFN)-induced mRNA approximately 3 kb in length was identified and sequenced revealing homology with the endoplasmic reticular heat shock protein/ATPase gp96. Both IFN-alpha and -gamma transcriptionally upregulate expression of this gene. gp96 transcripts, protein, and ATPase activity are shown to be enhanced as a result of IFN treatment in two human cell lines and this effect requires de novo protein synthesis. gp96 molecules have recently been implicated in the presentation of endogenous antigens. A number of the key elements in this pathway, the transporter proteins, the major histocompatibility complex (MHC)-linked units of the proteasomes and the MHC class I molecules are known to be IFN inducible. Our results show that yet another molecule suggested to play an accessory role in the endogenous presentation pathway is IFN inducible. Further, our studies represent the first demonstration of modulation of expression of a heat shock protein by a cytokine and identify a new enzymatic activity upregulated in IFN-treated cells.
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PMID:The endoplasmic reticular heat shock protein gp96 is transcriptionally upregulated in interferon-treated cells. 752 74


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