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

It is reported here that most cytotoxic T lymphocytes (CTL), which recognize class I major histocompatibility complex (MHC) loci, express the T cell differentiation antigen T8. However, a minority of T8+ CTL clones was found to recognize class II MHC antigens. To test the hypothesis that T8 is involved only in T cell recognition of class I MHC antigens, we studied the role of T8 in the cytotoxic activity of class II MHC-specific CTL. Monoclonal antibodies specific for T8 blocked the activity of most class I MHC-specific CTL clones but did not affect the activity of class II MHC-specific CTL clones. Moreover, a mild trypsin treatment of the clones, which removed and T8 determinant, affected the activity of class I MHC but not that of class II MHC-specific CTL clones. These findings indicate that the class II-specific MHC CTL clones described here did not require T8 for their cytolytic activity. The activity of one T8+ class I MHC-specific (HLA-B27) CTL clone (HG-61) against the B cell line JY, which was used to raise this CTL clone, was not blocked by trypsin treatment of this clone. However, the activity of CTL clone HG-61 against target cells different from JY but carrying the appropriate HLA specificity was blocked by anti-T8 antibodies and trypsin treatment. The implications of these findings for the hypothesis that T8 is involved only in the activity of CTL with a relatively low avidity for class I MHC antigens are discussed.
 ...
PMID:The role of T8 in the cytotoxic activity of cloned cytotoxic T lymphocyte lines specific for class II and class I major histocompatibility complex antigens. 257 37

Anti-lymphocytic antibodies (ALA) have been described in a variety of autoimmune disorders. We have investigated the presence of ALA in autoimmune chronic active hepatitis (aCAH) starting in childhood. Using a modified Terasaki technique ALA were found in 17 of 18 patients with aCAH but in only one of 15 patients with alpha-1-anti-trypsin deficiency or Wilson's disease and three of 27 age-matched healthy controls (P less than 0.0005 for both). Sera from 12 patients with uncontrolled aCAH had significantly higher cytotoxicity values than sera from six children with inactive diseases (P less than 0.01). ALA were directed to T but not B lymphocytes and were not reactive with specific HLA antigens. No preferential killing was observed against CD4 or CD8 positive T lymphocytes. Characterization of ALA revealed them to be cold-reactive IgM. The possible role of ALA in aCAH is discussed.
 ...
PMID:Anti-lymphocytic antibodies in autoimmune chronic active hepatitis starting in childhood. 278 29

In this work the reactivity of 16 monoclonal antibodies raised against different HLA class I specificities was tested with human skin of healthy donors of known HLA typing. By indirect immunofluorescence, six antibodies reacted strongly with keratinocytes carrying the corresponding alloantigens. The reactivity of 3 other antibodies which was weak or absent using indirect immunofluorescence, was enhanced by various amplification systems such as avidin-biotin-peroxidase method, biotin-streptavidin-fluorescein complex and especially preliminary trypsin treatment that revealed alloantigens masked in the epidermis. The immunostaining of 4 antibodies was negative regardless of the method used. Some of the antibodies we tested cross-reacted with cytoplasmic antigens of keratinocytes. This study has allowed to select a battery of monoclonal antibodies which can specifically detect alloantigens on keratinocytes and will be useful for the recognition the cell origin in allografting experiments.
 ...
PMID:Reactivity of anti-HLA class I polymorphic monoclonal antibodies with normal human skin. 331 66

Human and rabbit antibodies to trophoblast-lymphocyte cross-reactive (TLX) antigens were employed in an enzyme-linked immunosorbent assay (ELISA) to identify and characterize the TLX alloantigen system on human platelets. Neither washing nor extraction in chaotrope or acid altered platelet TLX. The antigen was significantly changed by pronase and trypsin digestion, but Folch extraction yielded antigen in the hydrophilic interface, suggesting carbohydrate. Rabbit antibodies prepared to HLA-negative human syncytiotrophoblast TLX antigens were shown by platelet ELISA to have the same specificity and similar allotypy as anti-TLX antibodies from secondary (2 degrees) spontaneously aborting women. Patients with normal pregnancies before becoming 2 degrees aborters had both IgG and IgM antibodies to TLX. Anti-TLX in patients who never had a normal pregnancy were predominantly IgG. ELISA reactions performed with different concentrations of protein in the buffers detected anti-TLX activity in buffers containing high protein concentrations. This has been observed in studies of blocking antibodies in graft-versus-host disease and immune responses to tumor cells. Platelet TLX offers a new genetic and immunological approach to study similarities of the host-parasite relationships in pregnancy, transplantation, and cancer.
 ...
PMID:Antigens of human trophoblast: trophoblast-lymphocyte cross-reactive antigens on platelets. 367 62

Epidermis from patients suffering from recurrent herpes labialis was separated from dermis by means of a suction blister device and dissociated with trypsin. The epidermal cell suspensions obtained were 80--95% viable and contained 3--5% Langerhans' cells, as judged by immunofluorescence staining of the cells with a rabbit anti-DR antiserum. T lymphocytes from the same patients were co-cultured with herpes simplex virus antigen (HSV-Ag) or live virus (HSV), with or without epidermal cells or macrophages. A strong proliferative T cell response to HSV-Ag and HSV was obtained, provided that the cultures also contained epidermal cells or macrophages. Pretreatment of the epidermal cells with a rabbit anti-DR antiserum plus complement abolished the responses, while pretreatment with normal rabbit serum plus complement did not. These data therefore indicate that HLA--DR positive Langerhans' cells are able to present herpes simplex virus in an immunogenic way to T lymphocytes.
 ...
PMID:Studies on human epidermal Langerhans' cells: II. Activation of human T lymphocytes to herpes simplex virus. 616 7

Monoclonal antibody BBM.1 (Brodsky, F.M., Bodmer, W. F., and Parham, P. (1979) Eur. J. Immunol. 9, 536-545) identifies an antigenic determinant of human beta 2-microglobulin (beta 2-M). The antibody binds free and HLA-A,B-associated beta 2-M with similar affinity, showing that the BBM.1 antigenic determinant does not involve residues of beta 2-M that interact with HLA-A,B heavy chains. Peptides (SWH.1-5) synthesized from residues 35-50 of the beta 2-M sequence specifically inhibit the binding of BBM.1 to cell surfaces. Their inhibitory activity is destroyed by trypsin treatment. The observations (i) that BBM.1 does not bind to beta 2-M of species other than man, gorilla, and chimpanzee and (ii) that arginine 45 is the only human-specific residue between positions 35 and 50 suggested that this residue might be part of the BBM.1 antigenic determinant. This hypothesis was confirmed by reversible modification of arginine residues with cyclohexanedione. Modification of arginines in native beta 2-M and of the single arginine, corresponding to position 45, in the peptide SWH.5 resulted in up to 95% loss of BBM.1 inhibitory activity. Reversal of the modification by treatment with hydroxylamine resulted in complete recovery of activity. Rabbit antibodies elicited by immunization of SWH.5 conjugated to bovine serum albumin showed no detectable reaction with native beta 2-M but did specifically react with human beta 2-M after sodium dodecyl sulfate-polyacrylamide gel electrophoresis and electrophoresis onto nitrocellulose. These results thus identify a region around residue 45 of the beta 2-M polypeptide which is exposed to the environment and not involved in binding HLA-A,B heavy chain. Analysis of the beta 2-M sequence by calculating local hydrophilicity indices (Hopp, T. P., and Woods, K. R. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 3824-3828) agree with this region being a major antigenic determinant. Models of beta 2-M structure as an immunoglobulin domain show this region of polypeptide to be part of a loop between the two layers of beta-pleated sheet, also consistent with it being a major antigenic determinant. The position of the loop favors a model in which beta 2-M interacts with HLA across the four-stranded beta-pleated sheet like an immunoglobulin constant region domain.
 ...
PMID:Arginine 45 is a major part of the antigenic determinant of human beta 2-microglobulin recognized by mouse monoclonal antibody BBM.1. 618 21

Human Langerhans cells (LC) are located in the epidermal tissue which is naturally accessible to UV irradiation. They may be the first immunocompetent cells exposed to its effect. In the present study, the epidermal tissue was dissociated with trypsin, and epidermal cell (EC) suspensions, which contain keratinocytes, melanocytes, and LC were irradiated with UVB (10 or 20 mJ/cm2). After irradiation LC retained their surface determinants: T-6 and HLA-Dr. In addition, their number did not decrease during 3 days of culture following UVB exposure as compared with nonirradiated EC cultured in parallel. On the contrary, UV irradiation of EC resulted in decreased lymphocyte-stimulating ability in a mixed skin cell-lymphocyte culture reaction (MSLR). EC used directly after irradiation in MSLR induced about half the lymphocyte response compared to nonirradiated EC. After 24-h culture, the irradiated EC did not produce any lymphocyte response, whereas the 48-h cultures showed a slight lymphocyte stimulation. At 72 h the cultures from irradiated and nonirradiated EC showed similar responses in MSLR. The doses of UV radiation which decreased MSLR responses did not affect EC viability and did not significantly reduce their DNA content. It is suggested that under the experimental conditions used in this study the defect induced by UV irradiation was essentially functional and was the result of the transient inhibition of the antigen processing function of LC rather than of an alteration in membrane antigen expression (T-6 and HLA-Dr).
 ...
PMID:In vitro effect of UV radiation on immune function and membrane markers of human Langerhans cells. 620 89

Human placental cell suspensions prepared by trypsin digestion were analyzed with several monoclonal antibodies on a multiparameter fluorescence-activated cell sorter (FACS). Five distinct cell populations were isolated on the basis of size and quantitative differences in the coordinate expression of cell surface antigens detected by monoclonal antibodies against an HLA-A,B,C monomorphic determinant (MB40.5) and against human trophoblasts (anti-Trop-2). By FACS analysis and after sorting we clearly identified the major cell population as cytotrophoblasts based on several independent criteria, including presence of trophoblast-specific surface antigens, Trop-1, and Trop-2; absence of all HLA class I, class II, and beta 2-microglobulin (beta 2m) antigens; absence of the pan-leucocyte and monocyte antigens, HLe1 and LeuM1, respectively; presence of Y-chromatin in a male placenta; presence of placental and not liver alkaline phosphatase; and a large, mononuclear morphology. These procedures provide a reproducible method for obtaining highly purified human cytotrophoblast populations for further studies. We measured by molecular hybridization (RNA or Northern blots) the HLA-A,B,C and beta 2m mRNA in total RNA extracted from sorted cytotrophoblasts. We find that normal human cytotrophoblasts have extremely small amounts of HLA-A,B,C mRNA: approximately 300 times less than that in the lymphoid cell line LCL-721 or normal lymphocytes. In contrast, they have approximately 11% the level of beta 2m mRNA present in LCL-721 cells. Thus, HLA-A,B,C antigen expression on human cytotrophoblasts is limited by the level of HLA heavy chain mRNA.
 ...
PMID:Transcriptional control of HLA-A,B,C antigen in human placental cytotrophoblast isolated using trophoblast- and HLA-specific monoclonal antibodies and the fluorescence-activated cell sorter. 620 84

Neuraminidase (Vibrio cholerae) treatment of human metastatic mammary carcinoma MDA-MB-231 cells grown in culture released 0.60-0.63 mg of N-acetylneuraminic acid from 10(9) cells. Incubation of intact cells with a modified trypsin and fractionation by gel filtration gave mainly O-glycopeptides. The presence of O-glycosyl-linked chains having one or two carbohydrate residues was confirmed by treatment of the glycopeptide fractions with galactose oxidase, followed by reduction with alkaline sodium borotritide and fractionation. The major glycopeptide fraction, which consisted of 53% carbohydrate and 47% protein, and a minor glycopeptide fraction each inhibited hemagglutination by peanut lectin. These results suggest the presence of O-beta-D-galactopyranosyl-(1 leads to 3)-O-(2-acetamido-2-deoxy-alpha-D-galactopyranosyl)-(1 leads to 3)-L-serine (threonine) residues. The absorptive capacities for anti-HLA-A2 and anti-HLA-B8 antisera were slightly greater for intact than for lyophilized cells, which suggested that masking of these major histocompatibility antigens did not occur in intact cells.
 ...
PMID:Isolation and partial characterization of surface components of cell line MDA-MB-231 derived from a human metastatic breast carcinoma. 628 76

Peripheral blood derived macrophages from lepromatous leprosy patients were unable to interact with lymphocytes in the presence of M. leprae. This lack of interaction is probably not associated with membrane HLA-Dr antigens since trypsin and colchicine restored M. leprae induced depression in the latter but were unable to bring about a positive interaction. Two possible defects exist therefore in the lepromatous macrophage. These are an innate inability to process and present M. leprae antigens to lymphocytes and an induced inability to express some membrane receptors, an event detrimental to the normal functioning of a macrophage.
 ...
PMID:Antigen specific macrophage-lymphocyte interaction in lepromatous leprosy. 637 10


<< Previous 1 2 3 4 5 Next >>