PubMed Health⌕ Search

Biomedical subjects

G Pryce

Publications and source records attributed to G Pryce.

31 records · Page 2Linked to original sources
PubMed1988

Kinetics of MHC gene expression and mRNA synthesis in brain endothelium.

Rat brain endothelium was examined in vitro to determine the sequence of events in MHC gene activation following IFN-gamma stimulation. The cell-triggering time, kinetics of mRNA synthesis, rate of MHC induction and rate of decay were measured by quantifying cell-surface MHC expression in the presence or absence of alpha-amanitin. Enhanced class I expression is triggered immediately after IFN-gamma stimulation, and is maximally induced by 4 hr of stimulation. New class I mRNA synthesis starts immediately and proceeds over the next 24 hr. This is followed by increased expression of class I molecules, which reaches plateau levels by 24 hr. While IFN-gamma is present, enhanced class I expression is maintained at 140-200% of that seen on resting cells. On removal of IFN-gamma, class I expression decays towards the levels seen on resting cells, with a half-life of approximately 40 hr. Class II molecules can be induced on these cells as well, but it requires the continuous presence of higher levels of IFN-gamma for more than 48 hr to trigger the cells. Induced class II molecules start to appear 2 days after pulsing and continue to increase until Day 4. If the IFN-gamma is removed from the cultures, class II expression declines rapidly towards zero, with a half-life of approximately 30 hr.

Animals↗
PubMed1987

Serological evidence for a defect in RT1.B (I-A) expression by the BDIX rat strain.

Astrocytes, astrocytic cell lines and endothelium from BDIX rats were stimulated with recombinant interferon-gamma (IFN-gamma) and the expression of MHC molecules quantified using an enzyme immunoassay (EIA). Using the two mouse anti-RT1.B monoclonal antibodies MRC OX4 and OX6, previously described as recognizing a monomorphic determinant on RT1.B, as well as polyvalent rabbit anti-rat class II antisera, we were unable to demonstrate any induction of RT1.B molecules on these cells under conditions that induced RT1.B expression in all other strains tested. In contrast, RT1.D locus class II molecules, detectable by the antibody MRC OX17, are more strongly expressed in BDIX than in other strains. In experiments using BDIX lymphocytes, this serologically detected defect in RT.1B expression was confirmed using four additional mouse anti-mouse I-Ak monoclonal antibodies, which cross-reacted on all rat strains tested except BDIX. It appears likely that BDIX rats lack either a structural or controlling gene required for RT1.B expression.

Animals↗
PubMed1987

Antigen presentation in brain: MHC induction on brain endothelium and astrocytes compared.

Primary cultures of rat brain endothelium and astrocytes were cultured in vitro, stimulated with interferon-gamma (IFN gamma), and the levels of MHC expression were then measured by an enzyme immunoassay (EIA). Class I expression is enhanced on brain endothelium by Day 1 following stimulation, and attains a plateau level of expression. Class II is normally absent, but starts to appear at Day 2, and continues to increase until Day 5. Class II rat I-A homologue is induced much more strongly than I-E, and the dose-response curves show that I-A expression is dependent on interferon dose within the range 2-500 units/ml, whereas class I enhancement is uniform over this range. The endothelium was compared with astrocytes, in regard to MHC induction. The surface density of class I and class II molecules was lower on the astrocytes in all conditions, and both class I enhancement and class II induction were in some cases slower to appear than on endothelium treated similarly. We also describe a pre-astrocytic cell line, C9, which shows strong I-E expression when stimulated with IFN gamma, but is apparently unable to express I-A. The implications of these findings for the development of immune reactions in the brain are discussed.

Animals↗
PubMed1986

Characterization of monoclonal antibodies directed towards the microsomal/microvillar thyroid autoantigen recognized by Hashimoto autoantibodies.

Monoclonal antibodies reacting with thyroid microsomes have been described. In this report, we present evidence that some of these monoclonal antibodies (MoAb) MAH C3 and perhaps MAH C6 are directed towards the thyroid microsomal antigen towards which microsomal autoantibodies from Hashimoto patients are directed. Immunofluorescence on cryostat sections with MAH C3 and MAH C6 on thyroid gland gave cytoplasmic staining patterns that were comparable to those obtained with autoantibodies. By western blotting, reactivity of MAH C3 was shown to be directed towards a 105,000 mol. wt component, comparable to that recognized by autoantibodies by immunoprecipitation. Double immunofluorescence with MAH C3 and autoantibodies on cultured, viable thyroid monolayers revealed a large number of comparable binding sites; in contrast, binding sites for asioloagalactothyroglobulin were different of binding of MAH C3 by the autoantibodies suggesting that the epitopes recognized were different. This was confirmed with the use of a rat thyroid cell line FRTL-5 and fluorescence activated cell sorter analysis which showed binding to the rat microsomal component with autoantibodies but negligible binding with MAH C3 and MAH C6. It therefore appears that the monoclonal antibodies recognize species specific determinants while the autoantibodies recognize species cross reactive determinants. These monoclonal antibodies will be useful for purification and immunochemical analysis of this autoantigen in human thyroid disease.

Animals↗
PubMed1985

Structural features of the autoantigens involved in thyroid autoimmune disease: the thyroid microsomal/microvillar antigen.

The microsomal/microvillar antigen of the human thyroid gland which provokes thyroid autoimmunity was characterised by immunoprecipitation studies. Sera from patients with Hashimoto's thyroiditis, primary myxoedema or Graves' disease containing autoanti-microsomal antibody specifically precipitated a component, which under reducing conditions migrates with a mol. wt of 105,000 on SDS-polyacrylamide gel electrophoresis. This protein was absent in auto- or xeno-anti-thyroglobulin precipitates, which under reducing conditions display four polypeptides of Mr 260,000, 230,000, 180,000 and 142,000. Under non-reducing conditions, the microsomal/microvillar antigen displayed a small shift in mobility to a mol. wt of 117,000 suggesting the presence of intrachain disulphide bonds. In contrast, under these conditions, anti-thyroglobulin precipitated components displaying polypeptides of approx. mol. wts in the region of 240,000-260,000, 170,000-180,000 and 140,000. Absorption of thyroiditis sera on thyroglobulin-Sepharose followed by immunoprecipitation abolished the anti-thyroglobulin components without affecting the binding of the 105,000-dalton polypeptide, if the sera contained antimicrosomal antibody. No comparable material was identified in microsomal membrane preparations prepared from the stomach which is also commonly involved in organ-specific autoimmunity. The 105,000-dalton component does not bind to a Lens culinaris lectin affinity column. We conclude that the epitopes of the microsomal/microvillar antigen are presented on a poorly glycosylated peptide of mol. wt 105,000, which is probably stabilised by intrachain disulphide bonds and which does not share serological reactivity with membrane-bound thyroglobulin.

Antigens↗
PubMed1985

Molecular analysis of induced idiotypes associated with autoanti-thyroglobulin.

Idiotype (Id) and autoanti-thyroglobulin were induced in different strains of mice by priming with anti-Id to monoclonal anti-thyroglobulins (D8 and G4) and challenged with a subimmunogenic dose of thyroglobulin (Tg). Both D8.Id and G4.Id were induced in CBA mice by priming with the appropriate anti-Id, but only priming with anti-D8.Id also induced an increase in anti-Tg. D8.Id was induced in other strains by the same schedule but it only appeared to be associated with anti-Tg in 129 and, to a lesser extent, BALB/c mice, both of which have the allotype Iga. The extent of the overlap between the D8 Id and the anti-Tg was estimated and shown to be greatest in the CBA strain from which the D8 clone was originally derived. Spectrotypic analysis of the induced Ids in CBA mice showed that some of the D8.Id, but none of the G4.Id, was identical to the original clonotype, implying that CBA mice normally have cells which can be induced to produce D8.Id-positive autoanti-Tg, which are normally weakly expressed or regulated. The observation that anti-D8.Id priming in some strains increased D8.Id-negative anti-Tg responses suggests that the D8.Id may also be associated with anti-Tg T-cells.

Animals↗
PubMed1985

Antigenic determinants of human thyroglobulin differentiated using antigen fragments.

Human thyroglobulin (Tg) was digested with V8 protease and the fragments separated by high performance liquid chromatography (HPLC). The antigenic relationship of the fragments was investigated using mouse monoclonal antibodies to human Tg. The binding of Hashimoto's disease autoantibodies to the fragments was measured by radioimmunoassay. This demonstrated that a minority of the patients recognize an epitope on Tg which others do not. The epitopes identified by the autoantibodies were substantially destroyed in the smaller fragments tested, but these smaller fragments were more efficient stimulators of Tg-specific T-cell lines than the larger fragments which carry the antibody binding determinants. This suggests that the parts of the Tg molecule which stimulate autoimmune B cells differ from those which stimulate T cells.

Animals↗
PubMed1985

Serum IL-2 inhibitor in mice. II. Molecular characteristics.

The molecular characteristics of a serum IL-2 inhibitor were determined by fractionating active sera from normal and malaria-infected mice, and assaying inhibitory activity in blocking production and expression of IL-2 activity. Using isoelectric focusing and ion exchange chromatography, the activity resolved in a single peak (pI = 6.2). HPLC gel filtration resolved two peaks of activity (50,000 and 25,000 MW) which are probably related. The molecule is precipitated by 50% saturated ammonium sulphate, and is destroyed by heating above 56 degrees or by acidification below pH 4.

Animals↗
PubMed1984

A common epitope identified by a monoclonal antibody, MID 2, present on all leucocytes and associated with a group of high molecular weight glycopeptides.

A monoclonal antibody, MID 2, which reacts with an epitope common to all human leucocytes, was used to show that the leucocyte common antigen can be resolved into four glycoprotein components with molecular weights of 220 K, 200 K, 180 K and 160 K. The 200, 180 and 160 K peptides were all present to various extents in the T and B lymphoblastoid cell lines examined, but the 220 K component was only detected in the B-cell lines. The 220 K glycoprotein was also lacking in human thymocytes, but evidence of its expression in peripheral blood T lymphocytes was obtained, suggesting that it might be acquired as the cells differentiated. The four glycoproteins isolated from tonsil cells gave similar patterns on peptide mapping by the Cleveland enzymatic method or by cyanogen bromide cleavage, indicating extensive homology. It is conceivable that they differ from each other by the acquisition of similar repeating domain sequences of approximately 20 K. Alternatively, they may share a common peptide structure but differ in their electrophoretic behaviour in SDS gels owing to differences in carbohydrate; if this is the case, however, experiments with tunicamycin suggest that O-linked oligosaccharides must be involved.

Animals↗
PubMed1983

The occurrence of defined idiotypes on autoantibodies to mouse thyroglobulin.

Anti-idiotypic antibodies were raised in rabbits to three monoclonal mouse autoanti-thyroglobulins. Of the idiotypes recognized, one was unique to that monoclonal, while the other two showed evidence of sharing idiotopes with other monoclonal anti-thyroglobulin (TG) idiotypes, the IgM idiotype in particular being found on nearly half of the hybridomas studied. Two of the idiotypes could be detected in the sera of mice with experimental allergic thyroiditis (EAT), but they constituted only a very small percentage of the total anti-TG present. In spite of its low levels in EAT mice the D8 idiotype could be induced by injection of anti-idiotype and TG and in this case it constituted up to 20% of the anti-TG activity in individual mice, showing a strain-related association between the idiotype and autoanti-TG.

Animals↗
PubMed1983

A rapid assay for immunoglobulin in hybridoma supernatants.

A single step assay is described which allows detection of IgM and IgG in tissue culture supernatants at concentrations below 100 ng/ml. The assay is based on the agglutination of staphylococcal protein A coated sheep red blood cells (E-spA) in the presence of an enhancing antibody. The assay was designed for the rapid screening of antibody production by hybridoma cultures.

Animals↗