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Biomedical subjects

L K Trejdosiewicz

Publications and source records attributed to L K Trejdosiewicz.

At least 19 recordsLinked to original sources
PubMed1992

Intestinal intraepithelial lymphocytes and lymphoepithelial interactions in the human gastrointestinal mucosa.

Although representing a major immunological apparatus, it is not known how the immune system of the intestinal mucosa differentiates between dietary antigens (resulting in systemic tolerance) and potential pathogens. It is thought that intraepithelial T lymphocytes (IEL) may play a central role in local intestinal immunity and are likely to be important in immunity to gastrointestinal neoplasms and rejection responses to gut allografts. However, the biology of IEL and their unusual immunological microenvironments in the gastrointestinal mucosa are little understood. IEL are predominantly CD8+ TcR alpha beta+ CD3+ T cells which differ from lamina propria and peripheral T cells in many respects. IEL show low expression of CD5, CD6, LFA-1 (CD11a/CD18) and VLA-4, and high expression of HML-1. TcR gamma delta + IEL, although a minority population, are also phenotypically distinct, insofar as they are 50% CD8+, mainly V delta 1+ V gamma 9- and CD4- CD5-. IEL show poor proliferative responses to PHA, anti-CD3 and phorbol ester/calcium ionophore in vitro and have no clear functional role: they neither provide helper nor suppressor functions for Ig synthesis by B cells and do not mediate spontaneous cytotoxicity. However, there is evidence that IEL show preferential activation in response to sheep erythrocytes, presumably signalling via CD2. As normal and inflamed intestinal epithelia do not express ICAM-1, it seems unlikely that the LFA-1/ICAM-1 interaction is of importance to IEL activation. Rather, the CD2 (LFA-2) interaction with LFA-3 expressed by enterocytes may serve both to anchor IEL and to provide an accessory stimulus for activation. Nevertheless, the questions of antigenic specificity and immunological role remain unanswered.

Antigen-Presenting Cells↗
PubMed1992

Intracellular free Ca2+ fluxes and responses to phorbol ester in T lymphocytes from healthy elderly subjects.

A group of healthy elderly subjects (greater than or equal to 75 years) was selected by the strict criteria of the SENIEUR protocol, and compared with healthy young (less than or equal to 35 years) volunteers. Mitogenic responses of peripheral blood mononuclear cells to phytohaemagglutinin and anti-CD3 were significantly reduced in the elderly (P less than 0.0002), thereby confirming that even though in perfect health, elderly individuals show impaired cell-mediated immunity. However, no abnormality of intracellular free Ca2+ fluxes could be detected in purified T cells from the elderly subjects when stimulated with anti-CD3 antibody. Nevertheless, both the proliferative responses of purified T cells to phorbol ester and calcium ionophore (Ionomycin) and the phorbol ester-induced inhibition of the Ca2+ response were defective in the elderly subjects (P less than 0.003 and P less than 0.0002, respectively). These data suggest that signal transduction and the generation of second messengers proceed normally in T cells from the elderly, but downstream events mediated by activation of protein kinase C are dysfunctional.

Adult↗
PubMed1992

Impaired proliferative responses of peripheral blood B cells from splenectomized subjects to phorbol ester and ionophore.

The responses of peripheral blood B cells to mitogenic stimulation were examined in 12 splenectomized subjects without residual splenic function, as determined by pitted erythrocyte counts. These were compared to a group of healthy controls matched for age and sex. Polyclonal anti-immunoglobulin evoked a normal transient elevation in intracellular free Ca2+ in splenectomized subjects, thereby suggesting that the early events of the signal transduction pathway are not impaired. However, mitogenic stimulation by pre-treatment with phorbol ester and culture in presence of a calcium ionophore (Ionomycin) resulted in reduced uptake of 3H-thymidine and subsequent proliferation. Nevertheless, entry into the mitotic cycle, as assessed by expression of Ki67, was slightly, but not significantly impaired. Unlike in normal controls, where up to 7% of freshly-isolated B cells were Ki67+, almost no Ki67+ peripheral B cells were observed in splenectomized subjects. The data are consistent with the hypothesis that peripheral B cells in splenectomized subjects are in a reduced state of activation compared with normal controls and require additional growth factor stimulation before they can undergo mitosis.

Adolescent↗
PubMed1992

Murine intestinal humoral responses in chronic Schistosoma mansoni infections.

Specific and non-specific production of immunoglobulins (Ig) by the intestinal mucosa was examined in mice infected with the human blood fluke Schistosoma mansoni. Ileal and colonic mucosal tissue samples were cultured for 2 days, the medium replaced and the culture continued for a further 2 days. Ig concentrations and specific antibodies to soluble schistosome egg antigens in culture supernatants were estimated by isotype-specific ELISA. Cultured mucosae from control mice produced little IgG, but significant amounts of IgA and IgM on prolonged culture. IgG concentrations were increased in infected animals, mainly in the initial culture period, indicative of systemic, rather than local origins. By contrast, significantly increased local production of IgA and IgM occurred after the start of egg deposition in the intestinal mucosae. Although specific anti-egg antibodies of the IgG and IgM class were detected, none of the local IgA response was specific for schistosome eggs. We conclude that specific intestinal immune responses to schistosome eggs reflect systemic responses, whereas locally increased IgA production is largely non-specific. This pattern of response is likely to be related to the prior systemic exposure to schistosome eggs, which results in polyclonal local B-cell activation, but fails to trigger an antigen-specific IgA mucosal response.

Animals↗
PubMed1992

Specific circulating anti-gliadin IgG-class antibody does not mediate intestinal enteropathy in gliadin-fed mice.

The effects of specific circulating IgG antibody on the uptake of dietary antigen and in the generation of intestinal enteropathy have been investigated in Balb/c mice bred on a gluten-free diet. A monoclonal IgG1 antibody (GD3) was prepared against gliadin. After adoptive transfer into mice, this antibody was capable of mediating a type III hypersensitivity response in vivo to footpad challenge with gliadin. The titres of circulating GD3, as estimated in vitro by ELISA, correlated well with the degree of inflammation at sites of type III responses in vivo. Following footpad challenge with gliadin, titres of circulating GD3 antibody were reduced. GD3 antibody was tested for its ability to mediate inflammatory responses in vivo in the intestinal mucosa of mice fed with gliadin. Circulating GD3 antibody was removed selectively and specifically by dietary gliadin, compared to feeding with bovine serum albumin or maintenance on a gliadin-free diet only. However, we were unable to demonstrate any pathological changes in the intestine as a result of possible local antigen-antibody complex formation or deposition. Using radio-iodinated gliadin as a trace marker, no significant retention of gliadin in the intestinal mucosa was found in mice pre-injected with GD3 antibody. These data suggest that circulating IgG antibody has little effect on dietary antigen uptake in the gut, and alone is insufficient to mediate an enteropathy.

Animals↗
PubMed1992

Regulation of intestinal immunoglobulin production in response to dietary ovalbumin.

The effects of oral administration of ovalbumin (OVA) on intestinal immunoglobulin production was examined. Balb/c mice, bred and reared on an OVA-free diet, received either one dose or 14 consecutive daily intragastric doses of 25 mg OVA/dose. Single dose administration of OVA resulted in significant suppression of total immunoglobulins in the intestinal mucosa, particularly of the IgA isotype, although a very low titre anti-OVA IgG class antibody response was induced. After multiple peroral immunisations, there was more intestinal anti-OVA antibody induction and less suppression of total immunoglobulins. However, all the anti-OVA antibody was of the IgG isotype. In vitro production of mucosal immunoglobulins was not significantly reduced over 5 days, compared with controls, in either single or multiple administration groups, suggestive of a loss of T suppressor cell function in culture. Prior adoptive transfer of splenic and lymph node cells from mice preimmunised with OVA was capable of abrogating the local suppression of immunoglobulin production in vivo. Although adoptive transfer of bovine serum albumin-sensitised cells could also overcome some of the local suppression, complete restoration of normal immunoglobulin levels was not achieved. These data suggest that single oral administration of a novel dietary antigen induces a transient, non-specific suppression of intestinal immunoglobulin production, which can be overcome by antigen-specific T cells.

Administration, Oral↗
PubMed1992

Intracellular actin as a marker for myofibroblasts in vitro.

BACKGROUND: Myofibroblasts are found in a wide variety of normal tissues and pathological conditions. It is suggested that myofibroblasts are derived from normal fibroblasts and share with smooth muscle cells the expression of actin microfilament bundles. The aim of this study was to establish if the myofibroblast phenotype from tissue expander capsules and Dupuytren's nodules could be distinguished from normal dermal fibroblasts by quantitation of intracellular actin and the ratio of polymerized (filamentous) actin to nonpolymerized (globular) actin. EXPERIMENTAL DESIGN: Cell lines were established from six patients from each group. In addition to quantitation of intracellular actin, the cells were characterized by criteria of light microscopy, ultrastructure, actin immunofluorescence, and growth rates. RESULTS: Dermal fibroblasts were the smallest and the most spindle-shaped but grew rapidly and had few actin microfilament bundles. By contrast, myofibroblasts from expander capsules were larger and more stellate, proliferated slowly, and had the most prominent microfilament arrays. Cells from Dupuytren's nodules were intermediate in phenotype. Substantial and significant differences in intracellular actin contents were found, ranging from 0.69 +/- 0.05 micrograms/10(4) cells in fibroblasts and 0.77 +/- 0.15 micrograms/10(4) cells for Dupuytren's nodule cells to 1.46 +/- 0.44 micrograms/10(4) cells in expander capsule myofibroblasts (p < 0.05). Similar findings were found with respect to ratios of fibroblast to globular actins, being 0.22 for fibroblasts and 0.38 for Dupuytren's nodule cells compared with 0.70 for expander capsule myofibroblasts (p < 0.01). CONCLUSIONS: Measurement of intracellular actin contents and fibroblast:globular actin ratios offers a rapid, sensitive, and reliable technique for establishment of the myofibroblast phenotype and has considerable advantages over traditional ultrastructural approaches for the study of myofibroblast differentiation/regression and in vitro responses to experimental manipulation.

Actins↗
PubMed1991

Expression of leukocyte adhesion molecules by mucosal mononuclear phagocytes in inflammatory bowel disease.

Leukocyte adhesion molecules are important in cell-cell interactions of the immune system. Lymphocyte function-associated antigen 1 (cluster designation 11a) mediates interactions between T cells and mononuclear phagocytes through its ligand, the intercellular adhesion molecule 1 (CD54), whereas complement receptors 3 (CD 11b) and 4 (CD11c) are involved in complement-mediated phagocytosis. Expression of CD11 molecules and intercellular adhesion molecule 1 was studied in colonic biopsy specimens from 20 patients with inflammatory bowel disease and 10 normal controls. In normal colon, few mononuclear phagocytes expressed lymphocyte function-associated antigen 1 and intercellular adhesion molecule 1 at high densities. The major adhesion molecule was CD11c. Thus, the largest population of normal colonic mononuclear phagocytes was represented by quiescent, resident macrophages with likely phagocytic function. In inflammatory bowel disease, mononuclear phagocytes showed only a slight increase in CD11a expression and no significant change in expression of CD11b and CD11c. By contrast, the percentage of mononuclear phagocytes expressing intercellular adhesion molecule 1 was increased from 6.9% +/- 3.9% in controls to 69.2% +/- 12.8% in ulcerative colitis (P less than 0.001) and to 45.7% +/- 22.8% in Crohn's disease (P less than 0.01), showing a close relationship with histological activity. The increased expression of intercellular adhesion molecule 1 in inflammatory bowel disease indicates a state of immunological activation induced by local release of inflammatory cytokines. Such induction of intercellular adhesion molecule 1 on mononuclear phagocytes may be important in the maintenance of chronic inflammation by facilitating interactions with T cells and T-cell antigen recognition.

Adult↗
PubMed1991

Expression of the LFA-1 beta 2 integrin (CD11a/CD18) and ICAM-1 (CD54) in normal and coeliac small bowel mucosa.

The leucocyte adhesion molecules (beta 2 integrins) comprise CD11 alpha-chains and a common beta-chain (CD18). CD11a (leucocyte function-associated antigen 1, LFA-1) is expressed by most T cells, and is involved in antigen presentation by macrophages via its counter-receptor, intercellular adhesion molecule (ICAM-1, CD54). By criteria of double-label immunofluorescence of cryostat tissue sections, virtually all lamina propria T cells of the normal small bowel were found to express LFA-1 strongly. By contrast, only 30-60% of intra-epithelial lymphocytes (IEL) expressed detectable LFA-1, most of which were LFA-1 weak and CD18-. ICAM-1 was expressed strongly only by vascular endothelium. In coeliac disease, there was a modest increase of diffuse ICAM-1 expression in the lamina propria, mainly in the subepithelial zone, where ICAM-1+ macrophages were occasionally seen. There was also a slight overall increase in CD11a expression by IEL, seen predominantly in surface epithelium and mainly by the CD4+ minority subset, but not by CD4-CD8- (TcR gamma delta +) cells. These data suggest that the LFA-1/ICAM-1-dependent antigen presentation pathway is of minor importance to IEL in the normal small bowel, and does not assume a major role in coeliac disease.

Antigens, CD↗
PubMed1991

Gamma delta T cell receptor-positive cells of the human gastrointestinal mucosa: occurrence and V region gene expression in Heliobacter pylori-associated gastritis, coeliac disease and inflammatory bowel disease.

T cells expressing the gamma delta heterodimer of the T cell receptor (TCR) were studied with respect to their occurrence and expression of gamma delta TCR variable region (V) genes in the normal gastrointestinal mucosa and in a variety of inflammatory conditions. In controls, gamma delta TCR+ cells were a minority population confined to the epithelial compartment of stomach, small bowel and colonic mucosae. Unlike in the periphery, gastro-intestinal gamma delta TCR+ intraepithelial lymphocytes (IEL) were mainly V delta 1+ (89.98 +/- 17.70%); few were V delta 2+ (6.04 +/- 13.8%) or V gamma 9+ (11.38 +/- 10.73%). All gamma delta TCR+ IEL were CD5low; nearly half were CD8+ and the remainder were CD4-CD8- 'double negatives'. There was no significant change from normal in percentages of gamma delta TCR+ IEL in H. pylori-associated gastritis, Crohn's disease and ulcerative colitis. However, in coeliac disease, gamma delta TCR+ IEL were elevated from 2.54% (+/- 1.71) in controls to 29.6% (+/- 16.1) in untreated patients (P less than 0.001) and 18.5% (+/- 7.2) in treated patients (P less than 0.001) and more were CD4-CD8-. Otherwise, gamma delta TCR+ IEL phenotypes were little changed: the majority remained V delta 1+V delta 2-V gamma 9- and all were CD5low. These data suggest that increased gamma delta TCR+ IEL are not a generalized response to intestinal inflammation or to stress proteins, although the typical V delta 1+V delta 2-V gamma 9- CD5low phenotype is retained.

Adult↗
PubMed1990

T lymphocyte stimulation of human small intestinal glycoprotein biosynthesis: effects of anti-CD3 antibody on normal and coeliac mucosa.

The effects of mucosal T-cell activation on human small intestinal glycoprotein biosynthesis have been examined during short-term culture in vitro. The incorporation of 3H-glucosamine into tissue and secreted glycoproteins was determined. Activation of mucosal T lymphocytes of normal duodenal biopsies with the monoclonal anti-CD3 antibody significantly increased both the total glucosamine incorporation into glycoproteins (p less than 0.01) and the secretion of in vitro radiolabelled glycoproteins (p less than 0.001). This effect was inhibited by ciclosporin. Secretion of glycoproteins was also stimulated by culture with pokeweed mitogen. In patients with coeliac disease, culture of small intestinal biopsies with anti-CD3 antibody significantly increased (p less than 0.05) glycoprotein biosynthesis in treated patients, but had no stimulatory effect in untreated patients with villous atrophy. These results show that activation of mucosal T lymphocytes induces quantitative changes in intestinal glycoprotein synthesis and secretion and T lymphocytes therefore have an important role in non-specific intestinal defences. The results are consistent with the suggestion that increased glycoprotein synthesis and secretion in untreated coeliac mucosa result from T-cell activation.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Effects of linoleic acid and mitogenic stimulation on the fatty acid composition of human lymphocytes.

Perturbation of the fatty acid composition of human lymphocytes in vitro was investigated by addition of linoleic acid complexed to bovine serum albumin (BSA-LA) and by mitogenic stimulation with phytohaemagglutinin (PHA). BSA-LA resulted in a 45% increase in linoleic acid in phosphatidylethanolamine (PE) and over 100% in phosphatidylcholine (PC) in peripheral blood cells. Supplementation with BSA-LA in PHA-stimulated lymphocytes produced even greater changes: 100% increase in linoleic acid content for PE and over 300% for PC. There was a large decrease in oleic acid: 40% for PE and almost 100% in PC. Significant decreases in arachidonic acid occurred in both phospholipid fractions. PHA alone also altered membrane phospholipid fatty acid composition, with reductions in palmitic, stearic and linoleic acid for PE and increases in oleic acid and arachidonic acid (almost 100%). For PC, there were large decreases in stearic (40%), linoleic (30%) and arachidonic (40%) acids, together with an increase in oleic acid (65%). Cells supplemented with linoleic acid grown in the presence of PHA, compared with those grown in linoleic acid-supplemented medium alone, showed a 40% decrease in palmitic acid and a 55% increase in arachidonic acid in PE. For PC, there were large decreases in stearic acid (40%) and arachidonic acid (57%). Antibody-induced redistribution of surface molecules ('capping') was inhibited by some 14% after incubation with BSA-LA. However, no consistent alterations in PHA-induced cell proliferation were observed. These data suggest that profound alterations of membrane fatty acid composition occur spontaneously during the mitotic cycle, and may be further induced by experimental manipulation, without gross perturbation of cell function.

Arachidonic Acid↗
PubMed1989

Colonic mucosal T lymphocytes in ulcerative colitis: expression of CD7 antigen in relation to MHC class II (HLA-D) antigens.

T-cell subsets and their activation state were examined by double-label immunofluorescence of cryostat tissue sections of the colon from 21 patients with ulcerative colitis (UC) and 30 histologically normal controls. Expression of MHC class I (HLA-A, B, C) and class II (HLA-D) antigens was studied in parallel. In the normal colonic mucosa, the CD4:CD8 ratio in the epithelial compartment approximated 1:1, and in the lamina propria, 2.55:1. Of the CD8+ (cytotoxic/suppressor) subset, approximately half did not express the CD5 "pan-T" marker in either compartment. Virtually no Leu8+ cells were observed, implying that the CD4+ subset consisted of helper, rather than suppressor-inducer cells. Classical markers of T-cell activation (CD25, HLA-D) and proliferation were absent, and strong expression of the CD7 "immunostimulation" marker was approximately equal in both CD4 and CD8 subsets. The epithelium was uniformly negative for class II antigens, but positive for class I. In UC, there were no significant alterations in CD4:CD8 ratios in either compartment, and there were no changes with respect to phenotype of the subsets. In 11 of 19 patients (mainly with total colitis), enterocytes were HLA-D+. In this HLA-D+ group, there was an increase in the percentage of CD4+ cells coexpressing CD7; this difference was significant (P less than 0.02) in the lamina propria. Increased expression of CD7 was also found by the CD6+ T cell subset (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Responses of antigen-specific long-term murine T cell lines to wheat gliadin fractions.

Recent evidence suggests that the four electrophoretically defined gliadin subfractions (alpha, beta, gamma and omega) of wheat can induce the typical pathological finding of coeliac disease. We have prepared long-term murine T cell lines to gliadin and its four major subfractions. The cell lines were tested in proliferative assays with each homologous gliadin subfraction, and to the other gliadin subfractions. There was some cross-reactivity, with unfractionated gliadin and its alpha-subfraction being the most antigenic, while omega-gliadin was the least. These data demonstrate that gliadin components are effective stimuli for specific T cell responses, and further suggest that the alpha-gliadin subfraction generates the highest specific responses. This accords with observations in man that all four gliadin subfractions exacerbate coeliac mucosa, but that the alpha-subfraction is the most active.

Animals↗
PubMed1989

Lack of a serologic response to an E1B protein of adenovirus 12 in coeliac disease.

The description of an amino acid sequence homology between the E1B-58-kDa protein of adenovirus 12 and gliadin has led to the suggestion that previous infection by this virus and subsequent exposure to gliadin could trigger the development of coeliac disease in susceptible individuals as a result of immunologic cross-reactivity. We have sought to measure specific antibodies to the E1B-58-kDa protein in 23 coeliac patients and 10 normal subjects. The sera were analysed by radioimmunoprecipitation with metabolically labelled adenovirus-12-transformed rat cells (which express the E1B-58-kDa protein), followed by separation on polyacrylamide gels. None of the coeliac sera had evidence of antibodies to the E1B-58-kDa protein. These data suggest that coeliac patients show little evidence of humoral immunity to the specific adenovirus 12 E1B-58-kDa protein implicated in the aetiology of coeliac disease.

Adenovirus Early Proteins↗
PubMed1989

Expression of T-cell receptors TcR1 (gamma/delta) and TcR2 (alpha/beta) in the human intestinal mucosa.

Cryostat sections of normal human adult gastrointestinal mucosae were studied by double-label immunofluorescence with antibodies to CD3, CD4, CD8, CD5 and CD6, in parallel with antibodies beta F1 and TCR delta 1 against beta-chains and delta-chains of the T-cell receptor (TcR) types TcR2 (alpha/beta) and TcR1 (gamma/delta), respectively. Virtually no TcR1+ were found within the lamina propria. In the epithelial compartment, TcR1+ cells were infrequent: in the small bowel, congruent to 2% of T cells were TcR1+. In the colonic epithelium, the percentage of T cells expressing gamma/delta-chains was higher, with a mean value approximating 15-20%, although this apparently large percentage increase compared with small bowel reflects in part a much lower density of colonic IEL, as absolute numbers of TCR delta 1+ cells were comparable. Of the TcR1+ population, about half were CD4- CD8-, 'double negatives' and the remainder were CD8+. TcR1+ cells were also CD5- CD6-, irrespective of expression of CD8. No CD4+ cells expressing TcR1 were observed: essentially all CD4+ cells were beta F1+, with some variability of labelling intensity. Approximately 30-50% of the CD8+ subset expressed the beta F1 antigen strongly. However, in the remaining TcR1- CD8+ cells, which were all of the CD5- CD6- phenotype, expression of the beta F1 antigen was only detectable when streptavidin and biotin conjugates were used for amplification of labelling. Thus, the CD8+ CD5- subset, a prominent population of the epithelial compartment of the small bowel, was either TcR2dull in the majority or TcR1+ in a minority. Our data imply that gamma/delta TcR1 cells may be actively excluded from intestinal lamina propria, and that any preferential localization that does occur is limited and is rather a feature of the colonic mucosa, rather than the small bowel.

Humans↗
PubMed1988

T lymphocytes of the human colonic mucosa: functional and phenotypic analysis.

Normal human colonic lymphocyte populations were isolated for both phenotypic analysis by double-label immunofluorescence and assessment for regulatory effects on Ig production by co-culture with responder cells from colonic mucosa and peripheral blood. Mean CD4:CD8 ratios for colonic intraepithelial lymphocytes (IEL) and lamina propria lymphocytes (LPL) were comparable to values obtained from tissue sections. IEL alone did not produce Ig in vitro and were without effect on Ig production when co-cultured with LPL. However, T-enriched LPL had a marked helper effect for T-depleted LPL. Maximal help was for IgA production, increasing with numbers of T-enriched cells. In colonic LPL T-depleted and T-enriched co-cultures, pokeweed mitogen (PWM) had no significant effect. By contrast, in co-cultures of T-enriched and T-depleted peripheral blood mononuclear cells, Ig production was PWM-dependent. In all experiments with colonic mucosal responder cells, IgG production was low. The effects of unfractionated colonic biopsy lymphocytes on T-depleted peripheral blood mononuclear cells were additive for IgM production and synergistic for IgA synthesis, although almost no IgG was produced. Moreover, PWM had helper effects for IgM, but was suppressive for IgA production. These data suggest that colonic mucosal regulatory cells reside in the lamina propria, and predominantly provide help for IgA and IgM synthesis. The data further suggest the existence of a pre-stimulated IgA-specific T helper cell population.

Antigens, Surface↗