PubMed Health⌕ Search

Biomedical subjects

F Spinozzi

Publications and source records attributed to F Spinozzi.

At least 73 records · Page 4Linked to original sources
PubMed1993

Lymphocytes bearing the gamma delta T cell receptor in acute Brucella melitensis infection.

A phenotypical analysis carried out by indirect immunofluorescence and two-color cytofluorometry showed that the number of lymphocytes bearing the gamma delta T cell receptor (TcR) heterodimer was dramatically increased in the blood of six children with Brucella melitensis infection. Most in vivo expanded gamma delta T cells reacted with a monoclonal antibody which identifies V delta 2 gene products and a significant proportion expressed CD25 and HLA-DR activation antigens. In addition, whereas only a few gamma delta T lymphocytes were CD8+, nearly all were CD4-. Highly enriched populations of both alpha beta and gamma delta T cells were obtained by negative immunoselection from three subjects with brucellosis sampled during convalescence. Despite the different form of their TcR, the proliferation of these two major T cell subsets in response to a mitogenic anti-CD3 monoclonal reagent (OKT3) was optimal. In contrast, alpha beta, but not gamma delta, T lymphocytes proliferated vigorously in response to the antigenic stimulus elicited by heat-killed Brucella. Further studies are, therefore, needed to determine whether the selective expansion of the gamma delta T cell subpopulation observed during the clinical course of the infection is driven by antigenic determinant(s) borne by the pathogen in vivo or is due to host-derived stimuli, such as autologous heat-shock proteins expressed on the surface of the infected cells.

Acute Disease↗
PubMed1993

Ethanol-specific impairment of T-lymphocyte activation is caused by a transitory block in signal-transduction pathways.

BACKGROUND: Immune system derangement is characteristic of alcoholic liver cirrhosis. However, in vitro studies have never clarified the alcohol-induced T-lymphocyte dysfunction. The aim of this study was to examine any discrete phenotypical and functional abnormalities and possible impairment in transmembrane signal-transduction pathways that, if present on lymphocytes of patients with alcoholic cirrhosis, would also be reproducible after in vitro ethanol exposure of normal T cells. METHODS: Lymphocytes from 25 patients were analyzed for their in vitro proliferative functions, intracellular Ca2+ fluxes, and inositol 1,4,5-triphosphate (IP3) generation. The same procedures were applied to normal T cells exposed in vitro to ethanol. RESULTS: Lymphocytes failed to respond to anti-CD3 and anti-CD2 after in vitro stimulation, with decreased intracellular Ca2+ mobilization and IP3 generation but showed normal proliferative response to phytohemagglutinin. In vitro ethanol incubation of normal T lymphocytes resulted in rearrangement of the membrane CD45 antigen, favoring the expression of high-molecular-weight isoforms, and showed a poor blastogenic response to anti-CD3 and anti-CD2 with a decrease in intracellular Ca2+ mobilization and IP3 production. After a 6-month period of ethanol withdrawal, some patients had normalization of phenotypic and functional alterations. CONCLUSIONS: The T-lymphocyte response to specific polyclonal activators may be severely impaired in alcohol abusers. However, it seems reversible after a period of controlled ethanol withdrawal.

Adult↗
PubMed1993

Alteration of membrane transductive mechanisms induced by ethanol in human lymphocyte cultures.

Ethanol, in millimolar concentrations, significantly modifies different transductive systems in human lymphocyte cultures. In particular, the presence of alcohol in the medium more than doubles the [Ca2+]i (from 70-90 to 200-250 nM), increasing Ca2+ fluxes from outside, and inhibits the active transport carried out by the calcium pump. The Ca2+ release from intracellular stores is not involved because 10 mM EGTA in the medium completely abolished the rise of [Ca2+]i. Since IP3 levels and cAMP concentrations are also involved in ethanol events (although with opposite effects), it seems that the alcohol may have a specific target on cell membranes (G-proteins) which influence many transductive pathways.

Alcohol Drinking↗
PubMed1993

Genistein inhibits tumour cell growth in vitro but enhances mitochondrial reduction of tetrazolium salts: a further pitfall in the use of the MTT assay for evaluating cell growth and survival.

The natural isoflavone genistein inhibits the growth of a number of tumour cell lines in vitro. During investigations on the antiproliferative effects of genistein we observed that, with respect to direct cell counting, a tetrazolium (MTT) colorimetric assay consistently underestimated the growth inhibitory activity of the substance. Cell proliferation was markedly inhibited by genistein in three tumour cell lines (MCF-7, human breast tumour; Jurkat cells, human T-cell leukaemia; L-929, mouse transformed fibroblasts) when cell number was evaluated by direct counting, whereas a 72-h MTT assay failed to reveal any growth-inhibitory effect. Cell cycle analysis by propidium iodide staining and flow-cytometry revealed a G2/M cell cycle arrest after genistein treatment. Genistein-treated cells displayed an increase in cell volume and in mitochondrial number and/or activity, as revealed by enhanced formazan generation and increased uptake of the vital mitochondrial dye rhodamine 123. These results suggest that alterations in cell cycle phase redistribution of tumour cells by genistein may significantly influence mitochondrial number and/or function and, consequently, MTT reduction to formazan. This may constitute an important bias in analysing the effects of genistein, and possibly other drugs that block the G2/M transition, on growth and viability of cancer cells in vitro by MTT assay.

Animals↗
PubMed1992

Lymphocytes bearing the gamma/delta T-cell receptors in Down's syndrome.

Subjects with Down's syndrome (DS), or trisomy 21, have an increased susceptibility to infections, malignant diseases and autoimmune phenomena. Various arms of the immune system are severely impaired in trisomic patients. We found that the proportion of blood lymphocytes bearing the gamma/delta T-cell receptor (TCR) was significantly higher in adults with trisomy 21 than in age- and sex-matched healthy controls. Interestingly, the increase was mainly due to an over-expansion of cells which bear non-covalently bound gamma/delta chains on their surface. This contrasts with the normal blood picture, where the great majority of gamma/delta T cells express the disulphide-linked form of the TCR. The fact that trisomic gamma/delta T cells are both numerically and phenotypically unbalanced provides further evidence that immunological abnormalities are integral features of DS.

Adult↗
PubMed1992

Ethanol-induced CD3 and CD2 hyporesponsiveness of peripheral blood T lymphocytes.

The functional relevance of a direct ethanol effect on the membrane structure of T lymphocytes and accessory cells (APC), as well as on signal transduction systems was studied in ten normal subjects. Ethanol incubation (80 mM for 24h) of highly purified T cells increased the number of CD4+/CD45RA+ lymphocytes. In contrast, ethanol exposure induced a drop in CD14+/LFA-3+ APC values. These changes were accompanied by faulty T-cell proliferation in response to anti-CD3 and anti-CD2 mAb and inhibition of CD3- and CD2-mediated rises in intracellular calcium and, to a lesser extent, inositol 1,4,5-triphosphate levels. These data clearly indicate that a membrane-specific ethanol interaction both modifies surface glycoproteic and/or glycolipidic structures and alters transmembrane transduction of the activation signals.

Antibodies, Monoclonal↗
PubMed1992

Lymphocytes bearing the gamma delta T-cell receptor in acute toxoplasmosis.

Although the relative and absolute numbers of CD3+ cells (T lymphocytes) were similar in eight children with acquired Toxoplasma gondii infection and 10 uninfected age- and sex-matched healthy controls, the proportion of cells bearing the gamma delta T-cell receptor was significantly higher in the subjects with acute toxoplasmosis. The great majority of gamma delta T cells from the infected patients expressed covalently bound gamma delta chains on their surface, i.e. were BB3+ lymphocytes. Since the gamma delta T-cell subsets exert both restricted and unrestricted major histocompatibility complex cytotoxicity, further research is needed to elucidate the role of gamma delta T cells in the control of this coccidian protozoan infection.

Acute Disease↗
PubMed1992

IgG subclass deficiency and sinopulmonary bacterial infections in patients with alcoholic liver disease.

Abnormalities in IgG subclass distribution were sought in serum samples and bronchoalveolar lavage fluid from 15 patients with alcoholic liver disease to explain their increased susceptibility to bacterial respiratory infections. Serum IgG4 deficiency alone or in association with low IgG2 levels was revealed in approximately 30% of patients with alcoholic liver disease. This fact prompted us to further investigate the immunoglobulin concentrations in broncho-alveolar lavage fluid, paying special attention to the distribution of IgA and IgG subclasses. IgA levels were found to be normal or slightly elevated. However, there were substantial defects in total IgG and IgG1 concentrations, often associated with reduced IgG2 and IgG4 levels, in approximately 70% of patients with alcoholic liver disease, which proved to be closely correlated with the number and type (pneumonia) of bacterial respiratory infections. A prospective study of intravenous immunoglobulin substitutive therapy involving two patients with recurrent pneumonia and very low serum IgG2 values demonstrated a reduction in the number of respiratory infectious episodes as well as an increase in both serum and, to a lesser extent, bronchoalveolar lavage fluid IgG1 and IgG2 levels. We identified immune defects that may represent an important pathogenetic mechanism that, when considered together with the alcohol-related suppression of alveolar macrophage and ciliary functions and the inhibition of leukocyte migration into the lungs, should help clarify the complex relationships between alcohol and immune defense.

Adult↗
PubMed1991

[Immunotherapy in allergic diseases. Evaluation of short-term efficacy of aluminum hydroxide-absorbed slow-release preparations].

Clinical and immunological changes after immunotherapy (ITS) for respiratory allergy were evaluated in 29 subjects during a one year follow up period. No adverse effects were noted with alum-absorbed allergen extracts. However, only patients receiving ITS for grass pollens demonstrated clinical improvement and blocking IgG increase as compared with those with multiple allergen sensitivity.

Adolescent↗
PubMed1991

T-lymphocyte activation pathways in alcoholic liver disease.

Immune system derangement in cirrhotic patients with evidence of malnutrition is a well-recognized characteristic of chronic alcohol abuse. However, in vitro studies on cellular immune function performed with lectin mitogens have produced conflicting results. The recent development of more accurate immunological techniques for studying lymphocyte transformation, that use monoclonal antibodies directed against surface structures (CD3 and CD2) involved in antigen recognition, as well in adhesion functions, prompted us to study discrete in vitro T-cell hypo-responsiveness in a series of alcoholic liver disease (ALD) patients with no evidence of malnutrition or hepatic cirrhosis. The results indicated that the CD2 pathway is markedly defective in ALD T lymphocytes, accompanied by reduced interleukin-2 (IL-2) receptor expression upon in vitro activation. This defect cannot be reversed by the addition of recombinant IL-2 (rIL-2) or rIL-1. Faulty intracellular signal transduction by protein kinase C (PKC) and defective intracellular Ca2+ mobilization may be responsible for the CD2 pathway impairment. The addition of small amounts of phorbol 12-myristate, 13-acetate, but not Ca2+ ionophore A23187, is able to overcome the defect, thereby suggesting a direct PKC involvement. The hypothesis of a direct ethanol effect on transmembrane signal transduction systems is suggested by the demonstration of an expansion of circulating virgin (naive) T cells (CD3+/UCHL1-low) that binds tyrosine phosphatase (CD45RA antigen) on their surface.

Adult↗
PubMed1991

Analysis of T cells bearing different isotypic forms of the gamma/delta T cell receptor in patients with systemic autoimmune diseases.

The expression of gamma/delta T cell receptor (TCR) on peripheral blood CD3+ cells circulating in 74 patients with different systemic autoimmune diseases was evaluated. There was a significant increase in the gamma/delta T cell number only in patients with primary Sjögren's syndrome (SS) and in untreated patients with systemic lupus erythematosus (SLE). Unlike healthy subjects, a subgroup of patients with SLE and SS displayed a marked increase in gamma/delta T cells. Immunosuppressive treatment of patients with active SLE led to a normalization of the gamma/delta T cell number. Analysis of surface phenotype showed that when patient gamma/delta T cells were expanded in the peripheral blood, they were not activated but bore "memory" markers. In addition, they preferentially expressed the disulfide linked form of the TCR, except in progressive systemic sclerosis where the nondisulfide form was displayed. Serial determinations in single patients demonstrated that the gamma/delta T cell increase is a persistent immunological feature in these patient subgroups.

Adolescent↗
PubMed1990

[The determination of specific IgE in allergy diagnosis. The clinical significance of specific IgE in drug allergies].

IgE-mediated allergic reactions to drugs may be diagnosed on the basis of anamnestic criteria, clinico-pathological manifestations as well as by the measurement of allergen-specific IgE. The concordance of these diagnostic procedures was investigated in 50 patients with a history of sensitivity to penicillin (12), sulphamethoxazole (9) or both (14), aspirin (2) and pyrazolones (13). All subjects displayed chronic urticaria/angioedema syndrome. Optimal concordance values were observed for penicillin and sulphamethoxazole, while no specific IgE were detected in the ASA-sensitive group. False positive results were noted in pyrazolone-sensitive patients with high total IgE levels. Based on these results, serological methods that detect drug-specific IgE may be carefully used as complementary diagnostic procedure only in those patients in whom an adverse reaction to antibiotics is suspected.

Antibody Specificity↗
PubMed1990

Activation of cord T lymphocytes. II. Cellular and molecular analysis of the defective response induced by anti-CD3 monoclonal antibody.

Despite the fact that the percentage of circulating CD3-positive cells is similar in cord and adult blood, the proliferative response induced by anti-CD3 monoclonal antibody (mAb) was impaired in the majority of human cord peripheral blood mononuclear cell (PBMC) samples we tested. The cell proliferative defect was associated with low interleukin 2 (IL 2) gene expression and scant IL 2 production. However, interleukin 2 receptor was fully expressed at both the mRNA and protein levels. Such a finding is consistent with the observation that exogenous recombinant IL 2 is able to boost the anti-CD3-mediated response of cord PBMC. Furthermore, when anti-CD3 and phorbol myristate acetate (PMA) were added together, they exerted a very marked synergistic effect on both the proliferation of, and IL 2 production by, cord PBMC. The addition of allogeneic antigen presenting cells plus soluble anti-CD3 or Sepharose-coupled anti-CD3 mAb to the cord T cell cultures had no significant effect on proliferation, whereas both elicited good mitogenesis of adult T cells. Moreover, addition of exogenous recombinant interleukin 1 to anti-CD3-stimulated T cells failed to trigger any proliferation in either adult or cord samples. Since the combination of PMA and calcium ionophore A23187 is effective in triggering optimal proliferation of cord T cells, the defect would seem to be associated with a failure in transmembrane transduction of the activation signals provided by the anti-CD3 stimulus for the cord T cell.

Antigen-Presenting Cells↗
PubMed1990

LF61: a new monoclonal antibody directed against a trimeric molecule (150 kDa, 125 kDa, 105 kDa) associated with hairy cell leukaemia.

The newly produced monoclonal antibody (mAb) LF61 detects a molecule restricted to hairy cell leukaemia (HCL) among B-cell non-Hodgkin's lymphomas. In particular, the percentage of LF61 + HCL cells in different cases ranges from 10% to 100%. In normal lympho-haemopoietic tissues LF61 reacts with only about 2% of T-cells, mostly of the CD8 subset in the peripheral blood, extrafollicular areas of the tonsil, red pulp of the spleen and thymic medulla. Expression of the LF61 molecule is observed following stimulation of peripheral blood lymphocytes with phytohaemagglutinin (PHA) or pokeweed mitogen (PWM), suggesting that it represents an activation antigen. Due to its restricted reactivity with a small subset of normal CD8 + T-cells, LF61 in combination with a CD22 mAb is highly suitable for monitoring residual disease in interferon or deoxycoformicin-treated HCL patients. Polyacrylamide gel gradient electrophoresis shows that LF61 precipitates a 150 kDa, 125 kDa, 105 kDa trimeric molecule from the surface of HCL cells. Immunohistological and immunobiochemical results show that this molecule is the same as the one recognized by the still unclustered anti-HCL mAb B-ly7.

Antibodies, Monoclonal↗
PubMed1990

Basis for defective proliferation of peripheral blood T cells to anti-CD2 antibodies in primary Sjögren's syndrome.

Anti-CD2-induced T cell proliferation was analyzed in the peripheral blood samples of 31 primary and 8 secondary untreated Sjögren's syndrome patients. Anti-CD2-stimulated PBMC proliferation was very low in about one-third of primary Sjögren's syndrome samples, despite the number of CD2+ cells being similar in primary and secondary Sjögren's syndrome and normal PBMC samples. The depressed response to anti-CD2 was mainly found in anti-Ro+/La+ patients. Experiments on purified T cells demonstrated that a defect at the T cell level was responsible for the anti-CD2 unresponsiveness. Cell proliferation failure was associated with poor IL-2 and IL-2 receptor mRNA expression and, consequently, IL-2 and IL-2 receptor synthesis. Since defective anti-CD2-induced mitogenesis could be reversed by phorbol myristate acetate, but not calcium ionophore A23187, it is probably correlated with impaired protein kinase C activation. Comparison of anti-CD2-triggered PBMC proliferation in treated and untreated patients and a long-term study of nine patients showed that the defect is a stable characteristic in primary Sjögren's syndrome patients, but that it can be reversed by pharmacological immunosuppression.

Adrenal Cortex Hormones↗