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Biomedical subjects

G F Del Prete

Publications and source records attributed to G F Del Prete.

At least 55 records · Page 3Linked to original sources
PubMed1982

In vitro production of IgE by human peripheral blood mononuclear cells. IV. Modulation by allergen of the spontaneous IgE antibody biosynthesis.

Peripheral blood lymphocytes (PBL) from a proportion of grass-sensitive patients, studied during or immediately after the grass pollination period, showed spontaneous production in vitro of grass-specific IgE antibody, whereas PBL from atopic patients sensitive to allergens other than grass pollens or non-atopic individuals did not. Pre-incubation of IgE antibody producing PBL from grass-sensitive patients with minute amounts of a mixed grass pollen (MGP) extract or Rye grass antigen Group I (Rye I) usually resulted in a reduction of the spontaneous production in vitro of IgE protein and in a marked inhibition of the spontaneous production in vitro of grass-specific IgE antibody. This antigen-specific inhibition was not mediated by T lymphocytes, but it was apparently due to a signal directly delivered by antigen to the spontaneously IgE antibody producing cells. The results support the concept that the activity of cells responsible for the persistent IgE antibody formation in vitro in atopic patients can be modulated by antigen.

Antibody Specificity↗
PubMed1980

T-cell independence of immunoglobulin synthesis by human peripheral blood lymphocytes stimulated with SpA-containing staphylococci.

Unfractionated and T-cell depleted human peripheral blood lymphocytes (PBL) were cultured in vitro in the presence of pokeweed mitogen (PWM) and Staphylococcus aureus strain Cowan I (StaCw). After 7 days of culture, the cells were assayed for cytoplasmic immunoglobulins (Cyto-Ig) by direct staining using fluorescein-labelled F(ab')2 fragments prepared from specific antisera against human IgG F(ab')2. The amount of immunoglobulin of the IgM and IgG class released into the cell-free supernatants was also measured by radioimmunoassay. In unfractionated PBL StaCw, like PWM, was able to induce a significant increase of either the number of Cyto-Ig containing cells for the amount of IgM and IgG secreted into the supernatant. In contrast, the amount of IgM and IgG immunoglobulin released into the supernatant of T-cell depleted suspensions stimulated with PWM was significantly reduced in comparison with that of unfractionated populations, whereas it was unchanged in T-cell depleted vs unfractionated suspensions stimulated with StaCw. The addition of a few T lymphocytes restored the ability of T-cell depleted suspensions to produce Ig in the presence of PWM, whereas despite addition of high numbers of T cells no further augmentation of the Ig production induced by StaCw on T-cell depleted suspensions was observed. Cultures of umbilical cord blood lymphocytes (UCBL) stimulated with PWM did not generate Ig-producing cells, whereas UCBL stimulated with StaCw showed significant production of Ig of both IgM and IgG classes. The results indicate that T lymphocytes are probably not involved either with stimulation or with the suppression of Ig production induced by StaCw.

Adult↗
PubMed1979

A simple solid-phase radioimmunoassay for the measurement of IgG secreted in vitro by human lymphocytes.

A radioimmunoassay is described for measuring IgG, based on the ability of immunoglobulins of this class to inhibit the binding of radioiodinated staphylococcal protein A to IgG linked to a solid phase. The solid phase is represented by ox erythrocytes coated with anti-ox erythrocyte rabbit IgG, a reagent used for detecting cells equipped with receptors for the Fc fragment of IgG. By this assay the IgG secreted in vitro by human peripheral blood lymphocytes stimulated with PWM and those present in samples of very diluted human sera were measured. It was found that the assay is a very rapid, simple and reproducible procedure for the detection of IgG immunoglobulin at the nanogram level.

Animals↗
PubMed1979

Circulating antibodies in malignant melanoma patients.

Sera from 46 patients with malignant melanoma (MM) in different clinical stages and from 25 healthy blood donors were studied by an indirect conventional immunofluorescent technique (IIT) and by an immunofluorescent complement-fixation test (ICFT). No specific and reliable serological reactivity could be demonstrated against autologous and homologous MM and other nonmalignant pigmented tissues. An increased incidence of diffused antinuclear (ANA; 41%) and cytoplasmic epidermal cell autoantibodies (A-CYT; 71%) was observed in the patients by IIT. Statistical evaluation of the results gave significant values in the chi 2 test in patients for ANA (chi 2 = 5.2061; p less than 0.05) and for A-CYT (chi 2 = 8.9176; p less than 0.01) versus age-matched controls. Thyroid microsomal, gastric parietal cell, smooth muscle and mitochondria autoantibodies were, respectively, detected in 4.3, 4.3, 4.3 and 0% of patients' sera.

Antibodies, Neoplasm↗
PubMed1977

Insulin and glucagon secretion in diabetic and non-diabetic patients with circulating islet cell antibodies.

Thirty-nine patients (14 non-diabetics, 8 chemical diabetics, and 17 overt diabetics) with circulating islet cell antibodies (ICA) were studied. Insulin and glucagon secretion after oral (100 g) and intravenous glucose loading (200 mg/kg bolus injection followed by an infusion of 20 mg/min over 60 min) and arginine infusion (25 g over 30 minutes) were evaluated in these patients and in non diabetic and diabetic ICA-negative controls. In the non-diabetic groups with or without ICA, insulin and glucagon responses to glucose were similar. Moreover, in ICA positive patients the response of these hormones to arginine infusion was reduced. Similar alterations in insulin and glucagon secretion were observed in the CIA positive and negative patients with chemical or overt diabetes. In particular, fasting hyperglucagonaemia and glucagon hyperresponse to arginine are associated with a lack of insulin secretion in the patients with overt diabetes. Hormonal differences between diabetics with and without ICA could not be detected.

Adult↗
PubMed1977

Clotting factors and platelets. Immunofluorescence evidence that fibrinogen and factor VIII are present in human washed platelets, whereas prothrombin complex factors and factor XIII are lacking.

Factor I (fibrinogen) and factor VIII were shown, by an indirect immunofluorescence technique, to be present in human washed platelets. In the case of fibrinogen, the immunofluorescent pattern had a 'clod distribution' up to a 1:128 dilution of the antiserum. Factor VIII showed a 'speckled' pattern up to the 1:64 dilution. Cross-absorption studies confirmed the presence of such factors. Factor II, VII, IX, X and XIII, however, were not found in washed platelets. A diffuse fluorescence was noted using normal rabbit sera, but this was due to a cross-reaction, since it disappeared using a 1:32 diluted sera.

Animals↗
PubMed1976

Heterologous specificity of reticulin RS antibodies.

Reticulin antibodies were detected by the indirect immunofluorescence technique in 1450 sera from miscellaneous patients. R1 pattern on human and rat tissues was found only in 2 cases with adult coeliac disease. Reticulin Rs staining, involving intrasinusoidal cells of rat liver as well as interstitial and endothelial structures of various rat tissues, was demonstrated in 3.7% of cases, without correlation with gastro-intestinal or skin disorders. Rs pattern, due to IgG antibodies, could be absorbed by rat erythrocytes. Only Rs positive sera showed high titres of anti-rat IgG-type hemoagglutinins. Rat RBC agglutinating activity was demonstrated by a modified indirect Coomb's test. Heterologous Rs antibodies appear unrelated to particular diseases and should not be mistaken for the R1 and R2 patterns, which may be useful for diagnostic procedures.

Animals↗
PubMed1976

Isoantibodies to human exocrine pancreas and endothelium.

A cytoplasmic immunofluorescence of some human pancreatic exocrine cells was obtained in 19.2% of 270 patient undiluted sera and confirmed in 20.4% of 98 healthy controls. No relation was found with clinical disorders or autoantibodies. This reaction was always associated with human endothelial antibodies and both were clearly related to high titre "incomplete" IgG anti-A group isoagglutinins.

Endothelium↗
PubMedDate not supplied

Role of interleukin-4 in the induction of human IgE synthesis and its suppression by interferon-gamma.

Supernatants (SN) from 10 phytohemagglutinin (PHA)-stimulated human T cell clones (TCC), selected for their helper function on IgE synthesis, were found to provide IgE helper activity in atopic B cells showing low or undetectable spontaneous in vitro IgE synthesis. In contrast, SN from 5 PHA-stimulated TCC unable to provide helper function for IgE synthesis consistently failed to elicit IgE production. SN active on IgE synthesis contained high concentrations of interleukin-4 (IL-4), whereas inactive SN did not contain detectable amounts of IL-4. Moreover, the IgE helper activity of TCC SN was strongly inhibited by the addition of interferon-gamma (IFN-gamma) to B cell cultures. These data suggest that IL-4 may play a role in the induction of in vitro human IgE synthesis, whereas IFN-gamma displays an inhibitory effect.

B-Lymphocytes↗
PubMedDate not supplied

An update on human Th1 and Th2 cells.

The existence of functionally polarized human T cell responses based on their profile of cytokine secretion in both the CD4+ T helper (Th) and the CD8+ T cytotoxic cell subset has been established. Human Th1 and Th2 cells not only produce a different set of cytokines but also exhibit distinct functional properties and preferential expression of some activation markers, such as LAG-3 and CD30, respectively. Several factors are involved in the Th cell differentiation into the polarized Th1 or Th2 pathway. They include the cytokine profile of 'natural immunity' evoked by different offending agents, the nature of the peptide ligand, as well as the activity of some costimulatory molecules and microenvironmentally secreted hormones, in the context of different host genetic backgrounds. Polarized Th1-type and Th2-type responses play different roles in protection, Th1 being effective in the defense against intracellular pathogens and Th2 against intestinal nematodes. Moreover, they are responsible for different types of immunopathological reactions. Th1 responses predominate in organ-specific autoimmune disorders, acute allograft rejection, unexplained recurrent abortions, and in some chronic inflammatory disorders of unknown etiology. In contrast, Th2 responses predominate in Omenn's syndrome, transplantation tolerance, chronic graft versus host disease, systemic sclerosis; moreover allergen-reactive Th2 cells are involved in the triggering of atopic disorders.

Autoimmune Diseases↗