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G Filaci

Publications and source records attributed to G Filaci.

31 records · Page 2Linked to original sources
PubMed1996

Prednisone increases apoptosis in in vitro activated human peripheral blood T lymphocytes.

Glucocorticoid hormones (GCH) regulate, through the apoptotic process, the negative selection of immature T cells in the thymus. Because apoptosis seems to occur also in the maintenance of peripheral tolerance, we have investigated whether GCH may induce apoptosis in human mature lymphocytes. Peripheral blood lymphocytes (PBL) or peripheral CD4(+) and CD8(+) T cell subsets were cultured in the presence of phytohaemaglutinin (PHA) or PHA and prednisone (PDN) at 10(-3)-10(-12)M concentrations for 72, 96 and 120h. Cell cycle and membrane antigen expression were evaluated by flow cytometry and DNA degradation was detected by agarose gel electrophoresis. PDN blocks PBL growth in the G1 phase of cell cycle and inhibits both IL-2 receptor (IL-2R) expression and IL-2 secretion. Apoptosis is clearly increased by PDN in PHA-activated human PBL, and the apoptotic effect of PDN is stronger on CD8(+) than on CD4(+) T lymphocytes. All these effects are dose- and time-dependent. The addition of exogenous IL-2 did not rescue lymphocytes from PDN-increased apoptosis. These results show that PDN increases apoptosis in mature activated human peripheral blood lymphocytes, suggesting a possible role of GCH in the maintenance of immune tolerance at post-thymic level.

Adult↗
PubMed1995

Major histocompatibility complex class I-restricted presentation of influenza virus nucleoprotein peptide by B lymphoma cells harboring an antibody gene antigenized with the virus peptide.

We analyzed the capacity of B cells to process and present a peptide from the variable region of an endogenous immunoglobulin heavy (H) chain to a major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocyte (CTL) clone. The H-chain gene was engineered to express 14-amino acid peptide from the sequence of the influenza virus nucleoprotein (NP) antigen in the third complementarity-determining region (CDR3). This NP peptide is presented in association with the Db allele in H-2b mice. We demonstrate that B lymphoma cells (H-2b) harboring the antigenized H-chain gene process and present the NP peptide in association with the Db molecule and are lysed by a CTL clone specific for that peptide in an MHC-restricted way. In contrast, the soluble antigenized antibody failed to mediate lysis of H-2b target cells. The endogenously processed immunoglobulin CDR3 peptide could be eluted from surface Db molecules in transfected cells. This study formally demonstrates that peptides from the hypervariable loops of endogenous immunoglobulin are processed through the endogenous degradative pathway and are presented to CD8+ T cells in the context of MHC class I molecules. The implication of these findings for processing and presentation of endogenous immunoglobulin peptides in B cells and network regulation by idiopeptides is discussed.

Amino Acid Sequence↗
PubMed1995

CD4+ Th0 cell clones, isolated from a metastatic lymph node of a melanoma patient, possess cytolytic function.

In the present study T lymphocytes isolated from a metastatic lymph node (T-LNL) of a melanoma patient have been cloned. In the attempt to verify whether T-LNL may acquire in vitro functional activities in the absence of tumour-associated antigens, they were cloned utilizing allogenic lymphocytes as feeder cells. Nineteen clones generated from T-LNL proved to be CD4+ and, among these, five were able to kill autologous and allogeneic human melanoma cells in HLA-class-II-restricted way. On the basis of their cytokine production, these CD4+ cytolytic T-LNL clones were shown to belong to the Th0 subset and three of them expressed the V beta 17 chain of the T cell receptor. These results suggest the presence of melanoma-specific but functionally inactive lymphocytes with T cell receptor oligoclonality in the lymph node environment. These specific T cells may acquire in vitro the capacity to kill autologous and allogeneic tumours without any induction by autologous melanoma cells.

CD4-Positive T-Lymphocytes↗
PubMed1995

Interferons up-regulate with different potency HLA class I antigen expression in M14 human melanoma cell line. Possible interaction with glucocorticoid hormones.

The relative potency of interferon alpha (IFN alpha), interferon beta (IFN beta), and interferon gamma (IFN gamma) in inducing the expression of HLA class I antigens, as well as their capacity to counteract the inhibition induced by glucocorticoid hormones on HLA class I antigen expression, were analysed in the human melanoma cell line M14, both at membrane and at mRNA level. The data obtained indicate that (a) IFN enhance with different potency (IFN gamma > IFN beta > IFN alpha) the expression of HLA class I antigens in M14 cells, (b) prednisone inhibits HLA class I antigen expression, (c) glucocorticoid hormones, when associated with IFN alpha or IFN gamma, inhibit the HLA class I enhancement induced by IFN alone, and, finally, (c) the association between 1 microM prednisone or 1 microM deflazacort and IFN beta seems to potentiate the enhancing capacity of IFN on the expression of HLA class I molecules at the mRNA level. These findings, if confirmed, might indicate that IFN and glucocorticoid hormones are not mutually exclusive in the management of human melanoma.

Drug Synergism↗
PubMed1995

Increased serum concentration of soluble HLA-DR antigens in HIV infection and following transplantation.

HLA class I and class II antigens circulate in serum as soluble molecules. Increased concentrations of soluble HLA class I molecules have been demonstrated in viral diseases, in rejection episodes following organ transplantation and in graft versus host disease. To explore the possibility of a variation of the serum concentrations of soluble HLA class II molecules in the same pathologic conditions we developed a double determinant immune assay that detects whole soluble HLA-DR molecules (sHLA-DR). The mean level of sHLA-DR antigens in sera from 23 healthy individuals was 0.64 +/- 0.72 microgram/ml. Elevated serum concentrations of sHLA-DR molecules were detected in sera from HIV infected patients in CDC2/3 and in CDC4 C1 stages (2.0 +/- 1.7 micrograms/ml and 4.6 +/- 1.7 micrograms/ml, respectively), in sera from patients affected by acute rejection after liver transplantation (5.3 +/- 3.7 micrograms/ml) and in sera from patients affected by severe acute graft versus host disease following bone marrow transplantation (8.8 +/- 3.1 micrograms/ml). The increase of sHLA-DR molecules in these sera significantly correlated with the elevation of soluble HLA class I antigens (P = 0.0004). The reported data suggest that both soluble HLA class I and class II molecules serum levels increase during viral infections and strong immune reactions and could suggest the involvement of these molecules in immunoregulation.

Bone Marrow Transplantation↗
PubMed1994

Immune cell circulating subsets are affected by gonadal function.

Influence on the immune system activity by sex hormones has been widely reported. Fertile women are proner to the onset of autoimmune diseases than men, but this increased susceptibility disappears after menopause. The hormonal changes are very likely to be responsible for this event, but precise correlations between sex hormone levels and immune functions have not been defined. For this reason we have analyzed phenotype and natural cytotoxicity of peripheral blood lymphocytes (PBL) from 35 women in menopause, comparing them with the same parameters of 28 fertile and 8 postmenopausal women and correlating them with the hormonal pattern of each group. We have also considered 8 women with premature menopause. Hormonal levels have been detected by radioimmune assays, while PBL phenotype has been studied by immunofluorescence and FACS analysis. The natural killer (NK) cell activity has been calculated on the basis of a chromium release assay. Postmenopausal women showed a reduction of the number of total lymphocytes (1650 +/- 215 cells/mmc) in comparison to fertile women (2081 +/- 200 cells/mmc, P < 0.01). The decrease mainly involved B and CD4+ T lymphocyte subpopulations (P < 0.05 and P < 0.01, respectively). Women with premature menopause had lower percentage of CD4 lymphocytes (34% vs 47%, P < 0.01) and higher percentage of CD8 (30% vs 22%, P < 0.02) and NK cells (32% vs 14%, P < 0.009) than fertile women of the same age. The percentage of circulating lymphocytes expressing HLA class II antigens also resulted as being increased (22% vs 9%, P < 0.01). The number of total, CD2, CD4 T lymphocytes, B and NK cells correlated positively with LH and negatively with FSH serum levels (P < 0.05 and P < 0.002, respectively). PRL positively influenced CD2, CD4 and B lymphocyte numbers (P < 0.001). FSH and 17 beta-estradiol inversely affected CD8 and B lymphocyte numbers (P < 0.005 and P < 0.02, respectively). In conclusion, the increase of FSH and the decrease of PRL levels appear to be involved in the reduction of B and CD4 T lymphocytes thus lowering the risk for the onset of autoimmune diseases during and after menopause. Generalized activation of the immune system (raised expression of HLA class II antigens) with elevated numbers of cytotoxic subpopulations (CD8 and NK lymphocytes) is present in women affected by premature menopause suggesting the involvement of autoimmune dysregulation in the pathogenesis of this syndrome.

Adult↗
PubMed1993

Expression of conformationally constrained adhesion peptide in an antibody CDR loop and inhibition of natural killer cell cytotoxic activity by an antibody antigenized with the RGD motif.

We report that an antibody engineered to express three Arg-Gly-Asp (RGD) repeats in the third complementarity-determining region of the heavy chain (antigenized antibody) efficiently inhibits the lysis of human erythroleukemia K-562 cells by natural killer (NK) cells. Synthetic peptides containing RGD did not inhibit. Inhibition was specific for the (RGD)3-containing loop and required simultaneous occupancy of the Fc receptor (CD16) on effector cells. The antigenized antibody inhibited other forms of cytotoxicity mediated by NK cells but not cytotoxicity mediated by major histocompatibility complex-restricted cytotoxic T lymphocytes (CTL). A three-dimensional model of the engineered antibody loop shows the structure and physicochemical characteristics probably required for the ligand activity. The results indicate that an RGD motif is involved in the productive interaction between NK and target cells. Moreover, they show that peptide expression in the hypervariable loops of an antibody molecule is an efficient procedure for stabilizing oligopeptides within a limited spectrum of tertiary structures. This is a new approach towards imparting ligand properties to antibody molecules and can be used to study the biological function and specificity of short peptide motifs, including those involved in cell adhesion.

Amino Acid Sequence↗
PubMed1993

Immunotherapy with intralesional and systemic interleukin-2 of patients with non-small-cell lung cancer.

Eight patients affected by non-small-cell lung cancer were treated with intralesional and systemic recombinant IL-2 (rIL-2) injection with the aim of activating both tumour-infiltrating lymphocytes and circulating cytotoxic or killer cells. The schedule of treatment was as follows: a daily fine-needle transparietal intralesional rIL-2 injection (1 x 10(5) Cetus units) from day 1 to day 5 and systemic rIL-2 infusion (1 x 10(5) Cetus units kg-1 day-1) from day 6 to day 10. One to four cycles of treatment were received by each patient. Clinical and immunological evaluations were performed (a) before treatment, (b) following the intralesional rIL-2 administration, (c) 1 h after the beginning of rIL-2 infusion and (d) at the end of the systemic rIL-2 infusion. No complete remission was achieved, two patients showed a partial remission, three resulted in stable disease and three patients progressed. Natural killer and lymphokine-activated killer cell activity dramatically decreased 1 h after the beginning of rIL-2 infusion and increased at the end of treatment. A progressive increase of circulating CD8+ and HLA class II+ T cells as well as of CD8+ T cell clones, most of which displayed NK activity, was recorded following rIL-2 infusion. Present data indicate that (a) the local administration of rIL-2 coupled with systemic rIL-2 infusion may be suggested as an alternative approach for the immunotherapy of lung cancer, (b) rIL-2 induces different immunological modifications according to the route and the time of its administration and (c) rIL-2 administration increases the amount of circulating immune cells with potential antitumour activity.

Carcinoma, Non-Small-Cell Lung↗
PubMedDate not supplied

Long-term treatment of patients affected by systemic sclerosis with cyclosporin A.

The aims of the present study were: 1) to verify the tolerability of long-term, low-dose treatment of patients affected by systemic sclerosis with cyclosporin A; 2) to analyze the clinical outcome of treated patients in relationship to skin, esophageal, lung, kidney and microvascular organ involvement. Nine patients affected by diffuse systemic sclerosis were treated for periods ranging from 3 to 5 years with cyclosporin A at a dosage of 2.5 mg/kg/day. Cyclosporin A treatment was variably associated or not with treatments for Raynaud's phenomenon (pentoxiphylline, defibrotide, low-dose heparin, prostacyclin analogues) in relationship to the needs of single patients. We report on patient clinical evaluations performed every year and including plicometry, esophageal pH-manometry, pulmonary spirometry, renal duplex Doppler sonography, echocardiography as well as nailfold videocapillaroscopy. The results of single tests were converted into scores. The existence of statistically significant differences between baseline mean scores and mean scores after 1, 2 and 3 years of therapy was analyzed. All patients tolerated cyclosporin A well, and no definitive withdrawals from the study were observed. Hypertricosis appeared in 3 patients, and 1 patient interrupted treatment for 6 months because of the onset of pneumonitis. No alterations of blood pressure and renal functionality were detected. Statistically significant reduction of all analyzed mean scores was observed after 2 and/or 3 years of cyclosporin A treatment with respect to baseline. The overall results suggest an encouraging clinical effect for low-dose, long-term cyclosporin A treatment in systemic sclerosis. Satisfactory tolerability and clinical improvement were observed in all the patients consecutively treated for at least 3 years.

Adult↗
PubMedDate not supplied

dsDNA-, nucleohistone- and DNASE I-reactive T lymphocytes in patients affected by systemic lupus erythematosus: correlation with clinical disease activity.

OBJECTIVE: To demonstrate the involvement of T lymphocytes reactive to autoantigens in the pathogenesis of autoimmune diseases and to analyse their clinical relevance. METHODS: The frequency of T cell clones reactive to double strand DNA (dsDNA), Nucleohistone (NH) complex and Dnase I was calculated for the peripheral blood mononuclear cells (PBMC) of 15 SLE patients and 9 healthy subjects by proliferation assay. RESULTS: DsDNA- and NH-specific T cell clones were found in the majority of the patients analysed (frequency ranging from 2 to 50 clones/10(7) PBMC), while their absence or very low frequency (2 clones/10(7) PBMC) was observed in the control PBMC. Their frequency significantly correlated with decreased serum concentrations of C3 and C4 and with the systemic lupus erythematosus disease activity index (P = 0.03). A very low frequency of Dnase I-reactive T cell clones was observed in both SLE and healthy subjects. CONCLUSION: Our results suggest that dsDNA- and NH-reactive T lymphocytes may be involved in the pathogenesis of SLE and that their quantification in the peripheral blood of patients could be a useful tool to follow the clinical course of the disease.

Adult↗