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Biomedical subjects

M De Carli

Publications and source records attributed to M De Carli.

At least 19 recordsLinked to original sources
PubMed1999

Phenotype and cytokine profile of Schistosoma mansoni specific T cell lines and clones derived from schistosomiasis patients with distinct clinical forms.

It is essential to distinguish the role of T lymphocytes on the physiopathology associated to more severe forms of schistosomiasis and on the immunomodulation that evolves in the majority of infected people. In this study, we generated Schistosoma mansoni-specific T cell lines and clones from patients with the acute and chronic (intestinal and hepatosplenic forms) phases of disease, from former ones, and from uninfected individuals sensitized to parasite soluble antigens. T cell lines derived from nontreated acute infected donors were capable of producing IL-4 and IL-5, while cells from treated patients secreted IFN-gamma. Lines from intestinal chronic and antigen-sensitized donors preferentially produced IFN-gamma, while those from hepatosplenic patients secreted all three cytokines. The cytokine analysis of CD4+ T cell clones revealed a Th2/Th0 pattern (clones producing IL-4 and IL-5 and clones producing all three cytokines) for those derived from infected patients, while cells from antigen-sensitized donors exhibited an opposite Th1/Th0 pattern (clones producing IFN-gamma and clones producing all three cytokines). The possible role of these T cell populations on human schistosomiasis mansoni is discussed.

Acute Disease↗
PubMed1998

Human Th1 and Th2 T-cell clones are equally susceptible to infection and immortalization by human T-lymphotropic virus type I.

Human CD4+ Th1 and Th2 clones were infected with human T-lymphotropic virus type I (HTLV-I) and followed up for a 12 month period in culture. PCR analysis showed that proviral DNA and viral mRNA were present in both Th1 and Th2 infected clones, throughout the entire culture period. Thus, HTLV-I exhibited neither preferential tropism nor exerted differential immortalizing activity in Th1 versus Th2 cells. All the infected clones immediately lost their antigen dependency for growth and continuously proliferated in IL-2-conditioned medium without need for additional stimulation. Infected Th1 and Th2 clones equally showed high expression of CD25, HLA-DR, CD44, CD30 and CD45RO. Infection with HTLV-I altered the cytokine profile in Th1 and Th2 clones. Both types of clones produced IL-6 and TNF-alpha. Th1 infected clones retained their ability to secrete IFN-gamma, but lost IL-2 gene expression. Th2 infected clones lost IL-4 gene expression, retained the ability to produce small amounts of IL-5 and acquired IFN-gamma expression.

Antigens, CD↗
PubMed1997

T helper 1 effector cells specific for Helicobacter pylori in the gastric antrum of patients with peptic ulcer disease.

Chronic antral gastritis following Helicobacter pylori (Hp) infection is characterized by a cellular inflammatory infiltrate whose cytokines may represent a host-dependent factor influencing the outcome of the infection. The pattern of cytokines produced by the immunologically active cells in the gastric antrum was analyzed at the mRNA level in antral biopsies from five Hp-infected patients with duodenal ulcer and three Hp-negative dyspeptic controls. T cell clones were generated from parallel antral biopsies of the same Hp-infected patients and assessed for reactivity to Hp Ags, cytokine profile, and effector functions. Antral biopsies from all Hp-infected patients showed IFN-gamma, TNF-alpha, and IL-12, but not IL-4, mRNA expression, whereas no cytokine mRNA signal was found in the mucosa of controls. A total of 24 out of the 163 CD4+ T cell clones (15%) derived from Hp-infected patients proliferated in response to a Hp lysate; 11 clones (46%) also reacted with Cag-A, 2 with Vac-A, and 1 with urease. Upon Ag stimulation, 20 out of the 24 Hp-reactive clones (83%) produced IFN-gamma, but not IL-4 or IL-5 (Th1-like), whereas 4 produced IFN-gamma, IL-4, and IL-5 (Th0-like). All Hp-specific clones secreted high levels of TNF-alpha. At low T:B cell ratio, Hp-specific clones expressed Ag-dependent helper function for B cell proliferation and Ig production, whereas at higher T:B cell ratios, 15 Th1 and 2 Th0 clones lysed Ag-pulsed autologous EBV-transformed B cells. Results provide evidence for Hp-specific Th1 effectors in the gastric antrum of Hp-infected patients, where they may play a role in the genesis of either peptic ulcer or Hp-associated gastric B cell lymphoma.

Adult↗
PubMed1997

Different cytokine profiles of intraphepatic T cells in chronic hepatitis B and hepatitis C virus infections.

BACKGROUND & AIMS: The cytokine pattern secreted by T cells at the site of viral replication may influence the final outcome of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. The aim of this study was to assess whether a cytokine imbalance oriented toward T helper (Th) 1 or Th2-type responses may play a role in chronic hepatitis B or C. METHODS: Production of interferon (IFN)-gamma, interleukin (IL)-4, and IL-5 by wide series of T-cell clones derived from the liver of 6 patients with chronic hepatitis B (291 clones) and 9 patients with chronic hepatitis C (260 clones) was studied. T-cell clones were generated by limiting dilution from freshly isolated mononuclear cells derived from liver tissue to give a reliable representation of the intrahepatic inflammatory infiltrates. RESULTS: The majority of liver-infiltrating T cells in chronic hepatitis C were Th1 cells able to secrete IFN-gamma but unable to secrete IL-4 or IL-5, whereas in hepatitis B, most CD4+ and CD8+ liver T cells were ThO-like cells able to produce not only IFN-gamma but also IL-4 and IL-5. CONCLUSIONS: The different cytokine profiles of T cells within the liver in chronic HBV and HCV infections illustrate a different behavior of the local immune response in these two infections that may have pathogenetic implications.

Adult↗
PubMed1997

Human CD4+ T cell clones produce and release nerve growth factor and express high-affinity nerve growth factor receptors.

BACKGROUND: Increasing evidence shows that nerve growth factor (NGF) plays a role in the complex and fascinating linkage between the nervous and the immune systems due to its ability to modulate functions of several inflammatory cells. OBJECTIVE: To investigate NGF receptor expression and NGF production and release by human CD4+ cells clones, which have primary relevance in modulating inflammatory events through their different subsets of functional phenotypes. METHODS: The expression of NGF and a transmembrane tyrosine kinase (TrkA) was evaluated by immunohistochemistry and flow cytometry analysis in five T(H0), six T(H1), and five T(H2) cell clones derived from human circulating mononuclear blood cells. Moreover, the amount of NGF protein was assessed by measuring the NGF levels in culture supernatants of the T cell clones before stimulation and 48 hours after phytohemagglutinin (PHA) activation by use of an immunoenzymatic assay. RESULTS: Our data have shown that in unstimulated conditions, human CD4+ T cell clones express both immunoreactivity for NGF and the TrkA NGF receptor irrespective of their cytokine profile. Moreover, T(H1) and T(H2) clones, but not T(H0) clones, secrete NGF in basal conditions. PHA activation induces NGF secretion in T(H0) clones and a significant increase of NGF levels in T(H2) (p < 0.05), but not in T(H1) culture supernatants. CONCLUSIONS: Results obtained represent the first evidence of TrkA expression and NGF production and release in human CD4+ cell clones and suggest a possible functional role of NGF in modulating the immune and inflammatory network.

CD4-Positive T-Lymphocytes↗
PubMed1997

Interleukin 4 stimulates infection and temporary growth of human neonatal lymphocytes exposed in vitro to human T-lymphotropic virus type I, but fails to substitute for interleukin 2 in the immortalization of infected cultures.

It has been shown that interleukin 4 (IL-4) stimulates the proliferation of cells from patients affected by adult T-cell leukaemia, the haematological malignancy aetiologically associated with human T-lymphotropic virus type I (HTLV-I). In the present study, human neonatal lymphocytes were exposed to HTLV-I in vitro in the presence of IL-4. The results showed that: (i) cultures exposed to HTLV-I in the presence of either IL-4 or IL-2 bound IL-4; (ii) IL-4 did not substitute for IL-2 as a growth factor in cell lines previously infected and maintained in IL-2; (iii) cultures exposed to HTLV-I and maintained in IL-4 or IL-2 became infected; and (iv) IL-4 sustained the growth of HTLV-I-infected cultures for a maximum of 14 weeks. Moreover, HTLV-I-infected cultures grown in IL-4 showed upregulation of the IL-4 message and lower expression of HLA-DR and CD25 when compared with counterpart cultures maintained in IL-2. These results suggest that continuous growth of T-lymphocytes induced in vitro by HTLV-I infection, at least temporarily, requires signals specifically provided by IL-2 and not by IL-4.

Cell Division↗
PubMed1997

In vivo relevance of CD30 in atopic dermatitis.

CD30 expression was evaluated by immunohistochemistry in lesional skin biopsies of eight patients with active atopic dermatitis (AD) and three patients with allergic contact (nickel-induced) dermatitis (ACD). CD30 expression was also assessed in a large panel of CD4+ and CD8+ T-cell clones generated from the skin biopsies of four patients with AD. Finally, the levels of soluble CD30 (sCD30) were measured in the serum of 41 patients with AD, 19 patients with ACD, and 60 healthy controls. In all specimens of lesional AD skin, where the great majority of infiltrating cells were CD4+ T cells, remarkable numbers of cells were CD30+, whereas virtually no CD30+ cells were found in the skin of patients with ACD. In CD4+ T-cell clones generated from the lesional AD skin, most of which produced both interleukin (IL)-4 and interferon-gamma (IFN-gamma) (Th0-like cells) or IL-4 and IL-5, but not IFN-gamma (Th2-like cells), CD30 expression directly correlated with the ability to produce IL-4 and IL-5, but was inversely related to IFN-gamma production. High levels of sCD30 (correlated with disease activity: r = 0.618) were detected in the serum of most AD patients, whereas there was no increase of sCD30 levels in the serum of patients with ACD. These data support the view that Th0/Th2-type responses predominate in the skin of patients with AD and suggest that the presence of CD30+ T cells in tissues and/or increased levels of sCD30 in biologic fluids are indicative of Th2-dominated responses.

Adult↗
PubMed1996

CD30 cell expression and abnormal soluble CD30 serum accumulation in Omenn's syndrome: evidence for a T helper 2-mediated condition.

Omenn's syndrome (OS) is a severe immunodeficiency, characterized by clinical and laboratory features reminiscent of a T helper type-2 (Th2) response. CD30, a member of the tumor necrosis factor receptor superfamily, has been found to be preferentially expressed by human T cell clones exhibiting a Th2-line profile and function. We investigated whether there are derangement in CD30 expression in tissues, and/or abnormalities in soluble CD30 (sCD30) levels in the serum, or both, of three children with OS and one child with maternal engraftment and Omenn's-like syndrome (OLS). Large proportions of tissue-infiltrating T lymphocytes from all four patients expressed CD30, whereas in control tissues, including peripheral blood, CD30+ T lymphocytes were extremely few or absent. In addition, levels of sCD30 were abnormally increased in all patients' sera. T cell clones were generated from sorted CD30+ and CD30-peripheral blood T cells of the patient with OLS who showed unusually high numbers of circulating CD30+ T lymphocytes. Most CD4+ T cell clones derived from CD30+ cells showed a Th2-like cytokine profile, whereas the majority of clones generated from CD30-T cells were Th1. These findings support the hypothesis that Th2 cells are involved in the pathogenesis of OS. Moreover, they provide evidence that detection of CD30+ T cells in tissues, increased levels of sCD30 in biological fluids, or both, reflect the presence of immune responses characterized by prevalent activation of T cells producing Th2 cytokines.

Cytokines↗
PubMed1995

CD30-mediated signaling promotes the development of human T helper type 2-like T cells.

We have recently shown that CD30, a member of the tumor necrosis factor/nerve growth factor receptor superfamily, is preferentially expressed by human T cell clones producing T helper (Th) type 2 cytokines. We report here that costimulation with an agonistic anti-CD30 monoclonal antibody enhanced antigen (Ag)-induced proliferation and cytokine secretion by established human Th2 and Th0 clones. Moreover, costimulation of peripheral blood mononuclear cells with the same anti-CD30 monoclonal antibody resulted in the preferential development of Ag-specific T cell lines and clones showing a Th2-like profile of cytokine secretion. In contrast, early blockade in bulk culture of CD30 ligand-CD30 interaction shifted the development of Ag-specific T cells towards the opposite (Th1-like) phenotype. Taken together, these data suggest that CD30 triggering of activated Th cells by CD30 ligand-expressing Ag-presenting cells may represent an important costimulatory signaling for the development of Th2-type responses.

Antigen-Presenting Cells↗
PubMed1995

Th1 and Th2 T-helper cells exert opposite regulatory effects on procoagulant activity and tissue factor production by human monocytes.

The role of T-cell subsets in the induction of tissue factor (TF) production by human monocytes in vitro was investigated. Mitogen stimulation enabled both unfractionated T cells and their CD4+ or CD8+ subsets to promote procoagulant activity (PCA). After mitogen or antigen activation, all seven T-cell clones with Th1 cytokine profile, but none of seven Th2 clones, induced TF production and PCA. T-cell blasts from four Th1 activated clones were fixed with paraformaldehyde and added to monocytes in the presence of medium alone or their supernatants. Addition of either fixed Th1 cells or their supernatants induced low TF production (0.2 to 0.6 ng/mL), whereas addition of both resulted in much higher TF synthesis (1.8 to 3.4 ng/mL). Among Th1-type cytokines, only interferon-gamma (IFN-gamma) induced minimal TF production (0.1 to 0.4 ng/mL). No TF synthesis was induced by activated and fixed Th2 cells and/or their supernatants, whereas combined addition of fixed Th2 cells and Th1 supernatants or IFN-gamma induced noticeable TF production. The addition of either anti-IFN-gamma antibody or Th2 supernatants to monocytes stimulated with activated and fixed Th1 cells plus their supernatant resulted in a dose-dependent inhibition of TF synthesis, which was partially restored by neutralization of interleukin-4 (IL-4) or IL-10. Addition of recombinant IL-4, IL-13, or IL-10, but not IL-5, inhibited the Th1-induced TF production by monocytes. Data indicate that both CD8+ and CD4+ Th1, but not Th2, T cells can help TF production and PCA. Both cell-to-cell contact with activated T cells and Th1-type cytokines, in particular IFN-gamma, are required for optimal TF synthesis, whereas Th2-derived cytokines (IL-4, IL-13, and IL-10) are inhibitory. This may be of potential interest for future therapeutic strategies.

Antigens↗
PubMed1995

Hepatitis C virus infection of mononuclear cells from peripheral blood and liver infiltrates in chronically infected patients.

The mechanisms underlying chronicity of hepatitis C virus (HCV) infection are poorly understood, but the importance of impaired viral clearance by the immune system has been suggested. The prevalence of HCV infection of peripheral blood mononuclear cells (PBMC) was in investigated in 34 persistently infected patients with anti-HCV (7 with liver cirrhosis, 10 with chronic active hepatitis, 5 with chronic persistent hepatitis, 4 with chronic lobular hepatitis, and 8 healthy carriers) by polymerase chain reaction (PCR). HCV infection of 116 T cell clones derived from liver infiltrating mononuclear cells obtained from 3 patients with chronic liver disease was examined using the same methods. HCV genomic sequences were found in fresh, unstimulated PBMC from 20 patients with cirrhosis, and chronic active and persistent hepatitis, but in none of the healthy carriers and only in mitogen-activated cells from 1 out of 4 patients with autoresolving chronic lobular hepatitis. Active PBMC infection was confirmed by identification of anti-genomic HCV sequences in the majority of HCV RNA-positive cells (fresh or mitogen-stimulated). A high percentage of T cell clones obtained from liver infiltrates were found to be infected by HCV. These findings suggest that HCV infection of lymphatic cells plays a role in the pathogenesis of chronically evolving liver damage. PBMC may represent a reservoir for latent infection and a site for viral multiplication.

Alanine Transaminase↗
PubMed1995

No relationship between skin-infiltrating TH2-like cells and allergen-specific IgE response in atopic dermatitis.

More than 500 CD4+ T-cell clones (TCCs) derived from the skin of eight patients with atopic dermatitis (AD), two patients with nonatopic dermatologic disorders, two patients with allergic rhinitis, and one healthy nonatopic donor were analyzed for both their pattern of cytokine production and their antigen specificity. The proportions of TCCs from patients with AD producing interleukin-4 in response to stimulation with phorbol 12-myristate 13-acetate plus anti-CD3 antibody were higher, whereas the proportions of interferon-gamma--producing TCCs were lower than those of control subjects. In two patients with AD, the majority of TCCs had a TH2/TH0-like phenotype, whereas in six patients with AD a TH1/TH0-like phenotype was prevalent. TCCs with a TH2/TH0-like phenotype were also isolated from the healthy skin of two patients with allergic rhinitis and one nonatopic donor. In contrast, no TH2-like TCCs were derived from the skin of the two patients with dermatologic disorders of nonallergic origin. No unambiguous correlations was found between the proportions of TCCs producing interleukin-4 or interferon-gamma (or of TCCs with TH2- or TH1-like profile) and the level of total serum IgE, suggesting that CD4+ T cells infiltrating the atopic skin do not play a major role in the production of serum IgE antibodies. When TCCs from five patients with AD were examined for their specificity, the proportions of allergen-specific (Dermatophagoides pteronyssinus and Lol p 1) clones were consistently 6% or lower even in patients with high titers of ryegrassor D. pteronyssinus-specific IgE antibodies. Because similar percentages of allergen-specific TCCs were found in skin from two healthy control subjects, the role of aeroallergens in favoring and maintaining skin lesions in patients with AD remains unclear.

Adolescent↗
PubMed1995

Preferential expression of CD30 by human CD4+ T cells producing Th2-type cytokines.

A large panel of human CD4+ T helper (Th) cell clones with established Th1, Th2, or Th0 profiles of cytokine secretion were examined for the expression of CD30, a member of the tumor necrosis factor receptor superfamily. Th1 clones expressed poor or no CD30 mRNA, and showed low or undetectable expression of both membrane and soluble CD30 (sCD30) protein, whereas Th2 clones showed both CD30 mRNA and membrane CD30 and released substantial amounts of sCD30. Th0 clones exhibited an intermediate pattern of CD30 expression and release. When T cells from the same donor were stimulated with three different antigens (purified protein derivative, PPD; Toxocara canis excretory/secretory antigen, TES; Lolium perenne group I, Lol p I), production of high concentrations of IFN-gamma, but not expression of CD30 or production of IL-4 and IL-5, were observed at any time after stimulation with PPD. In contrast, both CD30 expression and production of IL-4 and IL-5, but not of IFN-gamma, were concomitantly detectable in TES- and Lol p I-reactive T cells, suggesting a temporal relationship between CD30 expression and beginning of Th2-type cytokine production. Finally, CD4+CD30+ T cells specific for Lol p I and inducible to production of Th2-type cytokines were sorted out from the circulation of grass-sensitive patients in concomitance with the onset of allergic symptoms during the seasonal exposure to grass pollen. Thus, CD30 expression appears to be associated with the differentiation/activation pathway of human T cells producing Th2-type cytokines.

Allergens↗
PubMed1994

Polyclonal B cell activation induced by herpesvirus saimiri-transformed human CD4+ T cell clones. Role for membrane TNF-alpha/TNF-alpha receptors and CD2/CD58 interactions.

We have shown that in vitro infection herpesvirus saimiri (HVS) can transform human CD4+ T cell clones with defined Th1 or Th2 cytokine profiles to continuous growth. We report here that transformation with HVS enabled both Th1 and Th2 clones to stimulate proliferation and Ig production by autologous or allogeneic B cells in the absence of stimulants. The polyclonal B cell-activating property of HVS-transformed clones was not related to free virus or soluble cytokines, but rather was dependent on an Ag-nonspecific, MHC-unrestricted, contact-dependent mechanism. T blasts from unstimulated HVS-transformed clones did not express CD40 ligand (CD40L) mRNA or CD40L protein, whereas a proportion of them constitutively expressed membrane TNF (mTNF)-alpha. Both CD40L and mTNF-alpha were detectable on either uninfected or HVS-transformed clones upon mitogen stimulation. The activation of high-density B cells by unstimulated HVS-transformed clones was not inhibited by soluble CD40-Ig fusion protein, but was strongly reduced by either anti-TNF-alpha or anti-TNF-alpha receptor (TNF-alpha R) mAbs. Addition of anti-CD2 and/or anti-CD58 mAbs was also inhibitory, but no additive effect with anti-TNF-alpha and/or anti-TNF-alpha R mAbs was observed. Neither anti-IL-2 nor CD40-Ig inhibited the proliferation of naive IgD+ B cells cocultured with fixed unstimulated HVS-transformed clones, whereas a combination of anti-TNF-alpha and anti-TNF-alpha R mAbs was inhibitory. In addition, fixed unstimulated HVS-transformed clones induced Ig synthesis in IgD+ naive B cells even in the absence of exogenous IL-2. Data suggest that both the mTNF-alpha/TNF-alpha R and the CD2/CD58 pathways, but not the CD40L-CD40 interaction plus secreted cytokines, are involved in the unusual mode of B cell activation exerted by CD4+ HVS-transformed clones.

Antibodies, Monoclonal↗
PubMed1994

Natural variants of cytotoxic epitopes are T-cell receptor antagonists for antiviral cytotoxic T cells.

It has been suggested that mutations within immunodominant cytotoxic T-lymphocyte (CTL) epitopes may be exploited by viruses to evade protective immune responses critical for clearance. Viral escape could originate from passive mechanisms, such as mutations within crucial CTL epitopes, either affecting major histocompatibility complex binding or T-cell antigen receptor (TCR) recognition. Additionally, it has recently been shown that substitutions of TCR contact sites can yield analogue peptides that can still interact with the T-cell receptor but be unable to deliver a full stimulatory signal, thus inducing anergy or acting as an antagonist for the TCR. We report here that hepatitis B virus isolates derived from two chronically infected patients display variant epitopes that act as natural TCR antagonists with the capacity to inhibit the CTL response to the wild-type epitope. During natural infection, TCR antagonist mutations of CTL epitopes could contribute to the development of viral persistence, especially if the antiviral CTL response is monospecific or the epitope is strongly immunodominant.

Amino Acid Sequence↗
PubMed1994

Role of TH1/TH2 cytokines in HIV infection.

Different experimental approaches were used to prove or disprove the "TH1/TH2 switch theory" of HIV-infection. No increase, or even a decrease, in the production of TH2-type cytokines (IL-4, IL-5, and IL-10) by either bulk circulating mononuclear cells or CD4+ T-cell clones generated by PHA stimulation of single T cells from HIV-infected individuals in all stages of disease compared to HIV-negative donors was observed. However, enhanced proportions of CD4+ T-cell clones able to produce both TH1-type and TH2-type cytokines (TH0 clones) were derived from either skin-infiltrating, in vivo-activated, T cells or in vitro antigen-stimulated peripheral blood T cells of HIV-infected individuals. Of note, TH1, TH2 and TH0 clones obtained from HIV-seronegative healthy donors showed different ability to support viral replication after infection with HIV in vitro. All TH2 and most TH0 clones supported HIV replication efficiently, whereas TH1 clones did not. These results suggest preferential HIV replication in T cells producing TH2-type cytokines rather than TH1/TH2 switch in HIV infection.

Animals↗