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Biomedical subjects

C Tassinari

Publications and source records attributed to C Tassinari.

13 recordsLinked to original sources
PubMed1998

Impaired cytokine production by neutrophils isolated from patients with AIDS.

OBJECTIVES: To determine the ability of neutrophils isolated from HIV-seropositive patients to produce proinflammatory cytokines. DESIGN: The in vitro responsiveness of polymorphonuclear neutrophils (PMN) and peripheral blood mononuclear cells (PBMC) to lipopolysaccharide (LPS), used in the presence or absence of interferon (IFN)gamma, was determined in 47 HIV-positive patients with advanced stages of virus infection. METHODS: Cytokines in cell-free supernatants were measured by enzyme-linked immunosorbent assay or radioimmunoassay. RESULTS: Cell-free supernatants from PMN isolated from the peripheral blood of HIV-positive patients and stimulated with LPS contained increased amounts of tumour necrosis factor (TNF)-alpha and interleukin (IL)-8 with respect to supernatants obtained from PMN of normal donors. In contrast, release of IL-1beta and IL-1ra (IL-1 receptor antagonist) in response to LPS, or LPS plus IFNgamma, was found to be lower in PMN from HIV-positive patients than in PMN from controls, but was significant only in the case of IL-1ra. Furthermore, the release of IL-12 induced by LPS or LPS plus IFNgamma did not significantly differ between PMN from HIV-positive patients and healthy donors. Concerning PBMC, the production of TNF-alpha and IL-12 in response to LPS, or LPS plus IFNgamma, was found to be significantly higher in cells isolated from HIV-positive patients, whereas the release of IL-1beta was significantly lower. In the case of IL-8, no statistically significant difference was found between PBMC isolated from HIV-positive patients and healthy donors. CONCLUSIONS: Collectively, the data suggest that in HIV-positive patients with advanced stages of disease, the ability of PMN to produce specific cytokines in response to LPS is significantly altered. Alterations in this ability might contribute to the evolution of HIV disease.

Adolescent↗
PubMed1997

Interleukin-15 triggers activation and growth of the CD8 T-cell pool in extravascular tissues of patients with acquired immunodeficiency syndrome.

The impairment of interleukin-2 (IL-2) production occurs very early after human immunodeficiency virus (HIV) infection as a consequence of the quantitative depletion of Th1 cells. Despite the shift in cytokine production, most individuals develop an oligoclonal expansion of major histocompatibility complex restricted, HIV-specific CD8+ cytotoxic T lymphocytes (CTL) in different organs, suggesting that other cytokines replace IL-2 in initiating the tissue infiltration of CD8+ T cells. In this study we show that IL-15, a product of monocyte-macrophages and non-T cells and which has overlapping biological activities with IL-2, is involved in local cell networks accounting for the activation and expansion of CD8+ T-cell pools in a highly affected organ, ie, the lung. IL-15 induced proliferation of T cells obtained from the lower respiratory tract of HIV-infected patients with T-cell alveolitis and severe depletion of CD4+ T cells. Lung lymphocytes were CD45R0+/CD8+ T cells spontaneously expressing activation markers (CD69 and HLA-DR) and equipped with the receptorial subunits which bind IL-15, notably the beta and gamma chains of the IL-2 receptor (IL-2R) and the recently identified IL-15 binding-protein termed IL-15R alpha. Similar phenotypic findings were obtained after incubation of normal T cells with IL-15, which induced CD8+ T cells to express activation markers and to proliferate. The block of the IL-2R beta/IL-2R gamma complex with specific monoclonal antibodies abolished the T-cell stimulatory activity of IL-15 while the combination of IL-15 and tumor necrosis factor-alpha upregulated the proliferative response of lung T lymphocytes. The hypothesis that the tissue growth of lung CD8+ lymphocytes may involve cytokines produced from cells other than T lymphocytes was confirmed by the evidence that pulmonary macrophages expressed high levels of IL-15 and that anti-IL-15 antibodies inhibited the accessory function of alveolar macrophages on mitogen-induced CD8+ T-cell proliferation. Together, these results suggest that macrophage-derived cytokines produced at sites of T-cell infiltration play a role in the activation of HIV-specific CD8+ T-cell-mediated immune response.

AIDS-Related Opportunistic Infections↗
PubMed1997

Interleukin-15 triggers the proliferation and cytotoxicity of granular lymphocytes in patients with lymphoproliferative disease of granular lymphocytes.

The recently cloned cytokine interleukin-15 (IL-15) shares several functional activities with IL-2 in different cell systems. Although IL-15 does not show sequence homology with IL-2, it uses components of the IL-2 receptor (IL-2R) for binding and signal transduction, namely, p75 (beta) and the p64 (gamma) chains of IL-2R. To evaluate whether IL-15 is involved in the activation of granular lymphocytes (GL) in patients with lymphoproliferative disease of granular lymphocytes (LDGL), we evaluated the ability of IL-15 to stimulate GL proliferation, cytotoxic function, and the role of IL-2R beta and gamma molecules on relevant cells. Our results show that IL-15 stimulates cell proliferation and cytotoxic activity of GL in LDGL patients. Reverse-transcriptase polymerase chain reaction (RT-PCR) and phenotypic analyses using the anti-IL-2R gamma-chain-specific TUGh4 monoclonal antibody (MoAb) indicate that both CD3+ and CD3- GL express the p64 IL-2R, a result previously unknown. IL-15 activity was inhibited by antibodies against p75 and p64 IL-2R chains, while no inhibitory effects are detectable with anti-p55 IL-2R antibody. The association of anti-p75 and anti-p64 IL-2R MoAbs resulted in a nearly complete (95%) inhibition of IL-15-induced GL proliferation. Using RT-PCR analysis, we demonstrated that highly purified CD3+ and CD3- GL did not express mRNA for IL-15 or IL-2. By contrast, a clear-cut IL-15 mRNA signal was detected by RT-PCR in patients' peripheral blood mononuclear cells, with monocytes likely accounting for the source of IL-15 in LDGL patients. However, even in concentrated supernatants from enriched monocyte populations, we could not demonstrate the presence of IL-15 protein. Using anti-IL-15 specific MoAbs, a membrane-bound form of this cytokine was demonstrated both on CD3+ and CD3- LDGL cells. By RT-PCR analysis, purified GL from these patients were found to express the message for IL-15 receptor alpha chain. Taken together, these results indicate that both CD3+ and CD3- GL are stimulated by IL-15 and that this cytokine mediates its activity through the beta and gamma chains of the IL-2R, providing further suggestions for the interpretation of the mechanisms that lead to cell expansion in patients with LDGL.

Adult↗
PubMed1997

Selection of T lymphocytes bearing limited TCR-Vbeta regions in the lung of hypersensitivity pneumonitis and sarcoidosis.

Hypersensitivity pneumonitis (HP) and sarcoidosis are interstitial lung disorders (ILD) characterized by a lymphocytic alveolitis that, in the active phase of the disease, is sustained by different T-cell subsets, i.e., CD8+ cells in HP and CD4+ lymphocytes in sarcoid patients. To address the question of whether a bias in T-cell selection occurs in the lung of patients with HP and sarcoidosis, we analyzed the T-cell receptor beta chain variable region (TCR-Vbeta) repertoire by flow cytometry and polymerase chain reaction (PCR) analyses in blood and lung lymphocytes of 14 HP and 25 sarcoid patients. To verify whether these cells can be activated in vitro through the TCR, blood and lung lymphocytes were also assessed for their responsiveness to different superantigenic stimuli represented by staphylococcal enterotoxins, including SEA, SEB, SEC1, SEC2, SED, and SEE. Flow cytometry and PCR analyses demonstrated an overexpression of cells bearing Vbeta2, Vbeta3, Vbeta5, Vbeta6, and Vbeta8 gene segments in the lung of HP patients as compared with the peripheral blood. In sarcoid patients cells bearing Vbeta2, Vbeta5, and Vbeta6 gene segments in the lung of HP patients as compared with the peripheral blood. In sarcoid patients cells bearing Vbeta2, Vbeta5, and Vbeta6 gene segments were overrepresented in the lung rather than in the blood. Both in HP and sarcoid patients almost all T cells bearing the dominant Vbeta segment belonged to the T-cell subset that sustains the alveolitis, i.e., CD8 in HP patients and CD4 in sarcoid subjects. Follow-up studies demonstrated that the recovery of the alveolitis was characterized by the disappearance of cells bearing a limited T-cell repertoire. Interestingly, T-lymphocyte response to different superantigens demonstrated that the proliferation elicited by different staphylococcal toxins was more pronounced in the lung than in the blood. Taken together, our findings indicate a compartmentalization of cells bearing discrete Vbeta gene products in the pulmonary microenvironment and suggest that the expansion of specific Vbeta region subsets occurring in the lung might result from triggering by a specific antigen. In fact, the removal from exposure in HP patients or specific treatment in sarcoidosis resulted in the decrease of the overrepresented cell population accounting for the lymphocytic alveolitis.

Adult↗
PubMed1996

The CD5/CD72 receptor system is coexpressed with several functionally relevant counterstructures on human B cells and delivers a critical signaling activity.

The CD5 molecule is expressed on T cells and, at a lower density, on a minor B cell subset (CD5+ B cells). The pan-B Ag CD72 was recently identified as the CD5 counterstructure, and several data suggest the involvement of this ligand pair in T-B cell cognate interaction. However, the functional role of CD5 and CD72 molecules within the B cell compartment is still unknown. In this work we studied umbilical cord blood CD5+ B cells (B-1a), adult splenic CD5- B cells (B-2), and CD5+ B cells from patients with chronic lymphocytic leukemia. Flow cytometry analysis and proliferation assays were used to determine 1) the ability of B-1a and B-2 cells to coexpress functionally relevant counterligands other than CD5 and CD72, and 2) the signaling capacity of CD5 and CD72 in terms of B cell activation and proliferation. To this purpose, freshly isolated or preactivated normal and neoplastic B cells were cultured with agonistic anti-CD5 or anti-CD72 mAbs in the presence or the absence of cytokines equipped with B cell activity. Our data demonstrate that CD5 and CD72 molecules are coexpressed with other ligand pairs usually involved in T-B cell cognate interaction on B-1a cells, but not on B-2 cells. CD5 and/or CD72 engagement delivers critical costimulatory signals in B-1a, B-2, and B cells from patients with chronic lymphocytic leukemia, but with different requirements and patterns. Besides suggesting the potential involvement of B-1a lymphocytes in B-B cell interactions during T-independent B cell responses, our results indicate that CD5 and CD72 counterstructures play a functional role in the B cell compartment.

Adult↗
PubMed1996

Role of IL-15, IL-2, and their receptors in the development of T cell alveolitis in pulmonary sarcoidosis.

Recent data suggest that the newly discovered cytokine IL-15 cooperates with IL-2 in driving T cell-mediated immune responses. The aim of this study was to determine the role of IL-15 in the regulatory networks leading to the development of T cell alveolitis in the lung of patients with sarcoidosis. We demonstrated that alveolar macrophages (AMs) isolated from the bronchoalveolar lavage of patients with active sarcoidosis expressed IL-15 mRNA and membrane and cytoplasmic IL-15, while AMs from healthy subjects and patients with inactive sarcoidosis did not. Pulmonary CD4+ T cells from sarcoid patients were equipped with the IL-2R subunits, which are able to bind IL-15, i.e., the IL-2R beta/IL-2R gamma complex, and proliferated in response to IL-15. Interestingly, the T cell proliferation elicited by IL-15 was comparable with that determined by IL-2. Following the addition of graded amounts of IL-15, IL-2-pulsed T cells showed a significant increase in their stimulation. TNF-alpha up-regulated the IL-15-mediated proliferative response of bronchoalveolar lavage T lymphocytes. Following the block of the IL-2R beta- and gamma-chains with specific mAbs, the stimulatory activity of IL-15 was abolished. The evaluation of the IL-2R on sarcoid AMs demonstrated the constitutive expression of alpha- and gamma-chain mRNA and proteins. Taken together, these findings demonstrate that IL-15 triggers the growth of sarcoid T cells through the IL-2R beta/IL-2R-gamma complex and raise the possibility that AMs may deliver proliferative signals for the development of the T cell alveolitis. Modulation of IL-2R on AMs could represent a critical variable in regulating local inflammatory responses.

Adult↗
PubMed1996

Interleukin-15 promotes the growth of leukemic cells of patients with B-cell chronic lymphoproliferative disorders.

The recently discovered cytokine, interleukin-15 (IL-15), has been demonstrated to share several biologic properties with IL-2 in different cell systems, including T-cell and natural killer (NK) cell compartments. As for B lymphocytes, IL-15 has been shown to provide stimulatory activities in normal preactivated B cells that are mainly transduced through IL- 2 receptor (IL-2R) complex components. Since leukemic B cells from patients with chronic lymphoproliferative disorders (CLD) bear IL-2R and grow in response to IL-2, we investigated whether IL-15 triggers the proliferation of malignant B cells obtained from 12 patients with B-cell chronic lymphocytic leukemia (B-CLL) and five patients with hairy cell leukemia (HCL). Enriched B cells recovered from five healthy subjects were also studied as controls. IL-15 stimulated the proliferation of freshly isolated leukemic B cells, but not resting normal B lymphocytes, the latter being able to grow in the presence of IL-15 only after in vitro preactivation with phorbol myristate acetate. The proliferation elicited by IL-2 on leukemic cells was comparable to that determined by IL-15. Following addition of graded concentrations of IL-15 to low/intermediate-dose IL-2, resting leukemic B cells showed a higher stimulatory rate than that observed using the two cytokines separately. In normal resting B lymphocytes, this cumulative effect was not observed. The role of different IL-2R subunits in IL-15-driven growth of malignant B cells was investigated both by their expression on leukemic cells and by the block of different IL-2R subunits (p55, p75, and p64) with specific monoclonal antibodies (MoAbs). Using flow cytometry and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses we demonstrated that both B-CLL and HCL leukemic B cells express the beta and gamma chains of the IL-2R system. The stimulatory activity achieved by IL-15 decreased significantly, blocking the beta and gamma chains of the IL-2R. Taken together, these findings demonstrate that IL-15 triggers the growth of leukemic B cells through IL-2R system subunits, pointing to the role of this novel cytokine in regulating the neoplastic proliferation in CLD.

Adult↗
PubMed1996

Skewing of the T-cell receptor repertoire in the lung of patients with HIV-1 infection.

OBJECTIVES: A bias of the use of T-cell receptor (TCR) V beta regions has been reported both in peripheral blood and in several tissues in patients with AIDS, including lymph nodes, spleen and salivary glands. Although the disease is frequently characterized by an infiltration of T cells in the lung interstitium, no information is presently available on the configuration of the TCR repertoire in this microenvironment. This study was performed to address the question of whether a bias in T-cell selection occurs in the lung of patients with AIDS. METHODS: TCR beta-chain variable region (TCR-V beta) repertoire was analysed by flow cytometry and polymerase chain reaction (PCR) analyses in blood and lung lymphocytes of 13 patients with HIV-1 infection at different stages of the disease. Blood and lung lymphocytes were also assessed for their responsiveness to different superantigenic stimuli represented by staphylococcal enterotoxins (SEA, SEB, SEC1, SEC2, SED and SEE). RESULTS: Flow cytometry analysis in AIDS patients demonstrated an overexpression of cells bearing V beta 2 and V beta 3 gene segments in the lung compared with peripheral blood of the same subjects, as well as to lung and blood lymphocytes of normal controls. PCR analysis performed in AIDS patients extended these observations and demonstrated a significant bias also in the use of T cells bearing V beta 7 and V beta 9 gene regions in the lung compartment with respect to the blood. Virtually all T cells bearing the overrepresented V beta segment belong to the CD8 subset. Interestingly, T-lymphocyte response to different superantigens demonstrated a low proliferative rate in the lung with respect to the blood in HIV-1-infected patients. CONCLUSIONS: These findings indicate a compartmentalization of cells bearing discrete V beta gene products in the pulmonary microenvironment of patients with AIDS and suggest that the expansion of specific-V beta region subsets occurring in the lung might result from triggering by a superantigen.

Adult↗
PubMed1996

Expression of tumor necrosis factor-receptor superfamily members by lung T lymphocytes in interstitial lung disease.

Recently, a novel receptor superfamily has been identified whose members interact with a parallel family of ligands showing homology to tumor necrosis factor (TNF). To investigate the role of these receptor structures in the pulmonary environment, we evaluated the expression of some members of the TNF-receptor (CD27, CD30, CD40, CD95/Fas, CD120a, and CD120b) and TNF-ligand (CD40L, CD70/CD27L, CD30L, and mTNFalpha) superfamilies by bronchoalveolar lavage (BAL) T cells recovered from healthy subjects and patients with interstitial lung disease (ILD). Lung T lymphocytes recovered from control subjects showed a slight expression of CD27 but did not bear CD30, CD40, CD120a, or CD120b antigens. CD27 expression was restricted to normal CD4+ cells. Fas antigen (CD95), which is involved in activation-driven T-cell suicide, and the ligand for CD27 (CD70) were weakly expressed by normal BAL T-cell subpopulations. In patients with sarcoidosis, the majority of pulmonary T lymphocytes were CD4+ cells that expressed low levels of CD27 antigen and an upregulation of CD95 and CD70 molecules. When we characterized lymphocytes accumulating in the lung of patients with HIV infection and hypersensitivity pneumonitis, we demonstrated that T cells accounting for the CD8 alveolitis bore TNF-receptor type 2 (CD120b) at high density and were CD70+ while CD40L, CD30L, or mTNF-alpha expression were not found. The discrete surface expression of the TNF-receptors and TNF-ligands on alveolar T-cell subsets suggests that these molecules play a role in the immune regulatory mechanisms that ultimately lead to the alveolitis in the pulmonary microenvironment of interstitial lung disease.

Adult↗
PubMed1996

Lung lymphocytes: origin, biological functions, and laboratory techniques for their study in immune-mediated pulmonary disorders.

Different types of immunocompetent cells, including T lymphocytes and alveolar macrophages, account for pulmonary host defense. Taking advantage of the availability of the monoclonal antibody technique, cell culture facilities, pure recombinant cytokines, and molecular probes for their genes, in the last few years it has been possible to keenly study the different steps that lead to the compartmentalization of immune response in human lung. Furthermore, the immunological analysis of cells retrieved from bronchoalveolar lavage (BAL) allowed recognition of the importance of immune mechanisms in the evolution of immune-mediated pulmonary disorders. The purpose of this review is to summarize recent advances on the immunologic characterization of lung lymphocytes in health and disease. Following a brief description of the pathways through which the pulmonary lymphoid system contributes to removing potentially harmful inhaled antigenic materials, available laboratory techniques to evaluate the lymphoid component of the pulmonary immune system and their byproducts are discussed. These techniques cover methods for preparing lymphocytes from the BAL fluid and for characterizing lung lymphocytes both in cell suspensions and pulmonary tissue biopsies. Other sections of this review describe the techniques for measuring the immunologic effector functions of lung lymphocytes. We also provide the reader with a flavor of the molecular biology methods used to characterize lymphocytes in the pulmonary microenvironment. The final sections of the review article highlight the pathogenetic role envisaged for lymphoid cells in pulmonary disease states and emphasize the importance of the BAL analysis in the clinical management of the most relevant immune-mediated lung disease.

Animals↗
PubMed1995

Analysis of the T cell receptor in the lymphoproliferative disease of granular lymphocytes: superantigen activation of clonal CD3+ granular lymphocytes.

To investigate whether cell populations in CD3+ lymphoproliferative disease of granular lymphocytes (LDGLs) were skewed toward the use of specific V beta regions, we studied the repertoire of T-cell receptor (TCR) V beta gene products in 18 patients, as well as their relationship to the clonal bands in the Southern blot and the activation mediated by superantigens. Using a panel of monoclonal antibodies (mAbs) for conserved V beta segments and PCR, a dominant population expressing a specific V beta region was demonstrated in all patients. In five (27%) cases, granular lymphocytes (GLs) were found to express the V beta 13.1, while V beta 8 and V beta 6 were each expressed in three (17%) cases. The remaining cases were characterized by the proliferation of TCR V beta 2, V beta 3, V beta 4, V beta 9, V beta 12, V beta 16, and V beta 20. This finding indicates a biased usage of a limited TCR V beta in LDGLs, since nearly 60% of the cases utilized only three families of the TCR V beta genes. In all of the cases studied, we proved that the subset recognized by mAb and PCR was identical to that accounting for the extra band(s) of the Southern blot. This finding confirms the clonal nature of the population identified according to TCR V beta expression both by phenotype and PCR. On functional grounds, we evaluated whether GLs can be activated through the specific TCR using the superantigens recognizing discrete V beta families, such as staphylococcal proteins, including SEA, SEB, SEC1, SEC2, SED, and SEE. We demonstrated that the TCR-alpha/beta of clonal GLs in LDGL patients is functionally active in delivering cytotoxic and proliferative signals upon superantigen activation.

CD3 Complex↗