Biomedical subjects
Publications and source records attributed to Sergio Romagnani.
We describe the first known case of congenital lymphoedema associated with selective deficit of naïve CD4+ T-lymphocytes. A high proportion of naïve CD4+ T-lymphocytes was found in the ascitic fluid, supporting the hypothesis of extra-vascular sequestration of these cells into lymphoedematous tissue.
CD8+CD25+ cells, which expressed high levels of Foxp3, glucocorticoid-induced tumor necrosis factor receptor (GITR), CCR8, tumor necrosis factor receptor 2 (TNFR2), and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) mRNAs, were identified in the fibrous septa and medullary areas of human thymus. Activated CD8+CD25+ thymocytes did not produce cytokines, but most of them expressed surface CTLA-4 and transforming growth factor beta1 (TGF-beta1). Like CD4+CD25+, CD8+CD25+ thymocytes suppressed the proliferation of autologous CD25-T cells via a contact-dependent mechanism. The suppressive activity of CD8+CD25+ thymocytes was abrogated by a mixture of anti-CTLA-4 and anti-TGF-beta1 antibodies and it was mediated by their ability to inhibit the expression of the interleukin 2 receptor alpha chain on target T cells. These results demonstrate the existence of a subset of human CD8+CD25+ thymocytes sharing phenotype, functional features, and mechanism of action with CD4+CD25+ T regulatory cells.
The chemokines CXCL9/Mig, CXCL10/IP-10, and CXCL11/I-TAC regulate lymphocyte chemotaxis, mediate vascular pericyte proliferation, and act as angiostatic agents, thus inhibiting tumor growth. These multiple activities are apparently mediated by a unique G protein-coupled receptor, termed CXCR3. The chemokine CXCL4/PF4 shares several activities with CXCL9, CXCL10, and CXCL11, including a powerful angiostatic effect, but its specific receptor is still unknown. Here, we describe a distinct, previously unrecognized receptor named CXCR3-B, derived from an alternative splicing of the CXCR3 gene that mediates the angiostatic activity of CXCR3 ligands and also acts as functional receptor for CXCL4. Human microvascular endothelial cell line-1 (HMEC-1), transfected with either the known CXCR3 (renamed CXCR3-A) or CXCR3-B, bound CXCL9, CXCL10, and CXCL11, whereas CXCL4 showed high affinity only for CXCR3-B. Overexpression of CXCR3-A induced an increase of survival, whereas overexpression of CXCR3-B dramatically reduced DNA synthesis and up-regulated apoptotic HMEC-1 death through activation of distinct signal transduction pathways. Remarkably, primary cultures of human microvascular endothelial cells, whose growth is inhibited by CXCL9, CXCL10, CXCL11, and CXCL4, expressed CXCR3-B, but not CXCR3-A. Finally, monoclonal antibodies raised to selectively recognize CXCR3-B reacted with endothelial cells from neoplastic tissues, providing evidence that CXCR3-B is also expressed in vivo and may account for the angiostatic effects of CXC chemokines.
Atherosclerotic lesions are infiltrated by macrophages and T lymphocytes, potentially reactive to pathogens. We studied in vivo activated T lymphocytes that infiltrate atherosclerotic plaques of Helicobacter pylori-infected patients with or without anti-Chlamydia pneumoniae antibodies. In all atherosclerotic lesions, T helper type 1 (Th1) cells were predominant. C. pneumoniae-specific T cells were detected only in the plaques of anti-C. pneumoniae seropositive patients, whereas H. pylori-specific T cells were found in the gastric mucosa but not in the plaques of the same patients. Plaque-derived Th1 cells expressed cytotoxicity, proapoptotic activity, and help for monocyte tissue factor production. Although multifactorial, atherosclerosis can be regarded as a Th1-driven immunopathological condition.
BACKGROUND: In experimental models, imidazoquinolines exhibit several immunomodulatory activities via Toll-like receptor signaling on cells of the innate immunity. OBJECTIVE: The aim of our study was to investigate whether R-848 (Resiquimod), a small-molecular-weight synthetic compound belonging to the imidazoquinoline family and known for its ability to substantially delay the onset of recurrent genital herpes lesions in both animals and human beings, could influence, at least in vitro, the cytokine production profile of human hapten- or allergen-specific T cells. METHODS: Ampicillin- and Der p 1-specific T-cell lines were derived from peripheral blood of allergic donors in the absence or presence of R-848 and assessed by flow cytometry at the single-cell level for their ability to produce IL-4 and/or IFN-gamma. RESULTS: R-848 induced both hapten- and allergen-specific circulating T cells, including T(H)2 effectors, to produce IFN-gamma and even to lose the ability to produce IL-4, thus shifting their phenotype of cytokine production to a type 0 (T(H)0) or even T(H)1 profile. This effect was associated with an increase in the production of IL-12, IFN-alpha, IL-18, TNF-alpha, IL-10, and IL-15 by CD14(+) cells, as well as an increase in the proportions of IFN-gamma-producing CD3(-)CD16(+) (natural killer) cells. CONCLUSIONS: These results suggest that R-848, and probably other imidazoquinolines, might be used as adjuvants in view of novel allergen-specific immunotherapeutic regimens for the treatment of allergic disorders.
Phenotypic markers, localization, functional activities, and mechanisms of action in vitro of CD4(+)CD25(+) T cells, purified from postnatal human thymuses, were investigated. These cells showed poor or no proliferation in mixed lymphocyte culture (MLC), and suppressed in a dose-dependent fashion the proliferative response to allogeneic stimulation of CD4(+)CD25(-) thymocytes. Virtually all CD4(+)CD25(+) thymocytes constitutively expressed cytoplasmic T lymphocyte antigen (CTLA)-4, surface tumor necrosis factor type 2 receptor (TNFR2), and CCR8. They prevalently localized to perivascular areas of fibrous septa and responded to the chemoattractant activity of CCL1/I-309, which was found to be produced by either thymic medullary macrophages or fibrous septa epithelial cells. After polyclonal activation, CD4(+)CD25(+) thymocytes did not produce the cytokines interleukin (IL)-2, IL-4, IL-5, IL-13, interferon gamma, and only a very few produced IL-10, but all they expressed on their surface CTLA-4 and the majority of them also transforming growth factor (TGF)-beta1. The suppressive activity of these cells was contact dependent and associated with the lack of IL-2 receptor (IL-2R) alpha-chain (CD25) expression in target cells. Such a suppressive activity was partially inhibited by either anti-CTLA-4 or anti-TGF-beta1, and was completely blocked by a mixture of these monoclonal antibodies, which were also able to restore in target T cells the expression of IL-2R alpha-chain and, therefore, their responsiveness to IL-2. These data demonstrate that CD4(+)CD25(+) human thymocytes represent a population of regulatory cells that migrate in response to the chemokine CCL1/I-309 and exert their suppressive function via the inhibition of IL-2R alpha-chain in target T cells, induced by the combined activity of CTLA-4 and membrane TGF-beta1.
The cytokine profile of circulating and vaginal T cells specific for immunodominant mannoprotein antigens of Candida albicans was analyzed in patients with recurrent vaginal candidiasis (RVC). Peripheral blood mononuclear cells (PBMC) from patients with RVC proliferated more than those from healthy subjects and expressed higher type 1:type 2 T helper cell cytokine ratios in response to C. albicans stimulation. A higher number of C. albicans-specific T cells was generated in PBMC from patients with RVC than in PBMC from healthy donors. C. albicans-specific T cell clones from patients with RVC produced higher levels of interferon (IFN)-gamma and lower levels of interleukin (IL)-4 than clones from control women. More important, a higher proportion of C. albicans-specific T cell clones was generated from lesional mucosa of patients with RVC than from normal mucosa, all of which produced IFN-gamma but not IL-4. These findings provide direct evidence that RVC is characterized by a highly polarized local and circulating type 1 T helper cell-like response against C. albicans antigens.
Tumor-infiltrating lymphocytes (TILs) from biopsies of 9 selected patients with pT1pN0M0 renal cell carcinoma (RCC) were analyzed at the clonal level for phenotypic distribution, cytokine secretion profile and antitumor cell proliferation and cytotoxicity. T-cell clones generated from RCCs were able to produce higher amounts of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) than the corresponding clones derived from peripheral blood mononuclear cells, thus suggesting a recruitment into tumors of T cells with peculiar functions. Moreover, CD4+ T-cell clones generated from TILs of nuclear grading 2 (G2)-type RCC patients produced significantly higher amounts of IL-4 and IL-10 and lower amounts of IFN-gamma than the corresponding clones generated from G1-type RCC and 2 renal angiomyolipoma (AML) patients. In addition, T-cell clones generated from lymphocytes infiltrating the peritumoral areas of G2-type, but not those from G1-type, RCC patients produced higher and lower amounts of IL-4 and IFN-gamma, respectively, than the corresponding clones derived from intratumoral T cells of the same patients. The proportion of T-cell clones derived from G2-type tumors and proliferating to autologous tumor cells (ATCs) was significantly lower than that of clones generated from G1-type RCC or AML patients. However, irrespective of their source, they exhibited similar cytokine profiles and produced comparable amounts of IL-4, IL-10 and IFN-gamma. Furthermore, the proportion and the production of both IL-4 and IFN-gamma of G2-type RCC-derived T-cell clones with cytotoxic activity against ATC were significantly lower than those of cytolytic clones generated from AML and G1-type RCCs. The concentrations of IL-4, IL-10 and IFN-gamma produced by the cytolytic clones from G2-type RCC were also lower than those produced by their noncytolytic counterparts obtained from the same patients. These data address the association of the nuclear grading of neoplastic cells with different local tumor-specific T-cell responses in RCC.
OBJECTIVE: To characterize the cytokine production profile of male-offspring T cells reactive against maternal major histocompatibility complex (MHC) antigens present in the peripheral blood and/or skin from women with systemic sclerosis (SSc). METHODS: T cell clones were generated from peripheral blood and/or skin biopsy specimens from 3 women with SSc of recent onset and from peripheral blood from 3 healthy women, all of whom had 1 male child. All clones were screened for their proliferative response in vitro to maternal MHC antigens by measuring (3)H-thymidine uptake and for their expression of Y chromosome by using fluorescence in situ hybridization. The concentrations of interferon-gamma and interleukin-4 (IL-4) released by T cell clones in response to maternal MHC antigens were evaluated in culture supernatants, using appropriate enzyme-linked immunosorbent assays. RESULTS: Thirty-nine of 202 T cell clones generated from women with SSc and 11 of 312 from healthy women proliferated in vitro in response to maternal MHC antigens. Seven MHC-reactive T cell clones obtained from women with SSc and 1 obtained from healthy women exhibited the Y chromosome, thus indicating that the clones were derived from T cells of male offspring. All clones generated from male-offspring T cells of SSc women (but not from those of healthy women) produced significantly higher levels of IL-4 in response to stimulation with maternal MHC antigens than did all other clones generated from the same women. The other clones proliferated in response to maternal or allogeneic MHC antigens but did not exhibit the Y chromosome. CONCLUSION: Male-offspring T cells that are present in the blood and skin of women with SSc and react with maternal MHC antigens exhibit a Th2-oriented profile, supporting the possibility that a chronic graft-versus-host reaction attributable to long-term microchimerism plays a pathogenic role in SSc.
Particular attention has been recently dedicated to the development of a sarcoidosis-like form in patients with common variable immunodeficiency (CVI). In sarcoidosis a 5-fold increase in the number of cells in the bronchoalveolar lavage compared with normal controls has been described and the predominance of CD4+ T cells is a common feature. In contrast to patients affected by sarcoidosis or CVI, patients with co-existence of the two diseases had a more favorable prognosis, as progressive pulmonary fibrosis occurred only in a few cases even when persistent alveolar lymphocytosis was present. Moreover, patients presenting with concomitant sarcoidosis and CVI, showed a lower rate of respiratory infections and of the evolution towards bronchiectasies in comparison with patients affected by CVI alone. The clinical evolution observed in our patients was similar with that reported in other studies and confirms their clinical features. One may speculate that the increase in the number of macrophages and T lymphocytes, as suggested by the increased cellularity in the bronchoalveolar lavage of these patients, can produce a peculiar microenvironment characterized by high levels of soluble factors (cytokines). In turn, the latter could be responsible for a more efficacious effector phase of the immune response. This may explain the reduced rate of infectious diseases and consequently of bronchiectasies observed in CVI patients.