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V Barnaba

Publications and source records attributed to V Barnaba.

83 records · Page 5Linked to original sources
PubMedDate not supplied

Expression of class I and class II major histocompatibility complex antigens on human hepatocytes.

We analyzed whether normal human hepatocytes, which normally do not display Class II major histocompatibility complex antigens, can be induced to express them in vitro, and whether this induction has an in vivo counterpart in chronic liver diseases. While both alpha- and gamma-interferon induced expression of Class I antigens, only gamma-interferon induced expression of Class II antigens on hepatocytes in vitro. Recombinant interleukin 2 had no effect on major histocompatibility complex antigen expression. Both Class I and Class II antigens could be detected by indirect immunofluorescence on hepatocytes from patients with various forms of chronic liver disease, regardless of etiology. These findings suggest that gamma-interferon produced by T lymphocytes that infiltrate the liver during the course of chronic hepatitis induces Class II major histocompatibility complex antigen expression and may endow the hepatocytes with the capacity to perform accessory (antigen-presenting) cell functions.

Antibodies, Monoclonal↗
PubMedDate not supplied

Interleukin-6 production by human hepatoma lines is related to a low degree of cell differentiation.

In this study, we showed by Northern blot analysis and bioassays that scarcely differentiated human hepatoma cell line HA22T/VGH constitutively produces interleukin-6 (IL6). This cytokine was produced neither by moderately differentiated Li7A nor by well-differentiated HepG2 human hepatoma cell lines. The finding that transcripts for IL6 were not present in 2.2.15 cells, a HepG2-derived clone transfected with the intracellular replicative form of hepatitis B virus (HBV) DNA, suggests that production of this cytokine is not affected by HBV-encoded gene products, but is more likely related to the dedifferentiated state of hepatoma cells.

Biological Assay↗
PubMedDate not supplied

[Phenotypic and functional characterization of cloned T-lymphocytes from cerebrospinal fluid of patients with multiple sclerosis].

T cell clones derived from the cerebrospinal fluid of patients with multiple sclerosis were investigated for their ability to produce IL2, IL4, IFN gamma and TNF alpha. As controls, liver infiltrating T lymphocyte clones from patients with chronic active hepatitis were used. All CSF clones (both CD4+ and CD8+) produced high amounts of IFN gamma and particularly of TNF alpha. TNF was synthesized in a significantly higher amount than control clones. Moreover, they were capable of secreting IL2 but not IL4. From our results we conclude that CSF-CD4+ T clones could constitute a subset with functional properties similar to those of the Th1/inflammatory cells of the mouse. The unusually high amount of TNF produced by CSF derived T cell clones strongly suggests a significant role for this cytokine in MS immunopathogenesis.

Adult↗
PubMedDate not supplied

Autoimmune chronic liver disease as a model of human autoimmunity.

Although clonal deletion and clonal energy have been demonstrated in transgenic mice, the findings that autoreactive B or T cells are present in healthy subjects suggest that they are not the sole mechanisms of tolerance. As regards helper T lymphocytes, tolerance to self-antigens can arise by preventing class II MHC expression on non-lymphoid cells and autoantigen presentation to helper T cells initiating the autoimmune response. Autoimmune chronic active hepatitis (CAH) seems to be a good model of self-tolerance bypass. Hepatocytes are able to express class II molecules and can perform accessory cell functions with respect to T cell clones generated from lymphocytes infiltrating the liver in autoimmune CAH patients. The class II antigen expression on hepatocytes may be modulated by IFN-gamma released by infiltrating T lymphocytes; thus, the activated liver cells can present autoantigens to autoreactive T cell clones. On the other hand, these findings may occur only when the upregulation of IFN-gamma or other lymphokines permits the expression of rare class II antigens on hepatocytes capable of binding particular residues of a liver-autoantigen which are recognized by specific autoreactive T cell clones binding different residues on the same epitope.

Autoimmune Diseases↗
PubMedDate not supplied

Class II MHC antigen expression on epithelial cells of salivary glands from patients with Sjögren's syndrome.

Class II MHC molecules are two-chain glycoproteins normally expressed only on the membrane of cells involved in the immune response. These molecules are restriction elements for helper T cells. Using indirect immunofluorescence on cryostat sections of biopsied salivary glands we have demonstrated epithelial expression of class II antigens in patients with Sjögren's syndrome. The HLA DR+ epithelial cells were seen in close proximity to lymphocyte infiltrates. The finding that class II molecules are also expressed in salivary glands without focal lymphocytic infiltrates suggests a "modulation" as opposed to "induction" of HLA DR antigens on epithelial cells in Sjögren's syndrome, the distinction being related to the enhancement of low levels of expressions vs. de novo synthesis.

Adult↗
PubMedDate not supplied

Neuroendocrinoimmunology.

Interest in neuroendocrinoimmunology has increased greatly in the last decade. The most important evidence of neuroendocrine-immune system interactions is that spleen, thymus, bone marrow and lymph nodes are innervated by neurons of the autonomic nervous system; changes in brain functions can affect different immune responses; immune and neuroendocrine cells share receptors (e.g., lymphocytes and macrophages have receptors for a vast number of hormones and neuropeptides); hormones and neuropeptides can alter the functional activity of immune system cells; several hormones and neuropeptides can be synthesized by leukocytes; cytokines produced by leukocytes are able to modulate neuroendocrine system activity, behaviour, sleep and thermoregulation. The recent literature on neuroendocrinoimmunology has laid the physiopathological groundwork for a new clinical approach which perceives and treats the patient as a psychic and somatic whole.

Autonomic Nervous System↗
PubMedDate not supplied

Human hepatoma cells expressing HLA class I molecules stimulate primary responses of purified CD8+ T lymphocytes.

In the present study, we investigated the ability of major histocompatibility complex (MHC) class-I+ human hepatoma cell lines to induce primary proliferative responses of purified allogeneic CD8+ T lymphocytes. We found that HA22T/VGH and Li7A, but not HepG2 cells induced significant proliferation of CD8+ T cells and that these responses were dependent on class I molecule expression. In blocking experiments carried out to identify the costimulatory signals involved, we found that anti-ICAM1 monoclonal antibodies drastically inhibited CD8+ T-cell proliferative responses. These findings suggest that transformed hepatocytes expressing HLA class I molecules may participate in anti-tumour immunosurveillance by the direct induction of cytotoxic T-cell responses through ICAM1-mediated adhesive interaction.

Antibodies, Monoclonal↗