Search results for "Lymphocyte"
showing 10 items of 2280 documents
HBV-specific immune defect in chronic hepatitis B (CHB) is correlated with a dysregulation of pro- and anti-inflammatory cytokines.
1999
SUMMARY The aim of this study was to examine the immunomodulating effects of rhIL-12 on the immune response induced by hepatitis B virus (HBV) antigens in clinical subgroups of patients with HBV infection. Peripheral blood mononuclear cells (PBMC) of 80 patients were stimulated with HBsAg, HBcAg, pre-S1Ag and tetanus toxoid in the absence or presence of IL-12 (0.01, 0.1 and 1 ng/ml). Stimulation by anti-CD3 + anti-CD28 and lipopolysaccharide (LPS) were used as controls. Proliferation and cytokine production were determined by 3H-thymidine uptake and ELISA after 72 h. After stimulation with HBV antigens only, production of tumour necrosis factor-alpha (TNF-α) or IL-10 was observed in all pat…
Fine-mapping of the B-cell epitope domain at the N-terminus of the preS2 region of the hepatitis B surface antigen
2002
In this study, we report the exact localization and substitutional characterization of a B-cell epitope domain at the N-terminus of the preS2 region of the hepatitis B surface antigen. A set of deletion variants containing preS2 sequences of different length was generated on the basis of frCP as a carrier. It was found after Western blot analysis that three monoclonal antibodies (MAbs) (2-11B1, 3-11C2, HB.OT10) recognized the linear preS2 sequence within the amino acid (aa) stretch 3-WNSTTFHQTLQDP-13. The importance of each aa residue of the epitope was proved by comparison of antibody binding to alanine-substituted peptides in both free-peptide and Pepscan variants.
Seasonal features of lymphocyte extravasation through bthe lymph nodal HEVS
2008
Quantification of CD8+ T lymphocytes responsive to human immunodeficiency virus (HIV) peptide antigens in HIV-infected patients and seronegative pers…
1998
/ T cells responding to HIV-1 peptides were observed in none of 11 HIV- seronegative donors without a history of HIV exposure. ELISPOT assays are relatively fast and easy to perform and appear to reliably detect T cell reactivity due to previous exposure to HIV. These findings support the use of the ELISPOT assay for monitoring T cell responsiveness to HIV peptides. In acute infection with the human immunodeficiency virus We described recently an enzyme-linked immunospot (ELISPOT) assay to detect and quantitate single blood-de- type 1 (HIV-1), initial reduction in virus load is associated with the appearance of a high frequency of antiviral cytotoxic T rived CD8 / T lymphocytes forming tumo…
Consensus guidelines for the detection of immunogenic cell death
2014
Apoptotic cells have long been considered as intrinsically tolerogenic or unable to elicit immune responses specific for dead cell-associated antigens. However, multiple stimuli can trigger a functionally peculiar type of apoptotic demise that does not go unnoticed by the adaptive arm of the immune system, which we named "immunogenic cell death" (ICD). ICD is preceded or accompanied by the emission of a series of immunostimulatory damage-associated molecular patterns (DAMPs) in a precise spatiotemporal configuration. Several anticancer agents that have been successfully employed in the clinic for decades, including various chemotherapeutics and radiotherapy, can elicit ICD. Moreover, defect…
Isolation of HTLV III/LAV from drug addicts in Palermo.
1987
The new human retroviruses HTLV III/LAV, implicated as the causative agent of AIDS, have been isolated from peripheral blood lymphocytes of 5 of 13 drugs abusers with acquired immunodeficiency syndrome-related complex (ARC). In one patient the virus was also found in cell-free plasma. No HTLV III/LAV was detected in or isolated from 5 clinically healthy drug abusers. The lymphocytes were cultured with interleukin 2 and expressed either a transcriptase reverse activity or HTLV III/LAV antigens within 2-3 weeks of cultivation. The viruses were also transmitted into normal lymphocytes from cord blood of human newborns. At the present state of development, virological investigation, other than …
Immune activation promotes evolutionary conservation of T-cell epitopes in HIV-1.
2013
The immune system should constitute a strong selective pressure promoting viral genetic diversity and evolution. However, HIV shows lower sequence variability at T-cell epitopes than elsewhere in the genome, in contrast with other human RNA viruses. Here, we propose that epitope conservation is a consequence of the particular interactions established between HIV and the immune system. On one hand, epitope recognition triggers an anti-HIV response mediated by cytotoxic T-lymphocytes (CTLs), but on the other hand, activation of CD4(+) helper T lymphocytes (TH cells) promotes HIV replication. Mathematical modeling of these opposite selective forces revealed that selection at the intrapatient l…
Behavior of a Short preS1 Epitope on the Surface of Hepatitis B Core Particles
1999
The major immunodominant region of hepatitis B core particles is widely recognized as the most prospective target for the insertion of foreign epitopes, ensuring their maximal antigenicity and immunogenicity. This region was mapped around amino acid residues 79-81, which were shown by electron cryo-microscopy to be located on the tips of the spikes protruding from the surface of hepatitis B core shells. Here we tried to expose a model sequence, the short immunodominant hepatitis B preS1 epitope 31-DPAFR-35, onto the tip of the spike, with simultaneous deletion of varying stretches from the major immunodominant region of the HBc molecule. Accessibility to the monoclonal anti-preS1 antibody M…
EGF and HGF levels are increased during active HBV infection and enhance survival signaling through extracellular matrix interactions in primary huma…
2008
The hepatitis B virus (HBV) is a major causative agent of chronic liver disease and subsequent liver cirrhosis worldwide. The reduced sensitivity of virus-infected liver cells to apoptosis may play a role in the failure to remove virus-infected cells and eventually promote viral chronicity. The purpose of our study was to investigate whether survival factors induced during compensatory liver regeneration may protect hepatocytes against apoptosis. We evaluated the serum levels of hepatocyte growth factor (HGF) and epidermal growth factor (EGF) in HBV-infected patients and found significant increases in HGF and EGF in patients with active virus infection. In primary human hepatocytes we show …
Mixed cryoglobulinemia type II in chronic hepatitis B associated with HBe-minus HBV mutant: Cellular immune reactions and response to interferon trea…
1994
The case of a young female patient with chronic active hepatitis B, vasculitic purpura, edema, and circulating immune complexes due to mixed Cryoglobulinemia is described. Serum transami-nases were elevated. Serological assays showed hepatitis B surface antigen (HBsAg), antibody to hepatitis B e antigen (anti-HBe), and antibody to hepatitis B core antigen (anti-HBc) antibodies but no antibody to hepatitis C virus (anti-HCV) or antibody to hepatitis delta virus (anti-HDV) antibodies. Using hepatitis B virus-polymerase chain reaction (HBV-PCR) and direct sequencing a precore/core (preC/C) mutant unable to synthesize HBeAg was detected in serum. HBV antigens were demonstrated in the circulatin…