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Th1-type Immune Responses (th1-type + immune_response)
Selected AbstractsEnhanced ability of regulatory T cells in chronic hepatitis C patients with persistently normal alanine aminotransferase levels than those with active hepatitisJOURNAL OF VIRAL HEPATITIS, Issue 12 2009I. Itose Summary., In hepatitis C virus (HCV) infection, the Th1-type immune response is involved in liver injury. A predominance of immunosuppressive regulatory T cells (Treg) is hypothesized in patients with persistently normal alanine aminotransferase (PNALT). Our aim was to clarify the role of Treg in the pathogenesis of PNALT. Fifteen chronically HCV-infected patients with PNALT, 21 with elevated ALT (CH) and 19 healthy subjects (HS) were enrolled. We determined naturally-occurring Treg (N-Treg) as CD4+CD25high+FOXP3+ T cells. The expression of FOXP3 and CTLA4 in CD4+CD25high+ cells was quantified by real-time reverse transcriptase-polymerase chain reaction. Bulk or CD25-depleted CD4+ T cells cultured with HCV-NS5 loaded dendritic cells were assayed for their proliferation and cytokine release. We examined CD127,CD25,FOXP3+ cells as distinct subsets other than CD25+ N-Treg. The frequencies of N-Treg in patients were significantly higher than those in HS. The FOXP3 and CTLA4 transcripts were higher in PNALT than those in CH. The depletion of CD25+ cells enhanced HCV-specific T cell responses, showing that co-existing CD25+ cells are suppressive. Such inhibitory capacity was more potent in PNALT. The frequency of CD4+CD127,CD25,FOXP3+ cells was higher in CH than those in PNALT. Treg are more abundant in HCV-infected patients, and their suppressor ability is more potent in patients with PNALT than in those with active hepatitis. [source] Vaccination against hepatitis B in liver transplant recipients: Pilot analysis of cellular immune response shows evidence of HBsAg-specific regulatory T cellsLIVER TRANSPLANTATION, Issue 3 2007Tanja Bauer After liver transplantation for hepatitis-B-related diseases, patients currently receive lifelong treatment with hepatitis B immunoglobulin to prevent endogenous reinfection with hepatitis B virus (HBV). Active immunization with hepatitis B vaccine would be a preferable alternative; however, most attempts to immunize these patients with standard vaccine have failed. A recent study with a new adjuvanted hepatitis B vaccine was exceptionally successful, leading to a high-titered long-lasting antibody response in 80% of all vaccinees. To identify the immunological mechanisms behind these unexpected results, the successfully vaccinated participants were tested for hepatitis B surface antigen (HBsAg)-specific T and B cells, and their cellular responses to revaccination with conventional vaccine were studied. HBsAg-specific CD4+ T lymphocytes could be detected in 13 of 16 patients after immunization with the new vaccine. Unexpectedly, these T cells produced almost exclusively interleukin (IL)-10 and had a CD4+/CD25+ phenotype. They were functionally active, suppressing cytokine secretion in HBsAg-specific (Th1) cells, thus representing antigen-specific regulatory T cells (TReg). Following a booster dose with conventional vaccine 22-31 months after completion of the initial vaccination series, the T-cell pattern in the revaccinated individuals changed substantially: 7 days after revaccination 9 of 11 individuals showed a switch to a Th1-type immune response with HBsAg-specific T cells secreting IL-2, interferon gamma and tumor necrosis factor alpha as observed in healthy controls. Four weeks after the booster, 4 patients still showed a Th1-type cytokine pattern, whereas in 5 patients only IL-10-secreting cells were detectable. After 1 year, in 3 of 4 revaccinated individuals only IL-10-secreting cells could be found, whereas the specific T cells of the fourth patient still showed a Th1-type of response. HBsAg-specific TReg cells could be demonstrated in HBV-positive liver transplant recipients successfully immunized with a new adjuvanted vaccine. Revaccination led to immediate disappearance of the these cells and the appearance of HBsAg-specific T cells with a Th1-type cytokine profile, which in most cases were replaced by the IL-10-secreting regulatory cells during the following months. The specific induction of TReg cells could contribute to the poor response of liver transplant recipients to conventional vaccine. In conclusion,, for successful vaccination of these patients, a vaccine with a strong inhibitory effect on TReg cells would be desirable. Liver Transpl 13:434,442, 2007. © 2007 AASLD. [source] Stimulation via Toll-like receptor 9 reduces Cryptococcus neoformans -induced pulmonary inflammation in an IL-12-dependent mannerEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2005Lorna Edwards Abstract Cytosine-phosphate-guanosine-containing oligodeoxynucleotides (CpG ODN) are important vaccine adjuvants that promote Th1-type immune responses. Cryptococcus neoformans is a serious human pathogen that replicates in the lung but may disseminate systemically leading to meningitis, particularly in immunocompromised individuals. Immunization of susceptible C57BL/6 mice with CpG ODN deviates the immune response from a Th2- toward a Th1-type response following infection with C. neoformans. CpG also induces IL-12, TNF, MCP-1 and macrophage nitric oxide production. CD4+ and CD8+ T,cells producing IFN-, increase in frequency, while those producing IL-5 decrease. More importantly, pulmonary eosinophilia is significantly reduced, an effect that depends on IL-12 and CD8+ T,cells but not NK cells. CpG treatment also reduces the burden of C. neoformans in the lung, an effect that is IL-12-, NK cell- and T,cell-independent and probably reflects a direct effect of CpG on pathogen opsonization or an enhancement of macrophage antimicrobial activity. An equivalent beneficial effect is also observed when CpG ODN treatment is delivered during established cryptococcal disease. This is the first study documenting that promotion of lung TLR9 signaling using synthetic agonists enhances host defense. Activation of innate immunity has clear therapeutic potential and may even be beneficial in patients with acquired immune deficiency. [source] Generation of mature dendritic cells fully capable of T helper type 1 polarization using OK-432 combined with prostaglandin E2CANCER SCIENCE, Issue 12 2003Marimo Sato Dendritic cell (DC) administration appears to be a very promising approach for the immunotherapy of cancer. The results of clinical studies have suggested that the nature and the magnitude of antitumor immune responses are critically affected by DC functions, including production of T helper type 1 (Th1)-inducing cytokines, activation of T cell subsets and natural killer (NK) cells, and migration from peripheral tissues to the T cell area of the draining lymph nodes. Administration of immature DCs could fail to fully stimulate antigen-specific immune responses and might induce tolerance under some conditions. In this study, we developed a method to obtain fully mature DCs, and we compared in detail the DCs thus obtained with those obtained using a maturation stimulus termed monocyte-derived medium (MCM)-mimic, which is a mixture of recombinant cytokines and prostaglandin E2 (PGE2) mimicking the components of monocyte-conditioned medium. Using DCs derived from monocytes of advanced cancer patients in this study, we found that DCs stimulated with OK-432 alone showed phenotypes similar to those of mature DCs induced using MCM-mimic, though with better secretion of IL-6 and IL-12. However, these DCs were found to have poor migratory capacity associated with the marginal expression of CCR7. When OK-432 was combined with PGE2, the CCR7 expression and migratory capacity of DCs were significantly improved without impairing other immuno-stimulatory functions. These results suggest that stimulation with the combination of OK-432 and PGE2 could be applicable as an alternative to MCM-mimic in clinical trials which require fully matured DCs to induce Th1-type immune responses against tumor cells even in patients with advanced cancer. [source] Toll-like receptor ligands as adjuvants in allergen-specific immunotherapyCLINICAL & EXPERIMENTAL ALLERGY, Issue 12 2005P. Johansen Summary Background Allergen-specific immunotherapy (SIT) leads to long-term amelioration of T-helper type 2 (Th2)-mediated allergic symptoms and is therefore recommended as a first line therapy for allergies. The major disadvantage of SIT is its low efficiency, requiring treatment over years. Objective In this study, we evaluated the potential of Toll-like receptor (TLR) ligands to facilitate Th1-type immune responses. Methods The immunogenicity and therapeutic potential of the major bee venom allergen phospholipase A2 (PLA2) combined with various TLR ligands were tested in mice and compared with immune responses induced by conventional aluminium-based preparations. Results Regarding total IgG against PLA2, TLR2/4-binding lipopolysaccharide and TLR3-binding polyriboinosinic polyribocytidylic (PolyI:C) were the superior adjuvants for prophylactic vaccination. However, TLR9-binding phosphorothioate-modified cytosine,guanosine-rich oligonucleotide (CpG), TLR-3-binding PolyI:C, and TLR2/6-binding peptidoglycan skewed the immune responses more towards IgG2a isotype and Th1 cytokines. Furthermore, in a therapeutic approach, CpG, PolyI:C and TLR7/8-binding 3M003 had immune modulating properties as they suppressed established IgE titres. Conclusion The potential of TLR ligands to adjuvate the immunogenicity of bee venom PLA2 and to skew the Th1,Th2 balance proved very heterogeneous. With respect to SIT, CpG, PolyI:C, and 3M003 were very promising. Hence, TLR ligands should be considered as adjuvants or immune modulators in SIT in human as to improve its efficiency regarding the Th1,Th2 balance of the immune response with a likely effect on therapy duration. [source] | ||||||||||