摘要:

AbstractThe Rel/NF‐ϰB proteins, p50, p52, p65, c‐Rel, and RelB, constitute a family of transcription factors involved in the positive regulation of a variety of genes during the immune response. Recently, it has been shown that RelB knockout mice have no dendritic cells (DC). An overexpression of p50 has been described in follicular dendritic cells (FDC). A constitutive NF‐ϰB activity has been reported in mature macrophages. This led to the hypothesis that some of the Rel/NF‐ϰB proteins were key nuclear factors in functions of accessory cells of the immune response. Therefore, we investigatedin situthe nuclear localization of Rel/NF‐ϰB proteins in accessory cells of the immune system by immunohistochemistry and double labeling by immunofluorescence from five normal human tonsils and five lymph nodes with follicular hyperplasia. Nuclear p65 and c‐Rel proteins were found in all cell types including lymphocytes. In germinal centers GC, p50, p52, and RelB were found in the nuclei of FDC only and were not detected in the nuclei of CD68+cells. In T cell areas, p50, p52, and RelB were found in the nuclei of HLA‐DR+cells with an antigen‐presenting cell (APC) morphology. p52 and RelB were detected in the nuclei in both CDla+and CD68+cells from the T cell area, whereas p50 was found only in CD68−and CDla−cells. Cells with nuclear p50 were negative for the CD38, CD20 and CD2 markers. These results show that, physiologically, high levels of nuclear of p50, p52 and RelB are restricted to accessory cells of the immune system, which include FDC in GC, and DC and macrophages in the T cell zone, that specialized scavenger macrophages from GC do not have detectable levels of p52 and RelB, whereas macrophages from the T cell area, known to present the antigen to T cells, do have both nuclear p52 and RelB, and that in the T cell zone, p52 and RelB are located in nuclei of both CDla+, CD68+or both, cells APC, whereas p50 is restricted to CDla−and CD68−APC. The different patterns of p50, p52 and RelB protein nuclear localization may provide insight into their different roles during

ISSN:0014-2980    

DOI:10.1002/eji.1830261102

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractVarious mouse and rat strains show different susceptibilities to experimental autoimmune myasthenia gravis (EAMG) that can be induced by immunization with acetylcholine receptor (AChR) and Freund's complete adjuvant, and represents a model for the antibody‐mediated myasthenia gravis in humans. We examined AChR‐induced B and T cell responses and cytokine mRNA expression to study the mechanisms behind susceptibility to EAMG in Lewis rats and resistance in Wistar Furth (WF) rats. Both strains had similarly elevated concentrations and affinities of serum anti‐AChR antibodies, and no difference between the two strains for frequencies of cells in lymphoid organs expressing mRNA of the B cell stimulating cytokine interleukin‐4 was found. In contrast, T cell responses to AChR measured by proliferation and by enumeration of interferon‐γ‐expressing cells at both mRNA and protein level were lower in the resistant WF rats. This strain showed, instead, an up‐regulation of the anti‐inflammatory transforming growth factor‐β. Strain‐related differences in the susceptibility to actively induced EAMG are thus related to quantitative differences in distribution between pro‐inflammatory and anti

ISSN:0014-2980    

DOI:10.1002/eji.1830261103

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractTumor cells were engineered to express a specific recall antigen molecule to serve as a target for the host's existing memory response, and then used as immunogens as a novel form of cancer vaccine. As recall antigen, the efficiently expressible hybrid protein Heat1 was employed, that contains an antigenic fragment of theMycobacterium bovis65‐kDa heat shock protein (hsp65), and thus can be recognized in mice immunized with live Bacillus Calmette‐Guérin (BCG) or its derivatives. Mouse M‐3 melanoma cells were transfected to express Heat1, irradiated, and used as anti‐melanoma vaccines. Vaccination elicited anti‐tumor immunity in mice,i.e.a subsequent challenge with the parental wild‐type M‐3 melanoma cells was rejected. Successful vaccination was dependent on the correct recognition of the recall antigen, since vaccination failed to prevent outgrowth of the challenge in mice possessing no memory response against the recall antigen. The results indicate that expression of a recall antigen can turn tumor cells into powerful vaccines. By using the Heat1 protein or other appropriate antigens, this general concept may be applied for

ISSN:0014-2980    

DOI:10.1002/eji.1830261104

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractA conditionally immortalized dendritic cell line was established from bone marrow of mice transgenic for a thermolabile mutant of the SV40 large T antigen under the control of the class I Kbpromoter. At the permissive temperature of 33°–37°C, the line divides in the absence of granulocyte/macrophage colony stimulating factor. It shares a number of cell surface markers with bone marrow macrophages, but unlike macrophages, is constitutively major histocompatibility complex (MHC) class II+, negative for nonspecific esterase and unable to phagocytose sheep red blood cells. The cells show characteristic dendrites, an abundance of acidic vesicles and are highly active in endocytosis. If maintained at 33°C, the dendritic cell line processes and presents exogenous protein to MHC class II‐restricted T cell hybrids and acts as potent mixed lymphocyte reaction stimulator, but fails to activate naive, resting T cells. Transfer to 39°C arrests growth and results in up‐regulation of surface markers such as B7.1, CD40 and intercellular adhesion molecule‐1. Further up‐regulation of cell surface markers and acquisition of functional maturity occur following contact with T cells and their cognate antigen or in culture with a cytokine mixture derived from acti

ISSN:0014-2980    

DOI:10.1002/eji.1830261105

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractCD43 is a major surface sialoprotein on hemopoietic cells, whose extracellular domain is heavily O‐glycosylated. The functional role of CD43 in the hemopoietic system is not fully understood; however, it has been suggested that CD43 may have a role in cell‐cell repulsion and in modifying T cell proliferation and activation. CD43 is expressed in immature B cells in the bone marrow, but not by peripheral B cells, except for B‐1 B cells and plasma cells. To analyze the biological effect of CD43 in B‐lineage cells, we transfected mouse CD43 cDNA into a CD43−B cell lymphoma, WEHI 231, and the growth and survival in culture were compared to those of a parental cell line, human CD8 transfectants, and CD43−revertants established from CD43+clones. We observed that CD43 expression supported cell growth in culture upon serum reduction, whereas growth of CD43−cell lines was barely detected under this condition. CD43−cell lines accumulated in G1phase of the cell cycle, and the numbers of viable cells were greatly reduced during culture upon serum depletion, whereas expression of CD43 reduced the susceptibility to G1arrest and temporarily retarded the apoptotic process, which, in turn, resulted in an increase and maintenance of the number of viable cells in culture. The results suggest that CD43 may have some role in the survival and expansion of B‐lineage cells. The biological effect of CD43 was initiated without stimulation by cross‐linking and was significantly impaired by replacement of the extracellular domain by the human CD8 extracellular domain. The basis of these regulatory pro

ISSN:0014-2980    

DOI:10.1002/eji.1830261106

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractThe cytolytic activity of human and mouse natural killer (NK) cells is negatively regulated by self major histocompatibility complex (MHC) class I molecules on potential target cells. In the rat, protection by RT1 class I gene products has so far not been formally shown although the complex effects of foreign and selfRT1genes on polyclonal NK cell activity suggest that MHC recognition can have both stimulatory and inhibitory effects. Here we report that the expression of self‐MHC class I molecules on target cells strongly inhibits lysis by a long term NK cell line derived from LEW (RT1l) rats and by LEW NK cells activated by short‐term culture in the presence of interleukin‐2. This was demonstrated with mouse‐rat hybridoma target cells expressing different rat MHC alleles and with mouse tumor target cells transfected with classical (RT1.Al) and nonclassical (RT1.Cl) rat MHC class I genes. With hybridoma target cells, the strongest reduction in lysis as compared to the parental mouse myeloma line was observed when “self” (LEW) MHC was expressed, while hybridomas expressing other MHC alleles showed less and variable reduction. Transfection ofRT1.Alprotected both L‐929 fibroblasts and P815 mastocytoma cells from lysis by the NK cell line, whileRT1.Clonly protected P815 cells, indicating that additional target cell properties regulate rat NK

ISSN:0014-2980    

DOI:10.1002/eji.1830261107

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractCholera toxin (CT), the enterotoxin ofVibrio cholerae, is a potent mucosal immunogen as well as a strong mucosal adjuvant to related and unrelated antigens. The mucosal immune response to CT is T cell dependent and MHC class II restricted. The epitopes on CT recognized by T cells have not been identified. The purpose of this study was to determine the fine specificity of T cell recognition of both the CT A subunit (CT‐A) and the CT B subunit (CT‐B) by using a range of synthetic peptides. After immunization with CT‐B or CT‐A in CFA subcutaneously, the peripheral lymph node T cells were stimulated with different synthetic peptidesin vitroThe peptide specificity of T cell recognition was identified by assaying T cell proliferation and interleukin‐3 production. T cells from C57BL/6 (H‐2b) high responder mice recognized one immunodominant epitope (peptide 89–100) and one weak epitope (peptide 31–50) on CT‐B and two epitopes (peptide 21–39 and 180–194) on CT‐A. The immunization of C57BL/6 mice with synthetic immunodominant CT‐B peptide 89–100 induced T cell immunity to the pentameric CT‐B. Induction of tolerance to CTB peptide 89–100 by i.v. injection in high responder C57BL/6 mice induced unresponsiveness to mucosal immunization with CT, compatible with an immunodomina

ISSN:0014-2980    

DOI:10.1002/eji.1830261108

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractPrevious reports have indicated that both dendritic cells and macrophages have the ability to induce cytotoxic T lymphocyte (CTL) and T helper (Th) cell responsesin vivo. Dendritic cells process exogenous antigens conventionally for presentation on major histocompatibility complex (MHC) class II molecules. However, unconventional processing of exogenous antigensin vitrofor presentation on MHC class I molecules is still an open question. In this study, we report that a cloned dendritic cell line (D2SC/1) is able to present cell debris‐associated exogenous viral proteins to MHC class I‐restricted CTLin vitroThe dendritic cell line was very efficient in processing recombinant lymphocytic choriomeningitis virus nucleoprotein (LCMV NP) and presenting the class I‐restricted epitope to CTL primedin vivo. Peritoneal macrophages could also process the recombinant LCMV NP for subsequent MHC class I presentation, but were less efficient compared to the dendritic cells. Furthermore, recombinant yeast‐derived virus‐like particles carrying the HIV‐1 V3 loop (V3‐VLP), which are protenaceous and do not contain any lipid, were also found to be efficiently processed by the dendritic cell line for presentation of the class I‐restricted epitope. These results clearly indicate that viral proteins, in particulate form or associated with cell debris, are processed by dendritic cells fo

ISSN:0014-2980    

DOI:10.1002/eji.1830261109

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractCatecholamines have been shown to inhibit some aspects of macrophage activation through a β receptor‐dependent mechanism. This study was undertaken to analyze the effects of isoproterenol, a specific β‐adrenergic agonist, on the synthesis of interleukin‐10 (IL‐10), a major macrophage‐deactivating factor. Isoproterenol increased IL‐10 release from lipopolysaccharide‐(LPS)‐activated mouse peritoneal macrophages in a dose‐dependent manner. A significant effect was already observed with 1 μM isoproterenol, while a 4.5‐fold increase was achieved with 10 μM. This increase was observed only if macrophages were exposed to isoproterenol for at least 2 h before LPS challenge. It was apparent within 0.5 h and persisted through 24 h at all the LPS concentrations used. A similar increase was observed at the IL‐10 mRNA level, as judged by enzyme‐linked immunosorbent assay‐polymerase chain reaction. The macrophage response to isoproterenol that led to cyclic AMP accumulation was markedly inhibited by H‐89, a potent inhibitor of protein kinase A. These data suggest the involvement of cyclic AMP in the regulation of IL‐10 synthesis by isoproterenol. IL‐10 was in turn partly responsible for a reduction in tumor necrosis factor‐α synthesis.In vivo, the administration of oxprenolol, a β‐receptor antagonist, significantly reduced serum IL‐10 levels 90 min after LPS challenge. Thus, the present study provides the first evidence that endogenous catecholamines are of critical importance in determining the magnitude of the

ISSN:0014-2980    

DOI:10.1002/eji.1830261110

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY

摘要:

AbstractCutaneous sensitization to reactive haptens and subsequent challenge results in a T cell‐mediated response, contact hypersensitivity (CHS). Recent results from this laboratory have indicated that hapten sensitization induces two populations of reactive T cells: CD8+T cells producing interferon (IFN)‐γ which mediate the response and CD4+T cells producing interleukin (IL)‐4 and IL‐10 which negatively regulate the magnitude and duration of the response. Since CD4+T cell development to either IFN‐γ‐ (Th1) or IL‐4/IL‐10‐ (Th2)‐producing cells is dependent upon the cytokine environment during antigen priming, we hypothesized that CD4+T cell induction in a Th1‐promoting environment would not only alter the CD4+T cell cytokine‐producing phenotype but also the course of the CHS response. Administration of the Th1‐promoting cytokine IL‐12 during hapten sensitization resulted in a CHS response of greater magnitude following challenge and extended the duration of the response. In hapten‐sensitized mice depleted of CD8+T cells, treatment with IL‐12 induced effector CD4+T cells. Histological examination of challenged ear tissue from these mice indicated minimal edema and an acute mononuclear cell infiltration more typical of classical delayed‐type hypersensitivity than CHS. Hapten‐primed CD4+T cells from IL‐12 treated, sensitized mice produced IFN‐γ, but not IL‐4 in response to T cell receptor‐mediated stimulation. Use of neutralizing anti‐IFN‐γ antibody indicated that IL‐12 not only directly promoted Th1 development but also indirectly inhibited Th2 development through stimulation of IFN‐γ production at the time of hapten sensitization. Overall, these results demonstrate that diversion of CD4+T cell development to Th1 effector cells rather than to Th2 cells alters the efferent nature of CHS and remov

ISSN:0014-2980    

DOI:10.1002/eji.1830261111

出版商:WILEY‐VCH Verlag GmbH    

年代:1996

数据来源: WILEY