摘要:

AbstractAging effect on immunoregulatory processes in Peyer's patches (PP) from BALB/c mice of 3–4 months and 24–28 months was studiedin vitro. The magnitude of isotype‐specific Ig production by aged or young PP B cells in co‐culture with young or old fresh PP T cells strongly suggested that the suppressor activity of PP T cells was impaired in aged mice. Further studies onin vitroinduction of concanavalin A‐activated T helper cells, T suppressor‐inducer cells and T suppressor cells from aged PP indicated that the generation of T suppressor cells was largely impaired, in contrast to a minor defect(s) in that of T helper cells. The findings obtained here at least suggest that in aged PP, a T suppressor‐inducer cell subset appears to be more selectively impaired in the aging process than the other lymphocyte subpopulations, which possess minor intrinsic functional defects. Thus, these abnormal T and B cell responses in PP could be responsible for the senescence‐associated gut mucosal immunolo

ISSN:0014-2980    

DOI:10.1002/eji.1830170902

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe small peripheral blood CD3+T cell population lacking both CD4 and CD8 surface antigens has been analyzed in the present study. Enriched CD3+4−8−populations were obtained by depletion with anti‐CD4 or anti‐CD8 monoclonal antibodies (mAb) and complement. The resulting populations contained>99% CD2+cells, whereas CD3+represented approximately 50%. Virtually all of the cells were CD4−8−and did not react with the WT31 mAb, specific for a framework determinant of the α/β T cell receptor (TCR). In order to analyze the molecular nature of CD3‐associated molecules in CD3+WT31−populations, cells were stimulated with 0.5% phytohemagglutinin (PHA) for 24 h and expanded for an additional 7–14 days in interleukin 2 (IL2). The resulting cells were>95% CD3+and expressed neither CD4/CD8 nor WT31 antigen.Cell surface iodination followed by cross‐linking and immunoprecipitation with anti‐CD3 mAb showed that CD3‐associated molecules consisted of a major 45‐kDa band and a minor band of 43 kDa. Thus, whereas CD3‐associated molecules isolated from polyclonal CD3+WT31+populations (expanded in IL 2 under the same culture conditions) appeared as diffuse bands, CD3‐associated molecules isolated from CD3+WT31−populations displayed a homogeneous molecular mass. Northern blot analysis revealed the presence of mRNA for the TCR γ chain whereas the mRNA for the α chain was mostly represented by a truncated (1.2 kb) form. Also small amounts of a nonproductive mRNA for the β chain were detected. Freshly isolated CD3+WT31−‐enriched populations proliferated in response to PHA and concanavalin A, moreover, IL 2 was detected in the culture supernatants after cell stimulation. By applying culture conditions which allow virtually all T cells to undergo clonal expansion, approximately 1/3 CD3+WT31−were clonogenic. In addition, the large majority of proliferating microcultures lysed the K562 cell line and about half the natural killer (NK)‐resistant fresh melanoma target cells. A large number of clones derived from CD3+WT31−enriched populations by limiting dilution has been further analyzed. More than 95% of the clones were CD3+4−8−WT31−; 12/15 clones analyzed in more detail displayed NK activity and 6/15 lysed melanoma cells; in addition, all lysed P815 target cells in the presence of PHA, thus indicating that all the

ISSN:0014-2980    

DOI:10.1002/eji.1830170903

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractPure populations ofin vitropropagated bone marrow‐derived macrophages are constitutively Ia negative. Co‐culturing of these cells with recombinant interferon‐gamma (rIFN‐γ) resulted in the appearance of high amounts of Ia antigens at the cell surface of essentially all cells. The continuous presence of the stimulus was a prerequisite for sustained Ia expression because removal of the stimulus resulted in rapid decline of surface Ia.Two‐dimensional (2D) gel analysis (1D isoelectric focusing, 2D sodium dodecyl sul‐fate‐polyacrylamide gel electrophoresis) of class II molecules synthesized by rIFN‐γ‐stimulated bone marrow macrophages (BMMΦ) revealed that, in contrast to class II complexes hitherto described, BMMΦ‐derived I‐A and I‐E subregion‐encoded subunits are synthesized without invariant chains. The invariant chain‐deficient α,β heterodimers are expressed at the cell surface in high proportions demonstrating that their correct assembly and transport to the cell surface is accomplished in the absence of invariant chains. The lack of invariant chains appears not to be due to a failure of rIFN‐γ to induce transcription of the γ‐chain gene because rIFN‐γ‐induced, in contrast to uninduced, BMMΦ accumulate high levels of invariant chain‐specific transcripts as evidenced by Northern blot analysis. These findings suggest that translation of γ‐chain‐specific mRNA is blocked in BMMΦ for as yet unknown reasons. Alternatively, newly synthesized γ chains might have escaped their regular intracellular maturation pathway as a result of unidentified modifications media

ISSN:0014-2980    

DOI:10.1002/eji.1830170904

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe histamine‐producing cell‐stimulating factor (HCSF) was first described as a lymphokine which is produced during secondary mixed leukocyte culture and which induces increased histamine synthesis by murine hematopoietic cells. It has been shown that it is different from interleukin 3 (IL3), despite the fact that pure IL3 expresses HCSF activity. Our results provide evidence that this factor (constitutively produced by the P388 D1 cell line) is identical with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF)i.e.:(a) physicochemical properties of HCSF and GM‐CSF, such as molecular weight, isoelectric charge, hydrophobicity and behavior during affinity chromatography, are indistinguishable and both activities coelute during all biochemical purification procedures; (b) increased bone marrow cell histamine synthesis induced by P388 D1‐derived HCSF is inhibited by anti‐GM‐CSF antiserum; (c) the GM‐CSF cDNA probe hybridizes with a poly(A)+RNA from P388 D1 cells while no hybridizing signal was obtained with poly(A)+RNA from WEHI‐3 and from P815 cells. On the other hand, the IL3 cDNA probe hybridizes with a 1.0‐kb poly‐(A)+RNA from WEHI‐3 but not with those from P388 D1 and P815. Moreover, well known sources of GM‐CSF, such as lung conditioned medium and semi‐purified GM‐CSF from phytohemagglutinin‐induced supernatant of the murine T lymphoma LBRM‐33‐5 A4 (preparation devoid of IL 3), as well as recombinant murine GM‐CSF, induce increased histamine synthesis by hematopoietic cells. All these results demonstrate that, in our culture conditions, the P388 D1 cell line spontaneously produces GM‐CSF which is responsible for the P388 D1‐induced HCS activity. Consequently, the latter is a property shared by the two distinct hematopoietic growth factors acting on the less committed cells,i.e.IL 3 and GM‐CSF, whereas M‐CSF or G‐CSF are unable to induce histamine production. Interestingly, IL 4 which is known to support established mast cell line proliferation cannot induce HCS activity. In addition, none of the other cytokines tested, such as IL1, IL2, interferons or tumor necrosis factor can express HCS activity. This expressio

ISSN:0014-2980    

DOI:10.1002/eji.1830170905

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe cloned human γ1 heavy chain gene (HIG1) was scarcely expressed in the stable transformants of a mouse fibroblast line, L cell or a T cell line, EL4, and no γ1 heavy chain was produced in these cells. Upon treatment with cycloheximide or other kinds of protein synthesis inhibitors, the transcription of HIG1 gene was induced in L cell transformants as well as in T cell transformants. Transcription rate of bacterialgptgene, which was derived from the plasmid vector used for transfection of HIG1 gene and located just upstream of HIG1 in the transformants, was also greatly enhanced after cycloheximide treatment. But the expression of several endogenous genes in the L cells tested was not affected by the cycloheximide treatment. Nuclear transcription assay indicated that the appearance of HIG1 gene transcripts after treatment with cycloheximide was mainly due to the induction of the transcription. Deletion of an enhancer element from HIG1 gene lowered the inducing activity of cycloheximide in the L cell transformants, but a low level of HIG1 gene expression was still observed. These results suggested that trans‐acting factors similar to those present in B lymphoid cells are also functioning in non‐B lymphoid cells but their activity is inhibited by short‐lived repressor protein(s). Such repressor protein(s) appear to act on regulatory element(s) of the immunoglobulin heavy chain gene including enhancer region as well as 5′ flanki

ISSN:0014-2980    

DOI:10.1002/eji.1830170906

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe HLA class I epitope W6/32 is conformationally dependent on both heavy chain and β2‐microglobulin (β2M). Previously, the W6/32 epitope has been detected in humans and other primates as well as from bovine sources. Two controversial reports suggest the W6/32 epitope is constitutively expressed by either normal or transformed murine cells expressing the Dballele. Here we show that the appearance of the W6/32 epitope in murine cells results from the association of either the Dbor Kdgene products with either bovine or human β2M. We use congenic mouse strains and hybrid H‐2 class I genes between Dband Kbto map the W6/32 epitope to particular amino acid residues in the α2domain. Subsequently, we show that β2M exchange is not confined to murine or human cellsin vitrobut can be detected after β2M injection into a mouse. The data presented suggests that β2M exchange takes place at the cell surface under physiological conditions and indicates that MHC class I heavy chains are in an equilibrium between the bound and unbound f

ISSN:0014-2980    

DOI:10.1002/eji.1830170907

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractImmature thymocytes that lack both Lyt‐2 (CD8) and L3T4 (CD4) expression can respond rapidly to stimulation with phorbol ester and calcium ionophore by expressing some gene products characteristic of mature, activated T cells. Here we studied the effect of such short‐term stimulation on the number of copies per cell of RNA for components of the T cell receptor complex. Although, upon stimulation, mRNAs for T cell receptor β chain accumulated to higher levels, the cells did not rapidly increase their expression of α‐chain transcripts from rearranged or germ‐line genes. Transcripts from the Cγ1 (Cγ13.4) and Cγ2 (Cγ10.5) genes were differentially regulated. The rarer Cγ1 transcripts were strongly induced, while the initially abundant Cγ2 transcripts showed a modest decrease in transcripts per cell within 24 h. Thus, the ratio of these two transcripts could be shifted dramatically prior to any significant change in the cellular composition of the population. These results suggest regulatory processes that may contribute to the observed expression of γ productsin vitroor in no

ISSN:0014-2980    

DOI:10.1002/eji.1830170908

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractIn this study microglial cells isolated from brain cell cultures of newborn mice were characterized and investigated for morphology, their responses to growth factors and their functional properties. The microglial cells were phagocytic, contained nonspecific esterase activity and expressed Fc (IgG1/2b) and type‐3 complement receptors. Scanning electron microscopy revealed that in analogy to brain tissue two types of microglial cells are present in the cultures: the ameboid and the ramified type which both display similar appearance by transmission electron microscopy. Interleukin 3 and the granulocyte‐macrophage colony‐stimulating factor were potent growth factors for the cultured microglial cells. The cells were negative for class II antigens (Ia) of the major histocompatibility antigen complex. However, upon treatment with interferon‐γ (IFN‐γ) microglial cells became Ia+and functioned as antigen‐presenting cells when tested on ovalbumin‐specific Ia‐restricted helper T cells. Furthermore, microglial cells exposed to IFN‐γ and endotoxin developed tumor cell cytotoxicity and produced tumor necrosis factor α. Taken together, microglial cells share the characteristics of cells of t

ISSN:0014-2980    

DOI:10.1002/eji.1830170909

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractA monoclonal antibody, HML‐1, was produced by fusion of NSI myeloma cells with spleen cells of a mouse immunized with isolated human intestinal intraepithelial lymphocytes (IEL). Immunofluorescence studies of isolated cells, as well as immunoperoxidase staining of tissue sections, indicated that HML‐1 labeled all the various subsets of human intestinal IEL, approximately 40% of lamina propria T cells, 30% mesenteric lymphoblasts and some lymphocytes in other mucosae, particularly IEL. Conversely, it revealed only rare cells in all other lymphoid compartments. Analysis by polyacrylamide gel gradient electrophoresis showed that HML‐1 precipitated two major noncovalently bound components of approximate mol. masses of 105 and 150 kDa from human IEL. HML‐1 thus defines a novel human membrane antigen present on a subpopulation of lymphocytes preferentially associated with epithelia, and particularly with the intestinal epithelium. The characteristics of this human antigen are very similar to those of an antigen we had previously described in the rat. The possible functional role of this novel class of lymphocyte membrane antigens as well as the nature of the mechanism that triggers their expression remain to be elu

ISSN:0014-2980    

DOI:10.1002/eji.1830170910

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY

摘要:

AbstractThe requirements for antigen processing and presentation by macrophages using various forms of antigens derived fromListeria monocytogeneshave been studied. Antigen presentation was monitored by T cell‐macrophage binding and interleukin production using T cells fromListeria monocytogenes‐infected mice and specific T cell hybridomas. Antigen processing requirements were defined by three criteria: (a) inhibition by lysosomotropic agents, NH4Cl and chloroquine; (b) kinetic relationships between antigen uptake and antigen presentation; and (c) antigen presentation by macrophages pre‐fixed with glutaraldehyde. In comparing heat‐killedListeria monocytogenes(HKLM) with soluble listerial proteins (SLP), the presentation of SLP was less sensitive to lysosomotropic agents, showed faster antigen processing kinetics than with HKLM and could occur using pre‐fixed macrophages. Transitions between particulate and soluble forms had dramatic influences on processing requirements. Antigens associated with HKLM could be converted to soluble forms which did not require processing by preculture with macrophages and also by physical (e.g.sonication) and chemical (sodium dodecyl sulfate) treatments in the presence of protease inhibitors. Conversely, antigen processing was required when SLP were converted to a particulate form by covalent binding to latex beads. Analysis of SLP by molecular sieve chromatography and preparative SDS‐polyacrylamide gel electrophoresis revealed that high molecular weight proteins (>60 kDa) could be presented by prefixed macrophages without prior processing. We conclude that the transition from a particulate to soluble antigenic form can be a significant antigen proce

ISSN:0014-2980    

DOI:10.1002/eji.1830170911

出版商:WILEY‐VCH Verlag GmbH    

年代:1987

数据来源: WILEY