摘要:

AbstractInterleukin (IL) 6 was compared to other macrophage‐derived products for its capacity to support the proliferation of accessory cell‐depleted T cells. Monoclonal anti‐IL 6 antibodies were found to inhibit completely the “accessory activity” of macrophage supernatants, thus demonstrating the central role played by IL 6 in T cell activation. IL 6 was apparently more critical for initiating than in maintaining T cell proliferation because anti‐IL 6 antibodies lost all inhibitory activity when added late to the culture. Moreover, IL 6 was not the only accessory factor required for optimal T cell proliferation. Using low‐density cultures to minimize the number of contaminating accessory cells, we found that significant proliferation of CD4 cells was obtained only in the presence of both IL 6 and IL 1. In contrast, with CD8 cells substantial proliferation was obtained with IL 6 alone. This response could, however, be enhanced by IL 1. Tumor necrosis factor (TNF) and granulocyte/macrophage colony‐stimulating factor showed no activity in these assays. The concentrations of IL 1 and of IL 6 required to support optimal proliferation were 10 pg/ml and 1 ng/ml, respectively.Analysis of the mechanisms underlying T cell activation by IL 1 and IL 6 indicated that both cytokines were required for optimal production of IL 2 but that IL 6 alone was sufficient to confer IL 2 responsiveness. For CD8 cells, this effect was observed with doses of IL 6 about 100 times lower than those required for the induction of IL 2 secretion (0.001vs.0.1 ng/ml). TNF, which was not capable of inducing IL 2 secretion, was also found to induce IL2 responsiveness but only at a concentration ≈ 1000 times higher than that of IL 6. In accordance with these observations, IL 6 and to a lesser extent TNF were found to enhance IL 2R expression by CD8 cells. Interestingly, this enhancing effect was totally dependent on the

ISSN:0014-2980    

DOI:10.1002/eji.1830200102

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractByin vitrotransformation with Epstein‐Barr virus (EBV), we have previously established EBV lymphoblastoid cell lines (LCL) from a patient with leukemic centrocytic B cell lymphoma. EBV‐transformed LCL and EBV genome‐negative leukemic B cells showed identical chromosome aberrations and IgH gene rearrangements. In the present study we have analyzed the effect of exogenous cytokines [interleukin (IL) 1, 2, 3, 4, 6, tumor necrosis factor, lymphotoxin, transforming growth factor β, (TGF‐β)] and anti‐IgM antibodies on thein vitroproliferation of EBV−leukemic B cells and EBV‐converted LCL. In contrast to conventional chronic lymphocytic leukemia, B cells of the patient DUL spontaneously proliferated for up to two weeks in the absence of exogenous lymphokines. The spontaneous proliferative capacity of clonal DUL B cells was not modulated by IL 1, IL 3, IL 6, TNF or LT.In vitrogrowth of DUL B cells was increased, however, by exogenous recombinant (r)IL 2, and was abrogated by TGF‐β, rIL 4 and anti‐IgM. rIL 4 not only inhibited spontaneous B cell proliferation but also neutralized the enhancing effect of rIL 2. In contrast, growth of the EBV‐transformed DUL LCL was not affected by any of these factors. These data demonstrate thatin vitroinfection and transformation of a clonal B cell population by EBV induces a switch in responsiveness to rIL 4, TGF‐β and anti‐IgM. In addition, this report is the first to demonstrate an inhibitory effect of rIL 4 on a spontaneously proliferating

ISSN:0014-2980    

DOI:10.1002/eji.1830200103

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThis study reports on the earliest stages of mononuclear phagocyte differentiation. A crucial question in this developmental process is whether mature macrophage (Mϕ) heterogeneity is already appointed at the precursor cell level. For this purpose, we produced clonal populations of mononuclear phagocytes from bone marrow culture by somatic cell hybridization with two hypoxanthine, aminopterin, thymidine‐sensitive myeloid cell lines. A panel of 22 stable hybrids was obtained from these fusions. Differentiation stage analysis of the hybrids indicated that all cell lines had immature mononuclear phagocyte characteristics. The hybrids exhibited typical myeloid morphology and mainly nonadherent growth. Mature Mϕ features, such as expression of the cell surface antigens Mac‐1, Mac‐2 and F4/80, phagocytosis of latex beads, and expression of nonspecific esterase and acid phosphatase activity, were virtually absent. The immature Mϕ markers Thy‐1, MIV 25 and MIV 52, on the other hand, were readily expressed, although heterogeneity was observed among different hybrid cell lines.We then analyzed the differentiation potential of seven hybrids by culture of the cells in the presence of post‐lipopolysaccharide serum supplemented with interferon‐γ and found that the expression of mature Mϕ characteristics was induced. However, the various hybrids showed divergent patterns of mature Mϕ marker induction. ROC2 cells, for instance, showed extensive morphological and phenotypical differentiation without concomitant induction of phagocytosis. In contrast, W1C4 cells showed significant induction of phagocytosis without simultaneous increase of phosphatase and esterase activity. R1C1 cells were unique in the strong induction of Ia antigen expression.Together, our data indicate that (a) early Mϕ differentiation stages can be rescued by somatic cell hybridization, and that (b) the obtained cell lines are able to mature according to divergent differ

ISSN:0014-2980    

DOI:10.1002/eji.1830200104

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe aim of the present study was the phenotypical analysis of early stages in macrophage (Mϕ) differentiation. For this purpose, we produced a panel of syngeneic rat hybridomas, which secreted antibodies (mAb) against Mϕ precursor antigens. As immunogens we used immortalized Mϕ precursors (P. J. M. Leenen et al.,Eur. J. Immunol.1990.20:15). We screened the obtained mAb in the followingin vitromodels of Mϕ differentiation: (a) a panel of Mϕ cell lines ordered in a linear differentiated sequence; (b) immature and mature mononuclear phagocytes obtained from bone marrow (BM) culture; (c) a panel of Mϕ precursor hybrids, and (d) differentiated and control Mϕ precursor hybrid cells.Four mAb, ER‐MP12, ER‐MP20, ER‐MP54 and ER‐MP58, were selected. These mAb recognize antigens which disappear in the course of Mϕ differentiation. Next, we investigated whether these mAb also recognized Mϕ precursors in normal BM. For this purpose, ER‐MP‐positive and ‐negative BM fractions were isolated using a fluorescence‐activated cell sorter. Fractions were cultured in Mϕ‐colony‐stimulating factor‐containing conditioned medium, and the resulting mature Mϕ progeny was quantified using the MTT assay. The present experiments indicate that ER‐MP12 and ER‐MP20 detect a subpopulation of BM Mϕ precursors, whereas ER‐MP58 stains virtually all Mϕ precursors.Biochemical analysis of radioiodinated antigens revealed that these mAb recognize different molecules. ER‐MP12 and ER‐MP20 bound to single‐chain (glyco)proteins of 140 kDa and 14 kDa, respectively. ER‐MP54 precipitated multiple polypeptides, of which the major chains have an apparent molecular mass of 90, 80‐85 and 70‐75 kDa. Based on the molecular mass of the recognized antigens and the mAb specificities we conclude that ER‐MP12, ER‐MP54 and ER‐MP58 recognize hitherto unknown antigens of murine Mϕ precursor cells. The an

ISSN:0014-2980    

DOI:10.1002/eji.1830200105

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractExpression of a critical level of major histocompatibility complex (MHC) class I antigens on epithelial cells is a prerequisite for the action of specific cytolytic immune response cells. Glucocorticoid hormones have strong immunosuppressive effects. Therefore, we investigated the influence of the synthetic glucocorticoid dexamethasone on the expression level of MHC class I antigens on human epithelial cell lines. Long‐term treatment with dexamethasone leads to reduced MHC class I surface antigen expression and to decreased total membrane‐bound MHC class I protein. The steady‐state mRNA level is significantly decreased and the transcription rate of MHC class I genes is re

ISSN:0014-2980    

DOI:10.1002/eji.1830200106

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractMost CD4−CD8−adult murine thymocytes characterized by absence of the B2A2 (J11d) antigen express T cell receptors (TcR) α/β and utilize preferentially Vβ8.2 segments. To a much lesser extent, B2A2−CD4−CD8−thymocytes also express TcR γ/δ, as evidenced by biochemical and Northern blot analysis. We have now been able to exclude the possibility that these cells might co‐express both types of TcR: Vβ8 B2A2−CD4−CD8−thymocytes expressed no TcR δ mRNA whereas the corresponding Vβ8−subset transcribed full‐length TcR γ as well as δ mRNA. Furthermore, the TcR γ/δ expressing B2A2−thymocytes were found to use preferentially Vδ6 genes. Conversely, they did not express Vδ5 genes which are most frequently used by other TcR γ/δ‐bearing populations such as B2A2 CD4−CD8−thymocytes or CD4−CD8−peripheral lymph node cells. RNase protection experiments showed that two particular Vδ6 transcripts predominate in these γ/δ populations, the most prominent Vδ6 sequence being highly homologous if not identical to Vα7.1. Our observations extend previous information on overlapping Vαand Vδgene repertoires, particularly in the cross‐hybridizing Vα7/Vδ6 gene family. Moreover, our data suggest that B2A2−CD4−CD8−thymocytes represent a developmentally uniq

ISSN:0014-2980    

DOI:10.1002/eji.1830200107

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractA cloned epithelial cell line, TEL‐2, has been established from the stroma tissues of normal mouse thymus. Incubation of mouse thymocytes on TEL‐2 cells resulted in the selective elimination of double‐positive (CD4+CD8+cells from the culture, whereas single‐positive (CD4+CD8−or CD4−CD8) thymocytes remaining in the culture were concentrated in non‐integrated cell population. The CD3−or CD3 low‐positive thymocytes were also eliminated by the TEL‐2 cells from the culture, followed by the concentration of CD3 high‐positive cells in the culture. Only intact viable thymocytes were integrated into TEL‐2 cells. Electron microscopic examination showed that the integrated cells into TEL‐2 cytoplasm were gradually degenerated. Mature single‐positive T cells, mature B cells or double‐negative thymocytes were not integrated into TEL‐2 cells. The TEL‐2 cell may provide information on the mechanism of selective disappearance of double‐posi

ISSN:0014-2980    

DOI:10.1002/eji.1830200108

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractIn this work, we analyzed the immunoglobulin heavy (H) and light (L) chain production by two variant B hybridomas, UN2.C3 and UN2.C17.K1 co‐cultured with cells from a FcγRII, IgG‐binding factor (IgG‐BF)‐producer T hybridoma (T2D4.C1) or with cells of a FcγRII−, IgG‐BF‐nonproducer variant (D10C5). We showed that only the FcγRII hybridoma directly inhibits the IgG secretion by UN2.C3 through a soluble mediator. This inhibition affects the H and L chain synthesis as well as the H and L chain‐encoding mRNA steady state. No apparent cytotoxic effect could be detected. In contrast, the production of ϰ chain by an H chain‐negative variant (UN2.C17.K1) was unaffected. This indicates that a complete IgG molecule is required to observe the inhibitory effect induced by T2D4.C1. The pattern of effector/target cell interactions observed in our work suggests that the soluble factor involved in the suppression of IgG production is IgG‐BF, able to transiently modify the IgG gene exp

ISSN:0014-2980    

DOI:10.1002/eji.1830200109

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractThe lipopeptide N‐palmitoyl‐S‐(2,3‐bis(palmitoyloxy)‐(2RS)‐propyl)‐(R)‐cysteinyl‐alanyl‐glycine (Pam3Cys‐Ala‐Gly), a synthetic analogue of the N‐terminal part of bacterial lipoprotein, induces the secretion of interleukin (IL) 1, IL 6 and tumor necrosis factor (TNF)‐α in bone marrow‐derived macrophages that have been culturedin vitrofor up to 20 days. IL 6 and TNF‐α secretion increased from day 6 to day 20 whereas IL 1 secretion increased until day 13 and decreased on day 20. In contrast to the enhancement of cytokine production, phagocytosis of IgG‐coated sheep erythrocytes and Ia expression were found to be diminished after treatment with lipopeptide for 24 h. Morphological studies revealed lipopeptide‐induced changes of macrophage cultures. The data presented here show the potential of the lipopeptide as a strong activat

ISSN:0014-2980    

DOI:10.1002/eji.1830200110

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY

摘要:

AbstractIn order to investigate the role of T cell receptor (TcR) expression in thymocyte maturation, we have analyzed thymocytes from C.B‐17/SCID mice, which are unable to productively rearrange their antigen receptor genes and fail to express TcR. Despite this defect, SCID thymocytes are functional as they produce lymphokines and proliferate in response to a variety of stimuli. Phenotypic analysis revealed that thymocyte populations from young adult SCID mice resemble thymocyte populations from normal embryonic mice in that they are large, Thy‐1.2+, CD4−, CD8−, TcR−and enriched in CD5lo, IL2R+and Pgp1+cells. However, other TcR−populations normally present in adult mice (i.e., CD4−CD8+cells and CD4+CD8+cells) are absent from the thymus of TcR−adult SCID mice. To understand the basis of the developmental arrest of TcR−SCID thymocytes at the CD4−CD8−stage of differentiation, we analyzed thymi from the occasional “leaky” SCID mouse which possesses small numbers of TcR+thymocytes. We found that the presence of TcR+cells within a SCID thymus was invariably associated with the presence of CD4+and/or CD8+SCID thymocytes. Interestingly, however, the CD4+/CD8+SCID thymocytes were not themselves necessarily TcR+. That is, emergence of SCID thymocytes expressing CD4/CD8 was tightly linked to the presence of TcR cells within that SCID thymus, but the SCID thymocytes that expressed CD4/CD8 were not necessarily the same cells that expressed TcR. Finally, we found that the introduction into TcR−SCID mice of normal bone marrow cells that give rise to TcR+cells within the SCID thymus promoted the differentiation of SCID thymocytes into CD4−CD8+and CD4+CD8+TcR−cells.These data indicate that TcR+cells within the thymic milieu provide critical signals which promote entry of CD4−CD8−TcR−precursor T cells into the CD4/CD8 differentiation pathway. When applied to differentiation of normal thymocytes, these findings may imply a critical role for early appearing CD4−CD8−TcR (γ/δ)

ISSN:0014-2980    

DOI:10.1002/eji.1830200111

出版商:WILEY‐VCH Verlag GmbH    

年代:1990

数据来源: WILEY