摘要:

AbstractThe function of a human cytokine, lymphocyte blastogenesis inhibitory factor (LBIF), was characterized. To this end, LBIF was purified from crude supernatant of U‐937 cells, a human macrophage‐like cell line, by using fast protein liquid chromatography (FPLC).We demonstrated here that (a) the LBIF preparation completely inhibited phytohemagglutinin (PHA)‐stimulated T cell proliferation; (b) however, in PHA‐stimulated T lymphocytes LBIF inhibited neither interleukin (IL)2 production nor the expression of IL2 receptor (IL2R) light chain (CD25) which play a critical role for T cell proliferation; (c) LBIF arrested PHA‐stimulated T lymphocytes at the G1phase of cell cycle and inhibited entry into S phase, thus inhibiting lymphocyte proliferation. Wright‐Giemsa's staining of the cells showed that PHA/LBIF‐stimulated cells were arrested in early G1. In agreement with this result, LBIF strongly inhibited PHA‐induced RNA synthesis. Further, LBIF inhibited the induction of the transferrin receptor which is normally expressed at the late G1phase of the cell cycle. The inhibitory activity of LBIF was reversible. Thus, this study elucidated that LBIF arrests PHA‐stimulated T lymphocytes at a point between the stages of IL 2 production or IL2R light chain expression (in early G1) and transferrin receptor expression (in late G1). Taken together, these results suggest that there might be a control system of T cell proliferation distinct from the previously reported mechanisms, such as the inhibition of IL2 production or the inhibition of IL 2R light chain (CD25) expression, and that LBIF might be an important molecule in the regulation of normal lymphoc

ISSN:0014-2980    

DOI:10.1002/eji.1830190802

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractIn the present study, we describe a new regulatory system that influences thein vivodevelopment of cytotoxic T lymphocytes (CTL) and that could be related to epitopic suppression. Epitopic suppression has been previously shown to occur when carrier‐primed mice are subsequently immunized with a “new” epitope coupled to the priming carrier. The suppression specifically inhibited the antibody response to the “new” epitope without affecting the secondary antibody response to the carrier.In this report, using a carrier/hapten‐carrier type of immunization protocol, we have demonstrated that a similar regulatory system could also affect the induction of CTL directed against allogeneic cells. Priming mice with an alloantigen 1 (carrier) inhibits the induction of alloantigen 2 (hapten)‐specific cytotoxic responses when the alloantigen 2 is presented in association with the alloantigen 1 on an F1stimulator cell (hapten‐carrier conjugate). This has been demonstrated by the specific decrease of anti‐H‐2bor anti‐H‐2dCTL responses generated in C3H/He mice (H‐2k) previously primed with, respectively, H‐2dor H‐2bspleen cells before immunization with F1(H‐2d x b) spleen cells. This suppression of the CTL responses against the second immunizing alloantigen is associated with a strong CTL response against the first priming alloantigen. The induction of the suppression is dependent on the dose of H‐2dspleen cells administered before immunization with F1spleen cells and is not related to antigen elimination since a strong suppression of the CTL response against H‐2bantigens is shown following immunization with a mixture of F1cells and H‐2b

ISSN:0014-2980    

DOI:10.1002/eji.1830190803

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe monoclonal antibody HC1/6 generated against phorbol 12‐myristate 13‐acetatetreated U‐937 cells recognizes a new cell surface antigen with a broad relative molecular mass ranging from 100 to 150 kDa. This antigen is also present on monocytes, platelets and endothelial cells and is weakly expressed by granulocytes. In contrast, it is absent from T, B and erythroblastoid cells. The antigen HC1/6 is also expressed by normal tissue macrophages in tonsil, lung and kidney, as well as in skin biopsies from pathologies such as sarcoidosis and lepromatous leprosy. The expression of the HC1/6 antigen is increased up to 5‐fold when U‐937 (promonocytic) and HL‐60 (myelomonocytic) cell lines are stimulated with phorbol 12‐myristate 13‐acetate. Conversely, the expression of the HC1/6 antigen is down‐regulated in monocytes upon treatment with interferon‐γ. These findings are discussed in relation with other myeloid

ISSN:0014-2980    

DOI:10.1002/eji.1830190804

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractIn this report, we analyze the expression of the type II receptor for the Fc region of IgG (FcγRII) in resting and lipopolysaccharide (LPS)‐activated murine B lymphocytes. FcγRII is encoded by two genes, α and β. The β gene encodes two mRNA, β1 and β2, which are generated by alternative splicing. Using an S1 nuclease protection assay, we found that resting and activated B lymphocytes express predominantly the β1 transcript. Very low levels of the β2 mRNA were detected in this assay, while no expression of the α transcript could be detected. Quantitative Northern blot analysis showed that the amount of FcγRII β mRNA was increased 9‐fold in LPS‐activated B lymphocytes. The expression of FcγRII during the various phases of B cell activation was then studied by immunofluorescence using the monoclonal antibody 2.4G2. LPS stimulation induced an increase of the FcγRII cellular pool as well as of its expression at the surface of B lymphocytes. The rise in FcγRII surface expression occurred after the induction of class II antigens (la) and before transferrin receptor induction. FcγRII expression was found to be enhanced during the G1phase of the cell cycle since (a) only large cells (i.e.those that had entered the G1phase) expressed an increased amount of FcγRII and (b) blocking the entry of activated cells into the S phase (with the ion channel blocker quinine) did not affect the FcγRII induction by LPS. Furthermore, only B cell activators that induced cells to enter into G1[LPS and F(ab')2anti‐IgM antibodies, but not interleukin 4] caused an increase in the expression of FcγRII. These results show that the increase in the membrane expression of FcγRII occurs during the early G1phase, establishing it as a marker for the entry of B lymp

ISSN:0014-2980    

DOI:10.1002/eji.1830190805

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractInvestigation of the nature of immunological self tolerance has usually relied upon experimental protocols in which the tolerant state is interrupted in mature animals with the production of autoimmune disease. While such research has improved the understanding of those processes operative in overt autoimmunity, it has not been informative in relation to events associated with the establishment of self tolerance. Any description of this state which is to be based on observation will necessitate the use of experimental systems that permit observation of animals during the development of self tolerance.The present experiment entailed intervention approximately one third of the way through the gestation period of fetal lambs. An earlier experiment had established that 54‐day fetal lambs would accept allografts of adult skin. This indicated that the capacity to discriminate between self and non‐self had not been acquired at that age. Fetuses at this stage of gestation were submitted to either partial or total removal of the thyroid gland. The excised tissue was then implanted in nude mice for periods of 5 to 9 weeks. It was subsequently replaced subcutaneously, either in the original donor or in another fetus at a comparable stage of gestation. At postmortem examination, several weeks later, self implants in lambs from which the thyroid gland had been completely removed displayed autoimmune thyroiditis of varying degrees of severity. However, self implants in partially thyroidectomized animals were uniformly free from autoimmune manifestations. This implied that these reactions had not been directed against contaminating murine tissues in the implants replaced in completely thyroidectomized lambs. All allogeneic implants were subject to vey heavy lymphocytic infiltration, usually with accompanying necrosis consistent with allograft rejection. This was taken as an indication that hypothyroid fetal lambs had become immunocompetent by the time of thyroid reimplantation. Spontaneous immunological reactivity against reimplanted self thyroid tissue by thyroidectomized lambs was interpreted as a failure to acquire the capacity for self recognition as a result of antigen deprivat

ISSN:0014-2980    

DOI:10.1002/eji.1830190806

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe inhibitory effect of the highly effective drug staurosporine on the early activation signal Ca2+flux was investigated via multiparameter flow cytometry in human peripheral blood T lymphocytes. Staurosporine has been reported to be a specific inhibitor of protein kinase C. However, we show that it inhibits the Ca2+influx in anti‐CD3 and phytohemagglutinin‐stimulated human CD4+and CD8+lymphocytes at concentrations between 1.0 and 10.0 ng/ml. Staurosporine decreases the number of Ca2+‐positive CD4+and CD8+lymphocytes as well as the Ca2+influx per cell; the drug also delays the time of the maximum response to polyclonal stimulation. In addition, we demonstrate that staurosporine affects the primary Ca2+response via inhibition of the release of the membrane‐bound Ca2+from the endoplasmic reticulum in CD4+and CD8+lymphocytes. Binding studies of the anti‐CD3 antibody to T lymphocytes indicate normal binding capacities in the presence of staurosporine. With respect to the classical scheme of T cell activation via phospholipase C, our data suggest that staurosporine may inhibit T cell activation primarily by its effect on the early Ca2+fl

ISSN:0014-2980    

DOI:10.1002/eji.1830190807

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractClass switch of immunoglobulin from μ to γ occurs by recombination between two repetitive switch sequences: Sμand Sγ. However, there are no such sequences in the μ‐δ introns of human and mouse genomes. Although the frequency of IgD‐secreting cells is extremely low in mouse about 1% of patients with myeloma produce IgD in human. In a previous report (Nucleic Acids Res.1988.16: 9497) we reported that a 442‐bp DNA sequence located in the JH‐μintron (defined as σμ) was inserted into the μ‐δ intron (defined as σμ) in the human genome. There is no such insertion in mouse. We analyzed Ig H chain gene loci of two human IgD myelomas: one was analyzed by cloning and sequencing and the other by Southern hybridization. We found that recombination had occurred between these two homologous DNA sequences, resulting in loss of the DNA segment from σμto σμOn the other hand, in a Burkitt lymphoma, Daudi, the DNA fragment from σμto σμwas duplicated. These results suggest that homologous recombination between σμand σμsequences mediates class switch from μ to δ in human and that it occurs via unequal crossing‐over between sis

ISSN:0014-2980    

DOI:10.1002/eji.1830190808

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractFollowing the i.p. injection of casein, rats showed increased serum levels of C4 and C3. C4 levels peaked on day 2 and returned to normal by day 4, while C3 levels peaked on day 3 before returning to normal on day 4. These changes were paralleled by changes in the hepatocyte synthesis rates of these two proteins.Macrophages, isolated from the peritoneal cavities of rats on days 1 to 7 (day‐1 to day‐7 macrophages) following i.p. injection of casein, were culturedin vitro, and the peritoneal macrophage‐conditioned media (PMCM) assayed for their abilities to stimulate synthesis of C4 and C3 by hepatocytes from control rats. Day‐2 PMCM selectively stimulated synthesis of C4, while day‐3 and day‐4 PMCM selectively stimulated C3 synthesis. These activities were called C4‐hepatocyte stimulating factor (C4‐HSF) and C3‐HSF, respectively.The addition of anti‐interleukin (IL) 1, tumor necrosis factor (TNF)‐α, TNF‐β, IL 6 or interferon (IFN)‐γ antibodies to day‐2 PMCM did not affect C4‐HSF activity, and none had any effect on C3‐HSF activity in day‐4 PMCM. However, the addition of anti‐IL 1 to day‐4 PMCM resulted in the re‐expression of C4‐HSF activity as well as loss of thymocyte proliferative activity. C4‐HSF activity could also be detected in day‐4 PMCM by separating it from IL1 activity using gel filtration chromatography. Furthermore the addition of recombinant IL1β to day‐2 PMCM prevented the expression of C4‐HSF activity. Thus IL 1 appears to play a regulatory role in the acutephase response in the rat, by preventing the expression of C4‐HSF activity.The identities of C4‐HSF activity and C3‐HSF are still unknown but we believe that C3‐HSF activity could be IL 6 as it has a similar molecular weight (30 kDa) and purified human IL 6 was more effective than IL 1, TNF‐α or TNF‐β in stimulating C3 synthesis by rat hepatocytes. C4‐HSF activity appears to be a property of a previously u

ISSN:0014-2980    

DOI:10.1002/eji.1830190809

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractElevated temperatures and a number of other types of stress induce synthesis of a small number of highly conserved proteins, the heat shock proteins, in a wide variety of cells. The structure and regulation of these proteins have been intensively studied but the question of the function of this universal response has remained unanswered. We studied the effect of heat shock on tumor necrosis factor‐α (TNF‐α)‐ and ‐β (TNF‐β)‐mediated cytolysis of WEHI‐164 clone 13 target cells. One hour pretreatment of target cells at 42°C decreased rTNF‐α‐mediated lysis by 65.3%, 50.5% and 44.8% and TNF‐β‐mediated lysis by 61.9%, 43.2% and 38.9% at cytokine concentrations of 0.5 ng/ml, 5 ng/ml and 50 ng/ml, respectively, in an 18‐h Cr‐release assay. The effect was maximal when TNF‐α was added 1 h after the heat shock and then gradually declined, being almost undetectable after 2 days. This pattern was found to roughly coincide with the kinetics of hsp68, the major heat‐induced protein in murine cells. Heat shock treatment had no protective effect when given 1 h after addition of recombinant TNF‐α. The heat‐induced target cell resistance was not associated with decreased binding of recombinant TNF‐α to its receptor. Inhibition of protein synthesis by cycloheximide diminished this effect by 76% and inhibition of transcription by actinomycin D abolished it completely, suggesting thatde novosynthesized, heat‐induced proteins protect target cells from TNF

ISSN:0014-2980    

DOI:10.1002/eji.1830190810

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractThe lymphokine interleukin (IL) 4 plays a crucial role in the regulation of IgE synthesis. In the present study, the cellular and cytokine requirements for the IL 4‐dependent induction of IgE synthesis in humans were analyzed. Recombinant IL4 could induce IgE synthesis by peripheral blood mononuclear cells and autologous T/B cell mixtures, but not by highly purified B cells. IgE induction by IL4 was strongly decreased in monocyte‐depleted peripheral blood mononuclear cells. These results show that the induction of IgE synthesis by recombinant IL 4 is T cell dependent and optimal in the presence of monocytes. IL5 and IL6, but not IL2, IL1 and tumor necrosis factor‐α, strongly up‐regulated the IL4‐dependent synthesis of IgE, with modest effects on cell proliferation. An anti‐IL6 polyclonal antibody strongly inhibited IL4‐driven IgE production. Endogenous IL6 plays, therefore, an obligatory role in the IL4‐dependent induction of IgE. However, a combination of IL 4, IL 5 and IL 6 (with or without IL 1) at optimal concentrations could not induce IgE synthesis by purified normal B cells, indicating that cytokine‐mediated signals, although essential, are not sufficient for the IL 4‐dependent induct

ISSN:0014-2980    

DOI:10.1002/eji.1830190811

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY