摘要:

AbstractRegulation of interleukin (IL)‐4 production, but not IL‐2 production, was found to be quite different in either freshly isolated T cells or T cell clones. Both fresh T cells and T helper 2‐like clones produced IL‐4 when stimulated with anti‐CD2 in combination with anti‐CD28. However, whereas T cell clones showed enhanced IL‐4 production when phorbol 12‐myristate 13‐acetate (PMA) was used in addition to anti‐CD2 and anti‐CD28, IL‐4 production by fresh T cells was inhibited by the presence of PMA. Prestimulation of fresh T cells led to the following observations: (a) activation in the absence of PMA led to a reversal of the PMA effect and (b) within 2 days these cells resembled T cell clones in that IL‐4 production was no longer inhibited by PMA. When prestimulation was carried out in the presence of PMA, the inhibition of IL‐4 production seemed irreversible. Removal of PMA after 3 days did not lead to renewed capability of IL‐4 production, whereas IL‐2 production was unimpaired. Our data show that the capacity of cultured T cells to produce IL‐4 is determined and fixed during

ISSN:0014-2980    

DOI:10.1002/eji.1830230102

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractThe fifth component of complement (C5) is a self antigen expressed in serum of normal mice at a concentration of about 50 μg/ml. We have previously shown that C5 is constitutively processed and presented by antigen‐presenting cells (APC) in normal mice to induce and maintain complete tolerance in major histocompatibility complex (MHC) class II‐restricted T cells. This report addresses the question of whether C5 presentation involves exogenous antigen which has been internalized for processing or whether intracellular, biosynthesized C5 is being presented with MHC class II. Macrophages were found to synthesize, but not secrete C5 in bone marrow chimeras made from irradiated C5‐deficient [C5(−)] hosts reconstituted with C5‐sufficient [C5(+)]bone marrow [C5(+) ← C5(−)]. In these mice, macrophages are the only source of C5. [C5(+) ← C5(−)]chimeras are not tolerant of C5 and generate C5‐specific T and B cell responses upon immunization indistinguishable from those of C5(‐) mice. Macrophages from [C5(+) ← C5(‐)] chimeras are unable to activate C5‐specific T cell hybridsin vitrounlike macrophages from a C5(−) strain that has matured in a C5‐expressing environment [C5(−) ← C5(+) chimeras]. This shows that under physiological conditionsin vivointracellular C5 does not get access to the class II presentation pathway and thus, does not induce tole

ISSN:0014-2980    

DOI:10.1002/eji.1830230103

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractIn the mouse, conventional B cells are continuously generated from precursor cells located in the bone marrow (BM), whereas the small subset of B‐1 cells (formerly called Ly‐1 B cells) constitute a self‐replenishing population of cells. Here we studied the kinetics of murine peritoneal B‐1a cells(i.e.B‐1 cells expressing CD5). The actual number of B‐1a cells in the peritoneal cavity that are proliferating, as detected by metaphase arrest and S‐phase index, was below detection level, indicating that these cells do not divide significantly at this anatomical location. To establish the life‐span of B‐1a cells we used long‐term administration of 5‐bromo‐2′‐deoxyuridine in combination with three‐color immunocytology on cytospin preparations. The renewal rate of peritoneal B‐1a cells was 1.3% per day representing a 50% renewal time of 38 days. Splenic B cells and popliteal lymph node B cells (predominantly conventional B cells) showed an almost identical renewal rate of 1.1% per day. The data show that peripheral B cells from various lymphoid tissues and locations do not differ significantly in their renewal capacity, even though there are difference

ISSN:0014-2980    

DOI:10.1002/eji.1830230104

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractSuppressor T (Ts) hybridomas and interleukin‐2‐dependent T cell lines were established from spleens of mice, which had been rendered unresponsive to experimental allergic encephalomyelitis (EAE) either by mouse spinal cord homogenate or by the synthetic suppressant copolymer 1 (Cop 1). The Ts hybridoma supernatants and the Ts line cells specifically suppressed thein vitroresponse to the encephalitogenic myelin basic protein (BP), as indicated by inhibition of both the proliferation and interleukin‐2‐secretion responses of a BP‐specific T cell line. Moreover, these Ts cells prevented the development of actively induced EAEin vivo. All hybridomas and lines were most effective when injected at the time of disease induction, thus suggesting that they operate as effector suppressor cells, and functionally inhibit encephalitogenic responses. The data presented here suggest that the suppressor cells are stimulated by the protective epitopes included in the BP as well as in the Cop 1 molecules and that they play an active role in the regulation of EAE. The generation of Ts lines and hybridomas, which have been induced by Cop 1, establish the specific stimulation of suppressor cells to EAE as a mechanism underlying the therapeutic activity

ISSN:0014-2980    

DOI:10.1002/eji.1830230105

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractRecently, evidence was presented that natural antibodies (NAb) are a crucial barrier to human cellular engraftment in severely immunosuppressed normal mice(Eur. J. Immunol. 1992.22:197.). In this report we show that normal mouse serum contains low titers of NAb against human cells of blood groups type O (H) and B and high titers against human cells of blood group A. Accordingly, human peripheral blood leukocytes (PBL) of group O (H) and B donors could be grafted successfully into normal BCBA mice (H‐2h/k) following irradiation with high dose total body irradiation (TBI). PBL of blood group type A donors did not engraft in normal mice but could be transplanted without difficulty in B cell‐deficient CBA/N mice which lack NAb, after conditioning with high dose TBI. Treatment of lethally irradiated normal BCBA mice with cobra venom factor (COF), which eliminates the third factor of complement, and liposomes containing dichloromethylene diphosphonate (C12DMP), which eliminates macrophages, resulted in engraftment of human blood group type A PBL. This implies that the NAb barrier for discordant xenogeneic cell transplantation can be abrogated.A method utilizing directly labeled probes and flow cytometry is described for the quantitation in mouse serum of NAb, reacting with human cells. Using sera of H‐2b/kmice we show that murine NAb react with human stem cells, granulocytes, lymphocytes and monocytes of blood group A and only weakly with similiar cells from blood group O (H) and B donors. Sera of H‐2b, H‐2dand H‐2kmice of different ages and microflora possess NAb against human erythrocytes of blood group type A and occasionally demonstrate weak titers against erythrocytes of blood groups B and O (H) and the Rh

ISSN:0014-2980    

DOI:10.1002/eji.1830230106

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractInjection of incomplete Freund's adjuvant (IFA) into the footpads of BALB/c mice induced an acute inflammation. Draining popliteal lymph nodes showed major histocompatibility complex (MHC) class II‐restricted proliferation when challengedin vitrowith recombinantMycobacterium bovis65‐kDa heat shock protein (hsp65). αβ Tcell receptor‐positive, CD4+, hsp65‐specific T cell lines and clones were generated from these lymph nodes, and 87% of clones responded to a P galactosidase fusion protein containing residues 238–573 of human hsp60. Seventy percent of these hsp60‐responsive clones also responded to a synthetic peptide corresponding to residues 412–423 of the mouse hsp60. This peptide also induced significant responses in IFA‐primed lymph node cells but not in lymphoid cells from unimmunized mice.These results demonstrate that T cells specific for epitopes in self hsp60 are activated during inflammatory responses induced in the absence of exogenous bacterial hsp65. The findings of this study may provide a basis for understanding the often reported isolation of mycobacterial hsp65‐responsive T cells from inflammatory sites of arthritis patients, and the protective effects of preimmunization with hsp65 in experimental

ISSN:0014-2980    

DOI:10.1002/eji.1830230107

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractA naturally occurring receptor‐level antagonist of interleukin‐1 (IRAPorIL‐1 ra) has recently been cloned. To determine what stimuli might regulate this inhibitor, cytokines were tested for their effects on the steady‐state level of IRAP mRNA in phorbol ester‐differentiated U937 cells. The cytokines tested fell into one of three groups: (a) inducers: granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), IL‐4, (b) weak inducers (<2‐fold stimulation): [IL‐lα, IL‐Iγ, and transforming growth factor‐β (TGF‐γ)] and (c) cytokines with no effect: (IL‐2, platelet‐derived growth factor, acidic fibroblast grouth factor, basic fibroblast growth factor, epidermal growth factor, granulocyte colony‐stimulating factor, IL‐3, IL‐5, IL‐6, interferon‐y, multi‐colony stimulating factor, tumor necrosis factor ‐a and IRAP itself. One hundred U/ml of either GM‐CSF or IL‐4 was the dose inducing peak IRAP mRNA expression; that peak expression occurred 12 h after addition of cytokine. GM‐CSF induced a 34 ±15‐fold increase in IRAP mRNA, and IL‐4 induced a 15± 6‐fold increase. In the same RNA samples, GM‐CSF increased IL‐ip mRNA 5.9 ± 1.7‐fold, but IL‐4 decreased IL‐Iγ mRNA to half that of control levels (0.45 ± 0.17). Thus, a single stimulus (IL‐4) decreased the expression of an agonist (IL‐1) while it increased the expression of an antagonist (IRAP). When U937 cells were treated with both IL‐4 and GM‐CSF, the level of IRAP mRNA induced was additive, suggesting that the cytokines acted differently to increase IRAP mRNA levels. The level of IL‐1 mRNA in cells treated with both IL‐4 and GM‐CSF was intermediate. Dexamethasone and cycloheximide inhibited all mRNA increases and did not reverse IL‐4‐induced decreases in IL‐1 mRNA. These studies have identified two cytokines which induce IRAP in the monocytic cells studie

ISSN:0014-2980    

DOI:10.1002/eji.1830230108

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractTheiler's murine encephalomyelitis virus (TMEV) produces a chronic, inflammatory demyelinating disease in susceptible mouse strains that is used as a model for multiple sclerosis. Because disease susceptibility correlates temporally with the development of virus‐specific delayed‐type hypersensitivity (DTH) responses, we studied methods and mechanisms by which virus‐specific DTH could be specifically inhibited. The intravenous injection of UV‐inactivated TMEV coupled to syngeneic splenocytes via a carbodiimide linkage (TMEV‐SP), prior to immunization, induced a significant degree of tolerance in virus‐specific helper (Th) cells as determined by decreased DTH and T cell proliferative responses, and decreased interleukin (IL)‐2 and interferon (IFN)‐Y protein and mRNA levels. In contrast to the reduced levels of Thl‐specific lymphokine mRNA levels, IL‐4‐specific mRNA levels in response to virus stimulation were not affected in tolerant mice. Surprisingly, the total anti‐TMEV antibody response in DTH tolerant mice was enhanced 20‐100‐fold over sham‐tolerized controls and was composed of reduced levels of anti‐virus IgG2a, but dramatically increased levels of anti‐virus IgGl. The “split‐tolerance” was antigen specific, dependent on the concentrations of TMEV and carbodiimide used in the coupling procedure, and varied with the number of coupled syngeneic splenocy tes administered. The fixative effects of carbodiimide on antigen‐presenting function were necessary for the induction of DTH tolerance with TMEV‐SP, since intravenous administration of virus coupled to splenocytes via a biotin‐avidin linkage led to enhanced virus‐specific antibody responses, but was unable to inhibit DTH unless concomitantly fixed with carbodiimide. Collectively, the data indicate that Thl cells (mediating DTH, IL‐2 and IFN‐γ production, and helper function for IgG2a production) were specifically anergized, with concomitant stimulation of Th2 cells (producing IL‐4 and m

ISSN:0014-2980    

DOI:10.1002/eji.1830230109

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractWe characterized the defects of CD4+ cells in a 17‐month‐old girl suffering from combined immunodeficiency with hypereosinophilia (Omenn's syndrome). Because the vast majority of peripheral blood CD4+cells expressed the CD45R0 isoform, we purified circulating CD4+CD45R0+cells from the patient and healthy individuals in order to compare their production of cytokines. The patient's CD4+CD45R0+cells spontaneously produced high levels of interleukin‐5 (IL‐5)in vitro(1600 pg/ml after 24 h of culture) and this was associated with the presence of IL‐5 in serum (323 pg/ml). After stimulation with phorbol 12‐myristate 13‐acetate (PMA) and calcium ionophore A23187, they produced higher levels of IL‐4 (306vs.55 ± 4 pg/ml) and IL‐5 (2900vs.213 ± 72 pg/ml) and lower levels of IL‐2 (17 vs. 63 ± 17 IU/ml) and interferon‐γ (IFN‐γ) (16vs.299 ± 70 IU/ml) than controls CD4+CD45R0+cells. This T helper type 2 (Th2) pattern was confirmed by the detection using reverse polymerase chain reaction of IL‐4, IL‐5 and IL‐10 mRNA within peripheral blood mononuclear cells. During a therapeutic trial with human IFN‐γ (40 μg/day) which ameliorated the clinical status of the patient, we observed a down‐regulation of thein vivoexpression of IL‐5 and IL‐10, a normalization of the eosinophil count and an improvement of the Tcell response to phytohemagglutinin. This observation indicates for the first time that Th2‐like cells might be involved in certain forms of congenital immunodeficiency and that IF

ISSN:0014-2980    

DOI:10.1002/eji.1830230110

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY

摘要:

AbstractT lymphocytes may be separated into subsets according to their expression of CD45 isoforms. The CD45R0+T cell subset has been reported to proliferate in response to recall antigen and to mitogenic mAb to a much greater extent than the CD45RA+subset. This difference could be due to more efficient coupling of the T cell antigen receptor complex to mitogenic signaling pathways. To investigate this possibility, CD3 antigen‐induced calcium signals, diacylglycerol (DAG) production and protein kinase C (PKC) activation levels were compared in CD45RA+and CD45R0+human T lymphocyte subsets derived from peripheral blood. The mean CD3‐induced rise in intracellular calcium was 80% greater in CD45R0+than in CD45RA+cells. Basal DAG levels in CD45R0+cells were found to be, on average, 60% higher than in CD45RA+cells (p= 0.002), but the CD3‐induced production of DAG over background was not different in the two subsets(p= 0.4). Basal PKC activity, and CD3‐induced PKC activation levels over background, were found to be 50% and 140% higher, respectively, in CD45R0+cells than in CD45RA+cells (p= 0.015 and 0.023). The CD45R0+subset contained a higher proportion of cells expressing activation markers, such as CD25, CD71 and major histocompatibility complex class II, when compared to the CD45RA+subset. Our results suggest that the elevated basal DAG levels observed in the CD45R0+subset may reflect the recent activation of these cells. Both the higher basal DAG and CD3‐induced elevation in intracellular calcium observed in the CD45R0+cells may contribute to the greater PKC activation signals triggered by CD3 mAb in this subset. These findings elucidate the greater response of CD45R0+T cells to mitogenic stimuli compared to CD4

ISSN:0014-2980    

DOI:10.1002/eji.1830230111

出版商:WILEY‐VCH Verlag GmbH    

年代:1993

数据来源: WILEY