摘要:

Experimental models of autoimmunity in the rat may feature selective activation of either the Th1 or Th2 subset of helper T cells. Interleukin‐12 (IL‐12) is a key cytokine in the development of Th1 responses. In order to study IL‐12 in the rat we used polymerase chain reaction (PCR) primers based on murine IL‐12 to amplify a partial cDNA from rat tissue. The product was cloned and sequenced: it shows 94% nucleotide identity with the murine gene and 94% identity of predicted amino acid sequence. Primers based on the rat IL‐12 sequence were used to analyse IL‐12 expressionin vivousing semi‐quantitative PCR. We studied RNA from lymphoid tissues of two rat strains which differ in their response to mercuric chloride (HgCl2): Brown Norway (BN) rats develop autoimmunity with a predominant Th2 response; Lewis rats are resistant. Interleukin‐12 expression was higher in Lewis than BN, and higher in spleen than lymph node. After HgCl2, IL‐12 expression increased in BN towards the time when the autoimmune response autoregulates. Variation in baseline levels of IL‐12 expression may account for the Th2 predisposition of BN rats compared to Lewis rats; IL‐12 may play a role in the autoregulation of the Th2 res

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-279.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

Oestrogens can regulate immune functions, and due to this females have more effective immune responses than males. Oestrogens and anti‐oestrogens enhance T‐cell‐dependent antibody production of B cellsin vitro. The cytokine mediators which are behind oestrogen and anti‐oestrogen induced effects are not yet known. The authors studied whether anti‐oestrogens (tamoxifen and toremifene) can regulate PMA‐induced cytokine production of B‐, T‐or myeloid cell lines. Anti‐oestrogens, tamoxifen and toremifene, stimulated overall cytokine production on a B‐cell line (Ball), whereas on a T‐cell line (Molt‐4) tamoxifen stimulated IL‐1β, IL‐6 and IFN‐γ production and toremifene inhibited it. Anti‐oestrogens did not have any significant effect on cyt

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-85.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

The concept that activation of MHC class I‐restricted CD8+cells entirely depends on help from MHC class II‐restricted CD4+T cells has recently been supplemented with an alternative model in which CD8+cells can directly be activated by MHC class I‐expressing professional antigen‐presenting cells (APC), which are able to deliver an accessory signal. The authors analysed the role of CD28‐mediated costimulation for T helper cell‐independent activation of purified human CD8+T cells in two differentin vitromodels. Freshly isolated CD8+cells could be activated (proliferation, IL‐2 production and cytotoxic activity) by anti‐CD3‐presenting FcγR+mouse cells transfected with the human CD28 ligand, CD80, as the only accessory signal. On the other hand, activation of CD8+cells by allogeneic MHC class I on EBV‐transformed B cells, which express two different CD28 ligands, CD80 and CD86, also proceeded very efficiently (proliferation, cytotoxic activity and CD25 expression), but was either not, or only partially, blocked by anti‐CD80 and anti‐CD86 MoAb or CTLA‐4Ig. This indicates that other costimulatory signals are also effective, and that CD28 triggering is not absolutely required for initial T‐cell activation. CsA and CD80/CD86‐blocking agents were synergistic in completely inhibiting activation of CD8+cells in the MLR with allogeneic B‐cell lines. This combination also induced non‐responsiveness of CD8+cells upon restimulation in the absence of blocking agents. Therefore, although professional APC can apparently provide multiple costimulatory signals for direct activation of CD8+T cells, the signal derived from CD80/CD86 is

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-82.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

The expression of the receptor for the anaphylatoxin C5a (C5aR, CD88) on the human mast cell line HMC‐1 was studied with four anti‐C5aR monoclonal antibodies directed to the N‐terminal domain of the receptor. All antibodies bound to the human mast cell line HMC‐1. The binding could be blocked by recombinant C5a and by peptide EX‐1 representing amino residues 1–31 on the N‐terminal domain of the C5aR. In addition, FITC‐labelled C5a bound to HMC‐1, and this binding could be blocked by unlabelled C5a or C5aR antibodies. C5aR‐specific mRNA was detected in HMC‐1 cells by RT‐PCR which confirmed the expression of the C5aR gene made by these cells. Lymphocyte‐conditioned medium, interferon‐γ or phorbol esters which have been shown to induce a down‐regulation of C5aR on myeloid cells did not influence the expression of C5aR on HMC‐1. C5a let to a transient mobilization of intracellular calcium in HMC‐1 which could be inhibited by pre incubation of C5a with a C5a‐specific antibody. In contrast to findings with granulocytes, HMC‐1 did not respond to C5a(desArg), confirming previous findings with human skin mast cells. The findings show that (i) although HMC‐1 differ from granulocytes in their responsiveness to C5a(desArg), they express similar C5aR and (ii) HMC‐1 resemble skin mast cells in the expression and function of C5aR and may therefore serve as a model in future studies addressing the biology of this

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-272.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

The CD45 glycoprotein isoforms exhibit a receptor‐like composition and display intracellular protein tyrosine phosphatase (PTPase) activity. The present study links CD45 to the regulation of L‐selectin (CD62L), a leucocyte glycoprotein important for extravasation and homotypic aggregation. Monoclonal antibodies (MoAbs) IOL1b and AICD45.2, but not GAP8.3, all of which are directed against common CD45 epitopes, were found to elicit lymphocyte L‐selectin down‐regulation. Lymphocyte L‐selectin down‐regulation in response to anti‐CD45 MoAbs was enhanced by high cell density and partially antagonized by the protein tyrosine kinase (PTK) inhibitor, herbimycin A. The MoAbs IOL1b, AICD45.2 and GAP8.3 recognized granulocyte‐expressed CD45 but did not induce loss of L‐selectin expression of granulocytes. In contrast, the CD45 PTPase inhibitor, vanadate, induced L‐selectin down‐regulation both in lymphocytes and granulocytes. The PTPase activation by nitric oxide (NO) or the NO‐generating compound, sodium nitroprusside, did not affect L‐selectin surface expression. Increased concentrations of soluble L‐selectin were detected after anti‐CD45 or vanadate‐induced down‐regulation of L‐selectin surface expression. While activation of protein kinase C (PKC) by phorbol 12‐myristate 13‐acetate (PMA) induces rapid L‐selectin down‐regulation of L‐selectin surface expression in both lymphocytes and granulocytes, the PKC inhibitor, H 7, was also found to down‐regulate lymphocyte and granulocyte L‐selectin surface expression. The inhibitor H 7 synergized with vanadate in down‐regulating lymphocyte L‐selectin surface expression, but partially inhibited vanadate‐induced granulocyte L‐selectin down‐regulation. The results suggest that in a cell type‐specific fashion the PKC system and tyrosine phosphorylation and dephosphorylation cascade

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-282.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

To investigate the regulation of interleukin‐2 (IL‐2) responsiveness of T cells, a human CD4+ T‐cell clone with constitutive expression of IL‐2 receptors was stimulated with recombinant IL‐2 (rIL‐2) in the presence or absence of immobilized anti‐CD3 monoclonal antibodies (αCD3immMoAb). Incubation of T cells with αCD3immMoAb decreased IL‐2‐induced proliferation which could not be ascribed to the modulation of IL‐2 receptor expression nor to cell death. Phorbol‐myristate‐acetate (PMA), an activator of protein kinase C (PKC), also induced down‐regulation of IL‐2 responsiveness. The αCD3solMoAb, inducing Ca2+‐mobilization without activating PKC, did not inhibit IL‐2 responsiveness whereas cyclosporine A (CsA), a drug that inhibits the Ca2+‐dependent activation pathway, did not prevent the induction of IL‐2 hyporesponsiveness induced by αCD3immMoAb. It is concluded that modulation of IL‐2 responsiveness of T cells via the T‐cell receptor/CD3 complex (TCR/CD

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-280.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

LAMA‐84, a human leucocytic cell line, which upon establishment was described as having megakaryocytic, erythroid and granulocytic characteristics, was analysed for expression of various differentiation markers. In addition to some of the previously described phenotypic characteristics, this cell line was found to express mRNA for several proteins characteristic for basophilic leucocytes and mast cells. The authors show that LAMA‐84 cells express mRNA for the mast cell tryptase, the proteoglycan core protein, carboxypeptidase A and the α and β chains of the high affinity IgE receptor (FcεRI). The authors examined the potential of LAMA‐84 to differentiate in serum‐free medium or after DMSO or PMA treatment. Depending on the inducing factor, surface expression of the FcεRI α‐chain was increased from 20% to 35–50% of the cells and mRNA levels for tryptase were increased in serum‐free medium and after DMSO treatment. LAMA‐84 was found to express CD13, CDw17, CD29, CD33, CD40, CD45 and CD117. Furthermore, mRNA for the eosinophil/basophil markers Charcot–Leyden crystal (CLC) protein and the major basic protein (MBP), as well as the erythrocyte differentiation marker α‐globin, was detected. However, the authors observed only trace amounts of mRNA for another erythroid differentiation marker (glycophorin), trace amounts of the megakaryocytic marker GPIIIa, and no detectable level of GPIbα. By comparing the expression pattern of a panel of differentiation markers in LAMA‐84, and a second human cell line (KU812) expressing a basophil phenotype, it is evident that these cell lines, which presently are the only two cell lines identified with basophilic characteristics, share a large number o

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-84.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

CD73 is a bifunctional glycosyl phosphatidylinositol anchored leucocyte differentiation antigen which has specific ecto‐5′‐nucleotidase (ecto‐5′‐NT) activity and is an accessory T‐lymphocyte activation molecule. The aim of the present study was to investigate the CD73 expression on blood mononuclear cells (BMC) from a group of patients with primary immunoglobulin deficiency (IGD). This group of patients had both significantly decreased levels of ecto‐5′‐NT on BMC (P = 0.002) and decreased numbers of CD73 molecules per CD73+lymphocyte (P = 0.01). Five of the 10 patients had a decreased percentage of CD73+lymphocytes. Among B‐lymphocytes the patients had normal percentages of CD73+cells but four of the 10 patients had numbers of CD73 molecules per CD73+B‐lymphocyte below the normal range. Among CD4‐lymphocytes three out of 10 patients had percentages of CD73+below the normal range and four out of 10 patients had decreased percentages of CD73+CD8‐lymphocytes. Significant correlations were found betweenin vitroproliferative responses to mitogens and the number of CD73 molecules per CD73+lymphocyte (rs = 0.60,P < 0.01) and per CD73+CD8‐lymphocyte (rs = 0.64,P < 0.02). In addition, a positive correlation was found between ability to proliferate and level of ecto‐5′‐NT on BMC (rs = 0.53,P < 0.05). Furthermore the ability of BMC to synthesize ecto‐5′‐NT was studied. During 2 days' culture ecto‐5′‐NT activity increased markedly on BMC from both patients and healthy donors. The level of activity on BMC from all patients attained levels higher than on freshly isolated BMC from healthy donors. This shows that the decreased levels of ecto‐5′‐NT found on freshly isolated B

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-281.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

In the present study the authors investigated the T‐cell response to different enterobacteria orHelicobacter pyloriand tested the hypothesis that the frequency of bacteria‐specific T cells is increased in the intestine of patients with active inflammatory bowel disease (IBD), i.e. Crohn’s disease (CD) and ulcerative colitis (UC). The analysis of a large panel of T‐cell clones (Tc) (n = 888) from peripheral blood, non‐inflamed and inflamed intestine from IBD patients and control individuals shows that both peripheral blood and intestinal T‐cell clones were selectively stimulated by eitherSalmonella typhimuriumYersinia enterocolitica03,Escherichia coliorHelcobacter pylorisonicates, that only< 3% of all bacteria‐reactive Tc were crossreactive and that proliferation to bacterial sonicates was inhibited by anti‐MHC class II antibody. In addition, bacteria‐specific Tc from IBD patients were more frequently isolated from inflamed intestine than from peripheral blood (P = 0.0039) or non‐inflamed intestine. These data, from a large number of T‐cell clones, are the first systematic analysis describing the response of individual T cells towards different bacterial species (ssp.). They show that T cells with specificity for distinct antigens or superantigens that are characteristic for a defined bacteria ssp. are present in normal, and increased in inflamed, IBD‐intestine. These bacteria‐specific Tc

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-273.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

Chemokines, which include interleukin (IL)‐8, are a family of pro‐inflammatory molecules with potent chemoattractant activity on neutrophils, as well as other cell types. IL‐8 can be recovered from many inflammatory sites. To test the hypothesis that Th2‐type allergen‐specific T cells, known to be the main cell type governing the allergic inflammation, are a source of IL‐8 and to investigate whether IL‐8 release is influenced by the nature of thein vitromitogenic or co‐mitogenic stimulation, cypress‐specific T‐cell clones (TCC) were generated from five allergic subjects duringin vitroseasonal exposure to the allergen. Purified cypress extract was produced directly from freshly collected pollen and used forin vitrostimulation of PBMC bulk cultures. After 5 days priming and a further 7 day period of IL‐2‐driven cell expansion, monoclonal antibodies to CD3, CD2 and CD28 were adopted forin vitrorestimulation of allergen‐specific cell lines or, subsequently, secondary established TCC. The induction of apoptosis was detected by propidium iodide (PI) cytofluorimetric assay. Basal and co‐stimulation‐induced IL‐8 production was measured by an ELISA method. Both cypress‐specific T‐cell lines and TCC secreted appreciable amounts of IL‐8. By cross‐linking T‐cell lines or Th2 CD4+TCC with CD3, CD2 or CD28 MoAbs, the authors observed a great stimulation‐induced IL‐8 secretion, preferentially after CD2 or combined CD2/CD28 stimulation. In addition, CD4+clones released large amounts of IL‐8 into culture supernatants after CD2 stimulation while undergoing programmed cell death (30–40% hypodiploid DNA profile of PI‐stained cells). In contrast, CD3 crosslinking was unable to determine the release of IL‐8 or the induction of apoptosis. Taken together, these results suggest that incomplete TcR engagement by allergen may lead to the secretion of pro‐inflammatory cytokines with a contemporary induction of apoptosis in a significant number of target cells. This phenomenon may represent an additional

ISSN:0300-9475    

DOI:10.1046/j.1365-3083.1996.d01-83.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY