摘要:

AbstractWe examined the effect of tebufelone, a dual cyclooxygenase (CO)/5‐lipoxygen‐ase (LO) inhibitor, on the synthesis, secretion and gene expression of interleukin (IL) 1β and tumor necrosis factor (TNF)‐α by human peripheral blood mono‐nuclear cells (PBMC). Basal concentrations of immunoreactive IL 1β and TNF‐α after 18–24 h, in the absence or presence of tebufelone (≤ 12.5 μM), were near the limit of detection (100 pg/ml). By contrast, preincubation (1 h) of cells, in amounts of tebufelone which decrease the formation of leukotriene (LT) B4, markedly enhanced (up to 500%) the synthesis of IL 1β and TNF‐α following lipopolysaccharide (LPS), heat‐killedStaphylococcus epidermidisor concanavalin A stimulation. Moreover, a disproportionate amount of the overall increase in IL 1(α and β) was secreted in contrast to the amount which remained cell associated, an effect unrelated to cell damage or leakage as tebufelone had no effect on either lactate dehydrogenase release by PBMC, or mitochondrial dehydrogenases of adherent monocytes as detected by enzymatic cleavage of the substrate 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐tetrazolium bromide. There was no inverse correlation between the changes in prostaglandin (PG)E2levels and TNF‐α or IL 1β synthesis, and when PG formation was maximally inhibited by preincubating the cells in indomethacin, tebufelone, added 1 h before the stimulus, continued to enhance the synthesis of IL 1β although not that of TNF‐α. The addition of the CO/5‐LO inhibitor 2 h after LPS stimulation, however, did not interfere with IL 1β synthesis, suggesting that tebufelone interacts with an early event(s) in the activation of PBMC. For IL 1β and TNF‐α, basal and stimulated (4 h post LPS) mRNA levels were not increased by tebufelone, despite a concomitant increase in the synthesis of IL1β. In conclusion, we have demonstrated that tebufelone enhances IL 1(α and β) and TNF‐α synthesis at concentrations which suppress leukotriene formation. These findings argue against a role of 5‐LO products

ISSN:0014-2980    

DOI:10.1002/eji.1830210202

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractMonoclonal antibodies (mAb) identifying the CD5 antigen were used to stimulate human peripheral blood T lymphocytes. Three out of three anti‐CD5 mAb, 10.2, OKT1 and anti‐Leu‐1 induced vigorous proliferation of purified T cells in the presence of 1.6 nM phorbol 12‐myristate 13‐acetate (PMA). Immobilization of anti‐CD5 mAb on a solid support was necessary for the induction of a proliferative response. Neither 1.6 nM PMA, nor immobilized anti‐CD5 mAb were mitogenic as a sole stimulus. mAb identifying CD4, CD7, CD11a, CD18, and major histocompatibility complex class I molecules were not comitogenic with PMA. Anti‐CD5/PMA‐induced cell proliferation proceeded by an interleukin 2 (IL2)‐dependent mechanism, as was demonstrated by the cell surface expression of the p55 chain of the IL2 receptor (IL 2R), the production of IL2 and the inhibition of the proliferative response by anti‐IL2R mAb anti‐Tac. There was no strict requirement for detectable numbers of monocytes, although cell proliferation could be enhanced by the monocyte‐derived cytokines IL 1 and IL6. Phorbol 12, 13‐dibutyrate and mezerein could substitute for PMA in this activation pathway, but synthetic diacylglycerols and phorbol esters that do not activate protein kinase C (PKC) could not, indicating a need for prolonged activation of PKC. T cells activated by anti‐CD5/PMA are sensitive to inhibition by cyclosporin A (CsA) and by prostaglandin E2(PGE2). This contrasts with anti‐CD28/PMA‐induced Tcell proliferation, which is resistant to CsA and PGE2. Cell surface expression of CD5 was strongly up‐regulated by PMA, whereas CD3 expression was down‐regulated. We conclude that T cell activation can be triggered by engagement of CD5 by immobilized anti‐CD5 mAb, combined with prolonged activation of PKC. These data support a role for CD5 as an

ISSN:0014-2980    

DOI:10.1002/eji.1830210203

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractNeonatal transplantation tolerance was one of the first experimental systems to reveal that tolerance could be achieved to non‐self antigens in living animals. Functional and direct evidence (obtained by the use of monoclonal antibodies directed at T cell receptors specifically reactive with I‐E molecules) confirm that tolerance is achieved, at least in part, via clonal elimination of developing thymocytes. In this report, we show that induction of tolerance of class I alloantigens in neonatal mice is governed by expression of I‐E molecules. Neonatal I‐E non‐expressor mice proved to be highly resistant to the acquisition of class I tolerance if the donor inoculum expressed disparate class I antigens as well as I‐E molecules. The spleens of the few class I‐tolerant, I‐E non‐expressor mice that were generated were found to be depleted of I‐E‐reactive (RR315+) T cells, whereas no such depletion was observed in their neonatally injected, but non‐tolerant littermates. By contrast we found no resistance to tolerance of I‐A alloantigens when neonatal I‐E non‐expressor mice received injections of I‐A‐disparate, I‐E‐bearing donor cells. In these tolerant mice, splenic I‐E‐reactive T cells were readily detected in apparently normal amounts. These results indicate that lack of I‐E expression in newborn mice confers resistance to tolerance induction to class I alloantigens, especially when the latter are expressed on donor cells that also display I‐E molecules. The possible mechanisms operating to produce resistance to tolerance induction in neonatal mice are discussed, including the possibilities that (a) I‐E may act as a restricting element during tolerance induction (an ontogenic process), and (b) the expression of I‐E on H‐2‐disparate, I‐E‐expressing test skin allografts may provide a source of “help” fo

ISSN:0014-2980    

DOI:10.1002/eji.1830210204

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe mechanism of induction of anti‐Sm antibodies by passive transfer of anti‐Sm mAb in MRL/lpr mice was investigated. No idiotypic relationship was detected between the inducing monoclonal antibody KSm2 and either the induced circulating anti‐Sm antibodies or the products of anti‐Sm‐producing hybridomas derived from spleen cell fusion of treated mice. Treatment of mice with ribonucleoprotein Sm antigen, alone or as an immune complex, induced anti‐Sm and anti‐ribonucleoprotein antibodies similarly to treatment with KSm2. This suggests that autoantigen contributes to the development of the anti‐Sm respo

ISSN:0014-2980    

DOI:10.1002/eji.1830210205

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe ability of CD4+T cells from CBA/Rij mice to produce interleukin (IL) 2 after stimulation with anti‐CD3, concanavalin A, or the combination of phorbol 12‐myristate 13‐acetate and ionomycin declines during aging. This phenomenon was accompanied by an increased production of IL 4 and interferon‐γ. These age‐related changes in lymphokine production correlated with the decrease in the percentage of CD45RBhiCD4+T cells from about 80% in 2‐month‐old to about 40% in 27‐month‐old mice. This phenotypic shift was responsible for the decline in IL 2 production, because in young and in old mice CD45RBhiCD4+T cells were more potent IL 2 producers than CD45RBlocells. Moreover, old CD45RBhiCD4+T cells produced less IL 2 than their young counterparts. Proliferative responses by T cells from old mice were lower than those of young mice, regardless whether the cultures were supplemented with IL 2, IL 4 or both lymphokines. As far as CD4+T cells were concerned, this hyporesponsiveness was found in the CD45RBloas well as in the CD45RBhiCD4

ISSN:0014-2980    

DOI:10.1002/eji.1830210206

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe ileal Peyer's patch (PP) was selectively labeled with fluorescein isothiocyanate by extracorporeal perfusion in 7–12 week‐old lambs and the lymphocyte linege and fate of the emigrants was determined by fluorescence microscopy and flow cytometry. PP emigrants were found in all tissues examined, accounting for 10%–15% of ileal mesenteric lymph node (MLN), 1%–2% of jejunal MLN, jejunal PP, prescapular lymph node (PLN) and 3%–4% of spleen cells. All ileal PP emigrants enter the ileal MLN on their way to the circulation. Removal of the MLN prior to perfusion enabled emigrants to go directly to the circulation and extravasate in distant tissues faster than in intact animals. The ileal MLN might provide an additional level of regulation for ileal PP emigrants. The perfused ileal PP contained about 25 times more B cells than T cells. The emigrant cells found in different tissues included both T and B cells but came to reflect, although to a lesser degree, the B cell composition of the tissue from which they were derived. One day after perfusion the composition of PP emigrants was similar to that of the tissue within which they were found; the spleen was the exception with a bias towards B cells. By day 3 the ratio of B to T cells in the PP emigrants was 1 for jejunal MLN and PLN, 1.5 for ileal MLN and jejunal PP, and 4–5 for the spleen and blood. It was concluded that the PP‐derived T cells were recirculating T cells that were in the ileal PP at the time of perfusion. These cells emigrated rapidly and equilibrated such that they accounted for about 1.5% of the T cell pool in various tissues. Most PP‐derived B cells were probably produced in the PP. The greatest contribution (24.4%) that ileal PP emigrants made to the B cell pool of a tissue was with the ileal MLN through which they are obliged to pass. The contribution was lower but still very significant in blood (8.9%), spleen (6.8%), PLN (3.9%), jejunal MLN (3.5%) and jejunal PP (1.8%). There was no evidence that ileal PP emigrants made a greater relative contribution to either T or B cell populations in MLN or jejunal PP than to non‐gut‐associated sites. The B cells were distributed throughout the immune system, which is in accordance with the proposal that the ileal PP is a site of primary B ce

ISSN:0014-2980    

DOI:10.1002/eji.1830210207

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effect of UV radiation on the accessory activities of B lymphoblastoid cell lines (B‐LCL) was investigated in three types ofin vitroT lymphocyte proliferation assay, each of which differed in its accessory requirements. In contrast to monocytes whose accessory function was universally sensitive to UV radiation, B‐LCL were resistant to UV in oxidative mitogenesis and staphylococcal enterotoxin B assays, in which stimulus processing was not a requirement. Expression of membrane interleukin (IL) 1 and HLA‐DR antigens by B‐LCL and monocytes was not affected by UV, nor was surface membrane expression of intercellular adhesion molecule‐1 (ICAM‐1) on B‐LCL. These results were in marked contrast to monocytes in which there was a>65% reduction in ICAM‐1 expression. When UV‐irradiated B‐LCL were employed as antigen‐presenting cells for tetanus toxoid‐dependent T cell stimulation, a reduction in antigen‐presenting function was observed. However, pulsing of B‐LCL with tetanus toxoid prior to UV irradiation preserved their antigen‐ presenting capacity in this system also. These findings indicate that there is differential UV sensitivity among accessory cells which may be explained by different effects of UV radiation on antigen processing and

ISSN:0014-2980    

DOI:10.1002/eji.1830210208

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractDermal and mucosal lymphocyte infiltrates in patients with lichen ruber planus and chronic graft‐vs.‐host disease exhibited reactivity with anti‐fibronectin antibodies. This reactivity was associated with the lymphocytes and localized pericellularly. In contrast, biopsy areas outside lymphocyte accumulations were relatively devoid of reactivity with anti‐fibronectin antibodies. Furthermore, the corresponding biopsies from healthy individuals or patients without lymphocyte infiltration showed negligible reactivity with anti‐fibronectin antibodies. The fibronectin associated with infiltrating lymphocytes in biopsies may be exogenous of non‐lymphoid origin. However, another possibility suggested byin vitroexperiments is that this fibronectin is lymphocyte derived. Thus, during cultivationin vitrolymphocytes appear to synthesize a component with fibronectin‐like properties. Furthermore, a prerequisite for detection of this synthesis was that the cells were cultured in the presence of serum depleted of fibronectin. These results point to the possibility that fibronectin may play a role for lymphocyte interactions with tissues during infiltrat

ISSN:0014-2980    

DOI:10.1002/eji.1830210209

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractA large fraction of naturally activated B cells in the neonate displays degenerate specificity, including reactivity with autoantigens. Transgenic mouse models of autoreactive B cells are mainly concerned with monospecific B cells of high avidity, and the fate of naturally activated autoreactive B cells is still a matter of debate. To pursue this question further, we chose an IgM autoantibody with a recurrent idiotype (Id),i.e.Sp6, because transgenic mice expressing this IgM also were available. In a first approach monoclonal antibodies (mAb) derived from untreated, antigenically stimulated and transgenic mice were used to test whether there were indications for deletion or for Id regulation of naturally activated autoreactive B cells.Over 90% of thymus and spleen cell derived hybridomas from 6‐day‐old Sp6‐transgenic mice were trinitrophenyl (TNP) reactive, carried the Sp6‐Id and bound to a panel of self antigens, including mouse albumin. We failed to obtain B cell hybridomas from the thymus of 28‐day‐old Sp6‐transgenic mice. Furthermore, we could not detect any mAb carrying an anti‐Sp6 Id, but Sp6 did weakly bind to itself. About 25% of mAb derived from control mice displayed degenerate specificity, the majority of them also were TNP reactive. The Sp6 Id was found at a low frequency and a comparable number of mAb carried an anti‐Sp6 Id. Prenatal manipulation at the antigen level (trinitrobenzenesulfonic acid treatment) led to a transient expansion of TNP‐ and autoreactive mAb. The number of mAb carrying the Sp6 Id was not increased, but mAb carrying an anti‐Sp6 Id were observed at high frequency. Those mAb also displayed degenerate specificity.Since Sp6‐transgenic mice were perfectly healthy, it is concluded that this particular autoreactive antibody of degenerate specificity cannot be harmful for the developing organism, which may possibly be due to its self‐binding capacity. Furthermore, some process of down‐regulation was indicated by the absence of B cells expressing the transgene in the thymus of young adult mice. Autoreactivity of untreated and prenatally antigen‐treated mice was, in addition, regulated at the Id level. In particular, mAb recognizing the Id of Sp6 were significantly expanded in antigenically stimulated mice. The data were interpreted in the sense that autoreactive B cells appearing early during ontogeny were rather strictly controlled either by (functional) clonal deletion

ISSN:0014-2980    

DOI:10.1002/eji.1830210210

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe ability of immune complexes (IC) to regulate B lymphocyte differentiation was investigated. Using anin vitromodel, we previously demonstrated that macrophages (MΦ) or lymphoid dendritic cells pulsed with IC differentially regulated B cell function, inducing unresponsiveness or stimulation, respectively. The capacity of MΦ to induce unresponsiveness was dependent upon two signals, an antigen‐specific one supplied by the IC and MΦ‐secreted prostaglandin (PG)E2. Total inhibition of antibody production was never achieved as a small percentage of B lymphocytes were resistant to IC‐induced unresponsiveness. In this study, utilizing an accessory cell‐free system, we demonstrate that splenic B cell fractions separated on Percoll density gradients are heterogeneous in their sensitivity to IC‐mediated unresponsiveness. Small resting B lymphocytes are exquisitely sensitive to IC‐mediated negative signaling and exhibit virtual total ablation of antibody responses. Conversely, large activated B cells are more refractory to this inhibitory pathway. PGE2and other agents which elevate cAMP potentiate IC‐induced unresponsiveness in resting, but not activated B lymphocytes. In addition treatment of resting B cells with PGF2α, which did not elevate cAMP, failed to sensitize these cells to IC‐mediated negative signaling. Unresponsiveness induced by IC is selective for specific aspects of B lymphocyte activation, since B cell differentiation but not proliferation is affected. Furthermore, pre‐treatment of resting B lymphocytes with interleukin 4 prevents the IC‐induced ablation of IgM antibody responses. Overall, our results indicate that the binding of IC by resting B lymphocytes provides a potent mechanism for inhibiting differentiation without affecting proliferation. These observations suggest thatin vivo, IC play an important role in regulating the memo

ISSN:0014-2980    

DOI:10.1002/eji.1830210211

出版商:WILEY‐VCH Verlag GmbH    

年代:1991

数据来源: WILEY