摘要:

AbstractA mouse monoclonal antibody specific to human IgE (mAb75) was employed to immunize a rabbit to obtain anti‐idiotypes (aId) bearing the internal image of human IgE determinants and reacting with IgE‐binding factors (IgE‐BF) and/or lymphocyte receptors for IgE (FcϵR). mAb75 was selected on the basis of inhibition assays where the binding of mAb 75 to radiolabeled IgE was blocked by IgE‐BF. The latter were produced by a lymphoblastoid cell line (RPMI 8866) expressing FcϵR. Sequential samples of rabbit serum, collected during the immunization period, were extensively absorbed on mouse and human Ig‐Sepharose 4B. The IgG fractions of the rabbit serum displayed the following activities: (a) they reacted with125I‐labeled mAb 75 but not with other labeled mouse Ig including mAb‐aIgE, (b) this binding was inhibited in a dose‐dependent fashion by human IgE but not by other human Ig classes nor by heat‐inactivated IgE, (c) they reacted with a polyclonal rabbit anti‐human IgE and (d) they blocked the binding of125I‐labeled IgE to mAb 75. It was concluded that the rabbit IgG contained aId (RaId) bearing the internal image of heat labile determinants of human IgE. The rosetting of IgE‐coated bovine erythrocytes with FcϵR‐bearing cells was inhibited by preincubating the receptor‐bearing cells with IgG RaId or its F(ab')2but not with normal rabbit IgG. The ability of RaId to react with IgE‐BF as well as with FcϵR was also shown in inhibition experiments where IgE‐BF and solubilized FcϵR blocked the binding of mAb 75 to RaId. Finally, Western blot analysis of human colostrum, known to contain IgE‐BF, indicated that radioiodinated RaId and IgE identified the same 12‐16‐kDa molecules corresponding to IgE‐BF.It is concluded that RaId expresses the internal image of a heat‐labile determinant of IgE which is involved in the binding of IgE to IgE‐BF and FcϵR. An alternative interpretation is that RaId reacts with an idiotypic determi

ISSN:0014-2980    

DOI:10.1002/eji.1830160402

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractIt was possible to define the effects of trehalose dimycolate (TDM), a glycolipid extracted fromMycobacteriurn tuberculosis, on mouse peritoneal macrophages more precisely using endotoxin‐free culture conditions. TDM‐elicited macrophages, when assayedin vitroin the absence of endotoxin, were unable to limit tumor growth; however, after a short treatment (4 h) with low doses of lipopolysaccharide (LPS; 1‐10 ng/ml), they exhibited a strong cytostatic capacity against P815 mastocytoma cells. Thus, TDM injectedin vivodid not activate macrophages fully but it primed them to respondin vitroto low doses of LPS, which provided the final stimulus for activation to antitumor competence. Macrophages elicited by an injection of killed group C Streptococci were also in a primed state; in contrast, thioglycollate‐elicited macrophages were in a nonreceptive state. Besides LPS, concanavalin A (5 μg/ml), MDP (0.2‐1 μg/ml) and the ionophore A23187 (5 μM) can deliver the activation signal to TDM‐primed macrophages.Primed macrophages were found to express several biochemical markers previously described as specific for activated macrophages (low levels of alkaline phosphodiesterase and β‐galactosidase, for example) and, although they were not cytotoxic for tumor cells, they had the capacity to release large amounts of H2O2.However, when pulsed by LPS or MDP, primed macrophages responded by further modifications in their metabolism: the rate of glucose consumption and the labeling of glycoproteins by D‐[2‐3H]mannose were greatly increased and the secretion of a polypeptide of 22 kDa was enhanced. The activation‐associated biochemical markers are thus acquired in two steps. The ability to produce activated oxygen species is expressed earlier than t

ISSN:0014-2980    

DOI:10.1002/eji.1830160403

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractThe property of lipopolysaccharide to induce B cells to both proliferate and differentiate to IgM, IgG3and IgG2bexpression can be ascribed either to a precommitted sequence of molecular events in the activated B cells or, alternatively, to separate activities which independently modulate the two events. To discriminate between these two possibilities we have investigated the relationship between the doses of the polyclonal stimulus and the commitment of the activated cells to proliferate and to produce various isotypes.Low doses of ligand supported proliferation as well as IgM but not IgG2bsecretion. On the contrary, high doses of the same ligand were less efficient in supporting proliferation but strongly induced heavy chain class switch. The effect of lipopolysaccharide concentrations on CHgenes expression decayed with the distance from μ to the respective Cγ gene.Although we could define different B cell subsets on the basis of their proliferative response to various doses of the ligand, all these B subpopulations were found to be multipotential in terms of their switching capacity.Taken together our data show that in lipopolysaccharide cultures B cell proliferation and heavy chain switch are two events completely dissociable on the basis of their inducing requirement

ISSN:0014-2980    

DOI:10.1002/eji.1830160404

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractThe capacity of dendritic cells (DC) and macrophages (MΦ) to present soluble and particulate antigen was tested in an ovalbumin (OVA)‐specific T cell proliferation assay. In a comparative investigation we found that both DC and MΦ, were able to present soluble OVA, but that only MΦ, could present insolubilized OVA to T cells. DC were found to be able to present OVA in collaboration with MΦ. The failure of DC to present insolubilized OVA is probably caused by their inability to endocytose these antigens.DC appeared not to endocytose substantial amounts of soluble OVA either. In contrast to MΦ, antigen presentation by DC is not blocked by lysosomotropic drugs. Taken together, these observations suggest that DC can present soluble protein antigens without intracellular degra

ISSN:0014-2980    

DOI:10.1002/eji.1830160405

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractNormal human B cell proliferation is controlled by various immunoregulatory signals including the T cell‐derived lymphokine B cell growth factor (BCGF). Human BCGF provides the final proliferative signal to normal, activated B cells. We herein show that anti‐CR2 monoclonal antibodies inhibit human B cell responsiveness to purified BCGF. Addition of anti‐CR2 antibody, AB5, was capable of completely inhibiting BCGF‐mediated enhancement of either anti‐μ or staphylococcal protein A‐activated human B cells (191 ± 21 cpmvs.3942 ± 622 cpm, mean ± SEM). Inhibition of B cell response to BCGF by AB5 occurred in a dose‐dependent manner. Monoclonal antibody anti‐B2, which recognizes the same 140‐kDa glycoprotein as AB5, in comparable concentrations also inhibited B cell responsiveness to BCGF. Monoclonal antibodies of the same subclass (IgG1) showed no inhibitory effect on BCGF enhancement of B cell proliferation. The F(ab')2fragment of AB5 generated by pepsin digestion was similarly inhibitory as was the intact Ig. ABS‐mediated inhibition was independent of the target B cell state of activation. Both resting and activated B cells (anti‐μ or staphylococcal protein A activated) incubated with similar concentrations of AB5 were unresponsive to BCGF. The abilitv of anti‐CR2 antibodies to block BCGF‐dependent B cell proliferation suggests that occupancy of C3d membrane receptors may result in modulation of B cell proliferation in physiolo

ISSN:0014-2980    

DOI:10.1002/eji.1830160406

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractThe functional effects of anti‐Ig antibodies have been investigated, using an experimental system where B cell activation is brought about by direct and specific interactions with T helper (Th) cells without participation of surface Ig releptors on the responding B cell. We have used Thcell lines and clones directed to class II major histocompatibility complex antigens of the responding B cells, and titrated into cooperative cultures either purified rabbit anti‐mouse μ, or monoclonal mouse anti‐δ antibodies. Both types of antibodies greatly enhanced B lymphocyte responses to suboptimal concentrations of functionally efficient Thcells, while they had no effect in cultures containing optimal Th: B cell ratios. In contrast, helper activity by low efficiency Thwas, at all Th: B cell ratios, enhanced by appropriate concentrations of anti‐Ig antibodies. Anti‐Ig effects were exclusively observed when B cells were the targets for “cognate” recognition by Thcells. We conclude that ligand binding to surface Ig receptors on resting B cells fails, in our experimental conditions, to overcome “linked” collaboration, but it greatly facilitates productive Th−B cell interactions. Whatever the mechanisms underlying this facilitation, the observations imply roles of surface Ig in Th−dependent B lymphocyte activation other than either passive “focusing” of antigen or activation into reactivity to

ISSN:0014-2980    

DOI:10.1002/eji.1830160407

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractMouse splenic macrophages (MΦ) were tested for their ability to potentiatein vitroallogeneic mixed lymphocyte response (MLR) of highly purified syngeneic responder T cells against allogeneic MΦ. It was shown that even extremely low numbers of MΦ, syngeneic to the responder T cells were able to induce significantly stronger MLR. This potentiating effect was demonstrated to be expressed via the self‐Ia antigens present on the surface of syngeneic MΦ., The functional involvement of self‐Ia antigens was substantiated by two approaches: (a) by using monoclonal antibodies specific for I‐region determinants of the responder haplotype MΦ, and (b) by setting up MLR cultures with stimulator MΦ of (responder X stimulator) F1origin which express both self‐ and allo‐Ia antigens. The results obtained in this study demonstrate that the presentation of self‐Ia antigens, in conjunction with the recognition of allomajor histocompatibility complex antigens, are required forin

ISSN:0014-2980    

DOI:10.1002/eji.1830160408

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractDNA methylation at the 5′‐CCGG‐3′ sites of the HLA‐DRα gene and relative flanking regions has been analyzed by Msp I and Hpa II enzymatic digestion in order to determine whether a correlation exists between DNA methylation and transcription of the HLA‐DRα gene.Unexpectedly, and in contrast to the behavior of most eukaryotic genes, no positive correlation was found between hypomethylation and expression. In fact, HLA‐DRα appears to be fully unmethylated at Msp I/Hpa II sites in K562 cells, not expressing DR molecules, and to exhibit a high degree of methylation in Colo 38 cells, which actively transcribe the gene.The unorthodox behavior of HLA‐DRα is not unique to melanoma or erythroid cells since a similar, positive correlation between methylation and expression also exists when this analysis is extended to cell lines belonging

ISSN:0014-2980    

DOI:10.1002/eji.1830160409

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractLymphocyte proliferation in response to monocytes pulsed with an antigenic extract ofCandida albicanswas measuredin vitroand the effects of modifying major histocompatibility complex (MHC) class II antigen expression at the surface of the antigen‐presenting cells was investigated. The study shows that no simple correlation exists between changes in MHC class II antigen expression and changes in the effectiveness of antigen presentation. Recombinant interferon‐αl(rIFN‐αl), rIFN‐γ and hydrocortisone were found to increase the expression of monocyte class II MHC antigens. In contrast, rIFN‐α2did not increase class II antigen expression although it did increase MHC class I expression. Treatment of monocytes with rIFN‐αl, rIFN‐α2or corticosteroids during antigen pulsing resulted in a reduction in the subsequent proliferative lymphocyte response. In all cases this inhibitory effect was restricted to antigen‐specific proliferative responses since the polyclonal lymphocyte response to pokeweed mitogen‐pulsed monocytes remained unaffected. Only rIFN‐γ treatment of antigen‐pulsed monocytes resulted in enhancement of the subsequent specific lymphocyte proliferative response. The suppressive effects of hydrocortisone could not be attributed to its well documented inhibitory effects on arachidonic acid metabolism. The effect ofC. albicansantigen, IFN and corticosteroids on interleukin 1 (IL1) production by monocytes was also investigated.C. albicansantigen alone induced IL 1 production. So too did IFN‐αland IFN‐γ IFN‐α2did not induce IL 1 production. Addition of interferons together withC. albicans, however, resulted in the same level of IL1 productions as withC. albicansantigen alone. Neither antigen nor IFN had any effect on IL1 action in the thymocyte assay.Corticosteroids did not affect IL 1 production by monocytes but were potent antagonists of IL 1 in the thymocyte proliferation assay. Mitogen‐induced thymocyte proliferation was also inhibited by corticosteroids. Pretreatment of monocytes with hydrocortisone followed by washing did not markedly affect their subsequent ability to produce IL 1 neither was it possible to reverse the inhibitory effects of hydrocortisone on antigen presentation by addition of exogenous IL1. Thus, signals which alter class II MHC antigen expression influence the antigen‐presenting capacity of monocytes by a mechanism independent of IL 1. No simple correlation exists between class II e

ISSN:0014-2980    

DOI:10.1002/eji.1830160410

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractEffects of carrageenan (CAR) treatment on the response of interferon (IFN) productionin vivoandin vitroafter stimulation with an IFN‐γ inducer, staphylococcal enterotoxin A (SEA), was investigated. The IFN‐γ production in mice stimulated with SEA was impaired after i.v. administration of a 20 mg/kg dose of CAR. Spleen cells (SC) from CAR‐treated mice had decreased ability to produce IFNin vitroafter stimulation with the same inducer. SC obtained from mice during the suppressive state inhibited IFN‐γ production when they were co‐cultured with mononuclear cells prepared from spleens of untreated control mice. This suppressor cell activity could be removed from SC by an adherence technique to plastic surface. The SC with suppressor activity were not inactivated by treatments with monoclonal anti‐Thy‐1.2 antibody, anti‐asialo GM1 antisera and anti‐mouse immunoglobulin antisera followed by complement. The suppressive activity was detected in cell‐free culture fluids of macrophage fractions containing suppressor cell activity. These results suggest that the decrease in IFN‐γ production in mice pretreated with CAR may associate with the presence of suppressor cells characterized to the mo

ISSN:0014-2980    

DOI:10.1002/eji.1830160411

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY