摘要:

AbstractTwo cloned murine helper T lymphocyte (HTL) lines were used to investigate the immunoregulatory properties of highly purified interleukin 2 (IL2). The clone, designated J6.19, secretes lymphokines, including IL2, and proliferates when stimulated with ovalbumin in the presence of I‐Ak‐bearing spleen cells, while the alloreactive clone, L2, secretes lymphokines, including IL2, and proliferates when stimulated with Mlsa,d‐bearing spleen cells. When either clone was exposed to a high concentration of pure IL2 for 1 to 2 days in the absence of either antigen or spleen cells, the HTL became unresponsive to rechallenge with antigen. Unresponsiveness to antigen was indicated by an inability of HTL to proliferate or secrete usual amounts of IL 2 or colony‐stimulating factor. Within 5–7 days after exposure to IL2, the cloned HTL again responded to antigen. Thus, in addition to being a growth factor for HTL, IL2 can limit the magnitude of the HTL response to antigen. L2 or J6.19 cells could also be induced to secrete lymphokines by the lectin, concanavalin A (Con A) or by a combination of the calcium ionophore, A23187, and phorbol myristate acetate (PMA). After exposure of L2 or J6.19 cells to sufficient IL2 to induce unresponsiveness to antigen, cells were also unresponsive to Con A, as indicated by a reduction in the level of lymphokines secreted. In contrast, lymphokine levels stimulated by A23187/PMA were comparable to those produced by cells not exposed to IL2. The failure of antigen to stimulate lymphokine release and proliferation by HTL previously exposed to IL2 therefore may result from an inability of HTL to recognize antigen or to transduce effectively the antigen recognition signal. Several T cell surface molecules are known to be involved in antigen activation of HTL; these include the antigen receptor and the “associative recognition” structures L3T4 and LFA‐1. We observed that L2 cells, rendered unresponsive to antigen by exposure to IL2, expressed normal levels of antigen receptor, as identified by the monoclonal antibody, KJ16–133.18. Furthermore, expression of L3T4 and LFA‐1 was not decreased. Unresponsiveness to antigen induced by IL2 thus could not be correlated with decreases in the expression of antigen receptors, L3T4, or LFA‐1. Unresponsive HTL may therefore be capable of recognizing antigen but the signal generated by antigen binding may be attenuated during its transduction, resulting in the failure of cloned HTL to proliferate or secrete lymphokine

ISSN:0014-2980    

DOI:10.1002/eji.1830160302

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractHuman dimeric IgA was injected i.v. into chickens whose bile was then collected. The human IgA which had been transported across the hepatocytes of the chicken was subsequently purified from the bile and shown to be associated with a protein of 80 kDa and pI 4.6, which reacted with rabbit antisera to chicken bile proteins but not with an antiserum to human α chain. The chicken bile protein thus has functional and biochemical properties similar to those of mammalian secretory component

ISSN:0014-2980    

DOI:10.1002/eji.1830160303

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractA comprehensive synthetic approach, for the localization of the full profile of the continuous antigenic sites on proteins, previously introduced by this laboratory, was applied here to localize the continuous antigenic sites of ragweed allergen, Ra3. The following 10 consecutive peptides, each comprising 15 residues (except for peptide 91–101) and overlapping each of its neighbors by 5 residues, were synthesized and purified: 1–15, 11–25, 21–35, 31–45, 41–55, 51–65, 61–75, 71–85, 81–95 and 91–101. Quantitative radiometric titrations of protein and peptide adsorbents were performed with125I‐labeled anti‐Ra3 IgG antibodies from rabbit, outbred mouse and human antisera. The specificity of antibody binding to peptide adsorbents was confirmed by inhibition experiments. These studies established the full profile of antigenic (IgG‐binding) sites of Ra3 and permitted comparison with the allergenic (IgE‐binding) sites recently localized. It was found that the recognition by IgG antibodies was independent of the host species in which the antibodies were raised. Furthermore, the regions recognized by human IgE antibodies coincided with those recognized by IgG antibodies in three different species. Thus, Ra3 was found to have 4 continuous antigenic sites which occupy the same loca

ISSN:0014-2980    

DOI:10.1002/eji.1830160304

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractIn the preceding report, we described the systematic localization of the full profile of the continuous antigenic sites on ragweed allergen, Ra3, with antibodies from three different host species using a comprehensive strategy, previously introduced by this laboratory. The strategy consists of studying the immunochemical activity of a series of consecutive synthetic overlapping peptides, of uniform size and overlaps, which encompass the entire protein chain. This study reports the localization of the continuous regions on Ra3 that are recognized by T cells from mice immunized with Ra3. The 10 overlapping peptides encompassing the entire Ra3 molecule were examinedin vitrofor their ability to stimulate lymph node cells from Ra3‐primed BALB/c (H‐2d), C3H/He (H‐2k) SWR (H‐2q) and SJL (H‐2s) mice. Several regions of the molecule (T sites) were found to stimulate Ra3‐primed lymph node cells. This strategy has enabled the localization of the full submolecular profile of T cell recognition of the Ra3 molecule by these mouse strains. Three of the regions recognized by T cells coincided with regions recognized by antibodies (i.e.B cells). It is noteworthy that in addition to sites recognized by both T and B cells the protein has at least one site which is recognized exclusively by T cells and to which no detectable antibody response

ISSN:0014-2980    

DOI:10.1002/eji.1830160305

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractA new monoclonal antibody (mAb), named 3.9, is described that is specific for the p150,95 molecule, a member of the LFA‐1, CR3, p150,95 family of human leukocyte differentiation antigens. The LFA‐1 molecule participates in a variety of T cell interactions and the CR3 molecule is the receptor for the complement component iC3b, but little is known about the p150,95 molecule. Here we show that the expression of p150,95 is confined to myeloid cells. mAb 3.9 reacts variably with neutrophils, more strongly with monocytes and is most strongly expressed on tissue macrophages. Using this mAb and others, we have examined the heterogeneity of tissue macrophages. Cells such as Langerhans' cells, dendritic reticulum cells and osteoclasts failed to react with these mAb and thus, probably do not belong to the mononuclear phagocyte lineage. Using a new double‐labeling technique, we investigated lymphoid tissue for dendritic cells bearing class II molecules which might function in interactions with T cells. In T cell areas macrophages expressing class II markers were seen but there was no evidence for other types of dendritic or interdigitating cells which expressed class II molecules but not macrophage epitopes. The conclusion from this survey was that the most prominent cell with dendritic morphology found in the T cell areas of lymphoid tissue was a macro

ISSN:0014-2980    

DOI:10.1002/eji.1830160306

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractIn this report we have analyzed cell cycle‐related fluctuations of both quantity and density of the T cell differentiation antigens, CD3 (T3), CD4 (T4) and CD8 (T8), as well as the major histocompatibility complex (MHC) antigens on the cell surface of activated T cells. Phytohemagglutinin‐activated T cells cultured for 3 days with or without conditioned medium or for 10 days with conditioned medium and mixed lymphocyte culture‐derived T cell clones were used for the analysis. Correlated measurements of the surface antigen quantity (immunofluorescence), DNA content (dye Hoechst 33342), and cell size (light scatter), not influenced by synchrony induction methods and cell fixation, were performed by dual‐beam flow cytometry. Our results demonstrate that the T cell differentiation antigens, CD3, CD4 and CD8, and class I MHC antigens are increased in density in the G1phase for all activated T cells tested. In contrast, class II MHC antigens are increased in density in the G2phase of activated T cells maintained with conditioned medium. Since it is known that the T cell differentiation antigens and class I MHC antigens on activated T cells are necessary for proliferation of T cells, our study suggests that this effect is more significant in the G1phase. The cell cycle changes in expression of class I and class II MHC antigens, but not of the T cell differentiation antigens, appear to be mediated by soluble factors, probably including interferon‐γ, which could produce a differential increase of class I and class II MHC antigens on G2p

ISSN:0014-2980    

DOI:10.1002/eji.1830160307

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractSpecific antibody responses to influenza virus were obtainedin vitrofrom human blood mononuclear cells (PBMC). Antibody production in these cultures was profoundly suppressed by the addition of allogeneic T cells with the surface phenotype Leu2a+(CD8+), Leu8−. Suppression by allogeneic T suppressor (Ts) cells required interactions only between T‐depleted B (E−) cells and allogeneic Leu2a+. No evidence was obtained for T‐T cell interactions, or for Tsinducer cells similar to those described for nonspecific antibody responses to pokeweed mitogen. Moreover, allogeneic E+, or allogeneic Leu2a+cells were able to suppress specific antibody responses by E−cells when help was provided by T cell‐replacing factor showing that the target of suppression was the responding E−cells, and not T helper cells. In contrast to allogeneic T cells, allogeneic E−cells did not suppress antibody production when added to cultures of unfractionated PBMC (E−+ E+). That is, Tscells activated to allogeneic E−were unable to suppress antibody production by the syngeneic E−cells present in the same culture tube. This result shows that alloactivated Tscells were specific for the allogeneic E−target cells, and that suppression was not mediated by nonspecific allogeneic effects. Allogeneic Tscells therefore differ from Tscells in pokeweed mitogen responses by their specificity, and by their activation in the abs

ISSN:0014-2980    

DOI:10.1002/eji.1830160308

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractDeoxyguanosine (dGuo) inhibits thymic blast DNA synthesis and then induces thymocyte cell death. The dGuo inhibitory action, measured with four different assays (spontaneous thymidine incorporation, immunofluorescent detection of 5‐bromodeoxyuridine incorporation, dye exclusion, tetrazolium salt cleavage), was suppressed in the presence of supernatants from cultures containing phagocytic cells. In particular, we studied the anti‐dGuo activity in supernatants from thymic reticulum cultures (TRS) and in those from phagocytic cells isolated from TR cultures (P‐TR). The anti‐dGuo substance was identified as deoxycytidine (dCyd) by high performance liquid chromatography and other physicochemical studies. Secretion of dCyd by P‐TR is accompanied by thymidine but not by purine nucleoside secretion. A dual mechanism of thymocyte rescue by dCyd was demonstrated by a study of the dose‐dependencies of dCyd‐mediated prevention and reversal, respectively, of the dGuo inhibition. In addition to this exogenously added anti‐dGuo action, dCyd and dCyd‐containing TRS induced significant stimulation of spontaneous thymic blast proliferation, and the kinetics of both effects were identical.These findings might suggest that a major role of thymic phagocytic cells is the supply of pyrimidine nucleosides to thymocytes resulting in the maintenance of proliferation and protection of at least some thymic blasts from the toxic effects of dGTP accumulation. The role of this system in the intrathymic selection pro

ISSN:0014-2980    

DOI:10.1002/eji.1830160309

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractThe murine monoclonal antibody F23.1 reacts with an allotypic determinant on the β chain of the T cell receptor expressed by approximately 20% of T helper and cytotoxic T lymphocytes of most common mouse strains. This IgG2aantibody, either in soluble form or covalently coupled to Sepharose beads, can activate resting T cells from naive animals to proliferate. Interestingly, under all conditions of activation, the antibody can only induce proliferation if exogenous lymphokines in the form of Con A supernatant are provided. Thus, it is unlike most lectins and anti‐T3 antibodies in this regard. Furthermore, under all conditions of culture, F23.1 activates preferentially the Lyt‐2+subset of T cells. This is the case even in the presence of accessory cells. Further evidence is provided that two soluble lymphokines, different from IL2, are required to initiate IL2‐dependent growth and to allow the expression of lytic ac

ISSN:0014-2980    

DOI:10.1002/eji.1830160310

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractMice were i.v. immunized with various 2,4,6‐trinitrophenyl (TNP)‐carrier conjugates, and the development and localization of specific (i.e.anti‐TNP) antibody‐forming cells (AFC) in the spleen was studied. The nature of the carrier used, thymus dependent (TD) or thymus independent type 1 or type 2 (TI‐1, TI‐2), had marked effects on the number and time of appearance of AFC. However, no influence of the different carriers on the localization of specific AFC in the spleen was observed. By using a double immunocytochemical technique we could simultaneously determine specificity (anti‐TNP) and isotype (class and subclass) of the AFC. The TNP‐carrier conjugates evoked (intracellular) immunoglobulins with carrier‐characteristic isotype distribution. No carrier‐dependent localization pattern, in the lymphoid compartments of the spleen, of these AFC was found. These results show for the first time the actualin situeffects of various TI and TD carriers on the development of specific AFC. Based on the present findings, no direct evidence for a special role of the marginal zone in the immune response against TI‐2 antigens could be demonstrated. We suggest that this new method forin vivoinvestigation, in combination with existing standard enzyme‐ and immunohistochemical techniques, can provide more insight into the precise role of lymphoid and nonlymphoid cells in TD

ISSN:0014-2980    

DOI:10.1002/eji.1830160311

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY