摘要:

AbstractN4‐Dinitrophenyl‐L‐2,4‐diaminobutyric acid hydrazide was coupled to aldehyde groups generated by periodate oxidation of sialyl residues on thymocytes. Anti‐2,4‐dinitrophenyl(Dnp)antibody was found to stimulate mature, hydrocortisone‐resistant thymocytes, while it had no mitogenic effect on the immature thymocytes.In order to study the involvement of different regions of the antibody molecule in the triggering process of stimulation, the mitogenicity of various antibody fragments was also assessed. The divalent F(ab')2was found to be a superior mitogen compared to the intact antibody when added to Dnp‐conjugated thymocytes. The monovalent Fab' and Fab fragments have no mitogenic activity indicating that cross‐linkage may be a prerequisit

ISSN:0014-2980    

DOI:10.1002/eji.1830080502

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractLymphocytes from normal, young adult rats were autosensitizedin vitroagainst trypsin‐dissociated autologous testis cells. The autoimmune response had been assayed both by determination of the lymphocyte proliferation, using a [3H]thymidine incorporation test, as well as by determination of their specific cytostatic activity against monolayer‐forming testis cells which was measured in a terminal51Cr uptake assay. The actively responding cells in this system are T lymphocytes. Non‐T cells can exert additional, nonspecific cytostasis. The immune specificity of thein vitroexperimental autoimmune orchitis (EAO) has been demonstrated on two levels. First, the responding T lymphocytes were found to specifically adhere around cells from one particular test is subpopulation which morphologically resemble Sertoli cells. The rosetting lymphocytes respond only to testicular self antigen, but not to allogeneic lymphocytes. Second, specificity to the effector T lymphocytes was revealed in transfer experiments. Autosensitized EAO effector T cells cytostatically affected only major histocompatibility gene complex (MHC)‐compatible testis cells. Their reactivity against MHC‐different testis cells or MHC‐compatible nontesticular fibroblasts was significantly decreased which suggests both tissue as well as MHC specificity of the E

ISSN:0014-2980    

DOI:10.1002/eji.1830080503

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractWe have investigated the impact of a range of cytochalasins of various classes, not only on T cell‐mediated cytolysis as a whole, but also at each stage of this process using the analytical Ca++pulse method. We compared the results thus obtained with the effect of some of these drugs on microfilaments (assessed by electron microscopy) and on glucose metabolism. All cytochalasins blocked the recognition stage of T cell‐mediated cytolysis, none blocked the target cell disintegration stage, and all cytochalasins but cytochalasin A blocked Ca++‐dependent events of the lethal hit stage. Cytochalasin A, which did not block lethal hit, clearly affected microfilaments. Cytochalasin B blocked both the lethal hit and glucose catabolism while cytochalasin A inhibited neither. The following pattern is therefore suggested. The recognition stage can be blocked by both cytochalasin A and cytochalasin B, presumably through a common effect of these drugs on microfilamental structures. The lethal hit stage can be blocked by cytochalasin B but not by cytochalasin A, presumably through the impact of the former on cell membrane permeability to glucose. These results are discussed both in terms of their practical interest relative to the use of Ca++and cytochalasin A to probe lytic events, and in terms of the information they provide about metabolic steps and cell structures which could be involved in the letha

ISSN:0014-2980    

DOI:10.1002/eji.1830080504

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractThe experiments described here were designed to test the validity of the allosteric immunoglobulin model of Huber et al. (Nature1976.264: 415) according to which antigen could cause a stiffening of the flexible antibody molecule by the formation of longitudinal CH1–CH2interdomain contacts. The largest structural change would involve the folding of the hinge peptide in‐between the CH2globules. Consequently, the accessibility of the hinge region to reduction and limited proteolysis should be considerably altered.Homogeneous rabbit antibodies to type II and III pneumococcal polysaccharide were reacted with corresponding oligosaccharide haptens and whole polysaccharide antigens to form monomeric and polymeric IgG antibody complexes, respectively. Reduction of the inter‐heavy chain disulfide bond in the hinge region by a series of thiol reagents of increasing size and polarity was performed; the ratio of reduction rate in complexes with hapten or antigen compared to that of hapten‐or antigen‐free control was found to be close to unity, thus indicating that the susceptibility of the hinge disulfide bond was unaffected by the binding of hapten or antigen. Limited proteolysis in the hinge region of immune complexes by activator‐free papain or pepsin in the absence of reducing agent was carried out, and the appearance of antibody fragments followed by sodium dodecyl sulfate gel electrophoresis. The rate of proteolysis in hapten‐antibody complexes and in large soluble antigen‐antibody aggregates (16–29 S) did not show any significant decrease when compared to that for unliganded antibody.The identity of the reduction and proteolysis rates in the presence and absence of antigen provides strong evidence for the lack of a major conformational change in the hinge region upo

ISSN:0014-2980    

DOI:10.1002/eji.1830080505

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractAllelic exclusion of thekpolypeptide chain allotypes b4 and b5 of the rabbit exists for the immunoglobulins of almost all plasma cells and of most mature small B lymphocytes. However, both these alleles are expressed simultaneously in rare plasma cells and in an usually large fraction of the lymphoid cells of the bone marrow. Our experiments support the idea that such bone marrow B lineage cells do not always show allelic exclusion.

ISSN:0014-2980    

DOI:10.1002/eji.1830080506

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractThe ontogeny of IgD was examined in neonatal to adult mice by immunofluorescence. The first δ‐positive cells appeared in the spleen at about 3 days of age, while lymph nodes from 4 to 5‐day‐old mice already contained 10–20% δ‐positive B cells.In order to study the function of IgD, we developed a system in which the appearance of δ‐positive cells was suppressed by treatment of mice from birth with an anti‐δ allotype serum. Immunofluorescence studies showed that very few δ‐positive cells could be found in the spleen and lymph nodes of such suppressed mice, and also that the percentage of μ‐positive cells was reduced by about 50%. The recovery from suppression was rapid, indicating that potential δ‐positive cells were modulated rather than killed. Studies of the immune response of suppressed micein vitroandin vivoshowed that suppression had little effect on the IgM response but caused a definite red

ISSN:0014-2980    

DOI:10.1002/eji.1830080507

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractRat spleen cells are shown to be unresponsive to sheep red cells (SRBC)in vitrounder conditions in which thoracic duct lymphocytes (TDL) respond very well. By adding unresponsive spleen cells to responsive TDL cultures, the spleen cells are shown to contain an inhibitor capable of preventing the response to SRBC. The inhibitory activity is a property of live cells; it is sensitive to radiation doses as low as 100 R × rays and to mitomycin C. It can be completely removed from spleen cell suspensions by extraction with large amounts of carbonyl iron or by filtration through nylon wool columns. It is less efficiently removed by filtration through Sephadex G‐10 columns, and is completely resistant to the cytotoxic effects of silica. From a practical point of view, extraction of a spleen cell suspension with carbonyl iron is a useful method of obtaining fully responsive lymphocyte populations from rat sple

ISSN:0014-2980    

DOI:10.1002/eji.1830080508

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractThe two mitogens, lipopolysaccharide (LPS) and lipoprotein (LP), both stimulate to an equal extent murine B lymphocytes to develop IgG‐synthesizing and IgG‐secreting cells. IgG synthesis and secretion was detected either by biosynthetic labeling of stimulated B cells, followed by immunoprecipitation and polyacrylamide gel electrophoresis of labeled Ig, or by the protein A plaque assay detecting all IgG‐secreting cells with IgG‐specific developing antisera. B cells from spleen, lymph node, thoracic duct and fetal liver of normal and T cell‐deficient nu/nu mice are all stimulated by the two mitogens to develop IgG‐secreting cells. Mitogen‐induced IgG secretion, therefore, can occur independently of T cells and of external antigen.Anti‐Ig antibodies inhibit the mitogen‐induced development of Ig‐secreting cells. Antibodies with specificities for μ chains when added before or soon after mitogenic stimulation of small, resting B cells, will inhibit these cells from developing into IgG‐secreting cells. Later in culture, antibodies with specificities for γ chains also become inhibitory for the mitogen‐induced development of IgG‐secreting cells. These results indicate that the precursors of the IgG‐secreting cells carry IgM in the outer surface membrane. They also suggest that during mitogen‐stimulated growth of B cell clones, IgG becomes expressed in the surface membrane in a functional way which allows the inhibition of mitogen‐induced I

ISSN:0014-2980    

DOI:10.1002/eji.1830080509

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractThe activation of T lymphocytes from poly (Glu60Ala30Tyr10)n(GAT)‐primed donors by GAT‐pulsed nonimmune spleen cells was shown to require identity at the I‐A subregion of the major histocompatibility complex. However, GAT‐primed T lymphocytes from (responder × nonresponder) F1hybrids could only be stimulated to proliferate by GAT bound to high responder or F1spleen cells but not by GAT bound to spleen cells from the low responder parent. The failure of spleen cells from low responder parental strains to present GAT was shown not to be due to the presence of suppressor cells in either the antigen‐presenting or the responding cell populations. These results indicate that control of antigen‐presenting cell‐T lymphocyte interactions is one site of Ir g

ISSN:0014-2980    

DOI:10.1002/eji.1830080510

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY

摘要:

AbstractAdults of two urodele amphibian species (Triturus cristatus carnifexandCynops hongkongensis) and two anuran species (Rana temporariaandXenopus laevis laevis) were immunized with a 25 % suspension of sheep or horse erythrocytes.After eight or 14 days, splenic lymphocytes were removed, and their specific red cell‐binding capacities tested by immunocytoadherence. Antigen‐binding cells were classified as high‐dose nonsecretory (S−) or secretory (S+), according to whether they bound a single layer or several layers of erythrocytes.The stimulation of both α and β adrenoreceptors reduced the numbers of S+rosettes formed byTriturusandCynopslymphocytes, whereas a β agonist increased and an α agonist decreased S+rosette formation byRanaandXenopussplenic lymphocytes. These effects were blocked by α and β adrenoreceptor antagonists.Low‐dose immunization ofXenopuswith a 0.0025% suspension of sheep erythrocytes gave a minimal number of S+rosettes two and eight days after immunization, and β adrenoreceptor stimulation had no effect on antigen binding.These results are discussed in terms of the distribution of α and β adrenoreceptors in amphibians and possible relationships between S+and high‐dose S−antigen‐binding cells, and support the view that functional lymphocyte heterogeneity exists in

ISSN:0014-2980    

DOI:10.1002/eji.1830080511

出版商:WILEY‐VCH Verlag GmbH    

年代:1978

数据来源: WILEY