摘要:

AbstractThe immunological reactivity against the N‐terminal region of hen egg‐white lysozyme (HEL) has been investigated by a synthetic peptide (PHEL) comprising residue 1–18 of HEL and by an analogue peptide (PREL) in which phenylalanine at position 3 is substituted by tyrosine. Both peptides are immunogenic in (C57BL/10 × DBA/2)F1mice genetically responder to HEL. In C57BL/6 mice, genetically nonresponder to HEL, PRELinduces anti‐peptide antibodies that also bind to PHELwhereas PHELis not immunogenic.Thus, a single amino acid substitution in a synthetic peptide converts a nonresponder mouse strain into a responder one. Anti‐PHELantibodies demonstrate a higher binding to HEL than anti‐PRELantibodies, indicating that phenylalanine at position 3 is important for induction of anti‐peptide antibodies able to recognize native HEL. At the T cell level the two peptides show very high bidirectional cross‐reactivity between themselves and with HEL for interleukin 2 production, antigen‐specific proliferation and delayed‐type hypersensitivity response, whereas conservation of phenylalanine at position 3 is required for induction of suppressor cells cross‐reactive with HEL. This indicates that the N‐terminal region of HEL contains epitope(s) able to induce the same level of helper T cell activity as the native HEL molecule. However, helper T cells do not discriminate between PHELand PRELwhereas phenylalanine at position 3 is critical for HEL‐specific s

ISSN:0014-2980    

DOI:10.1002/eji.1830160102

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractHereditary deficiency of the third component of complement, C3, is found very seldom in the human. C3 deficiency is associated with severe bacterial infections revealing the central role of C3 in complement activation via the classical or alternative pathway. We describe a new hereditary C3 deficiency in strain 2 guinea pigs. Serum from these animals had a markedly reduced lytic activity in a standard assay for complement‐dependent, antibody‐mediated cytotoxicity. In functional assays of individual components, the hemolytic activity of the components C4, C2, C5 and of factors B, D and H was in the normal range. The functional C3 titer, and similarly C3 antigenic activity in the serum of these C3‐deficient animals (C3D) was on average only 5.7% of normal activity. Typing the animals with alloantisera or monoclonal antibodies to guinea pig Ia‐antigens revealed that the C3D animals had the major histocompatibility complex‐haplotype of inbred strain 2 guinea pigs (B.1, Ia. 2,4). The C3 defect is not linked to the major histocompatibility complex and, in addition, is not linked to a C3a receptor deficiency. Macrophages and hepatocytes of the C3D animals have an unimpaired capacity for synthesis and secretion of C3 as measured by enzyme‐linked immunosorbent assay. There was no indication for hypercatabolism of normal C3 by the animals as shown by plasma clearance of125I‐radiolabeled C3. Thrombocytes of the C3D animals responded normally to stimulation with purified C3a in an ATP‐release assay without an indication for a desensitizationin vivo.Possibly the fault resides in an enhanced susceptibility of their own C3 to proteolysis. However, C3 partially purified from the plasma of the C3D animals or secreted by hepatocytes exhibited no obvious structural differences to purified normal C3 in sodium dodecyl sulfate‐polyacrylamide gel electrophoresis or in immunoblotting. The C3D serum had a reduced bactericidal activity compared to normal or to C4‐deficient serum. Nevertheless, the animals are apparently healthy without an indication for increased frequency of bacterial infections. These guinea pigs provide an unique model for analysis of the biological functions of C3in vivoandin vitrowithout the need for artificial C3‐depletion procedures with all their known and

ISSN:0014-2980    

DOI:10.1002/eji.1830160103

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractWe report here defined culture conditions that allow reproducibly the growth of the majority of immature thymocytes from both fetal (14–15 days of gestation) and adult mice. The combination of phorbol myristate acetate (PMA), ionomycin and recombinant interleukin 2 (IL2) is both sufficient and necessary to induce growth of about 1/6.2 (range 1/3–1/9) and 1/4.3 (range 1/2–1/7) immature thymocytes from adult and fetal mice, respectively, in serum‐free cultures. Several other combinations tested (e.g.PMA + IL2, concanavalin A + IL2) were poorly or not active. None of the agents tested alone (PMA, ionomycin, concanavalin A, pokeweed mitogen, IL2) had any effect. We found no evidence for a role of IL1 and IL3 on growth of these cells. The growth of activated immature thymocytes from either fetal or adult mice was inhibited by a monoclonal antibody against mouse IL2 receptors.Under the same conditions that stimulated growth of most immature thymocytes, they did not mature into cells expressing Lyt‐2, L3T4 or T cell antigen receptor (KJ16) after 7 to 15 days of continuous proliferation in culture. Nor did they give rise to cells with cytolytic activity after 7–9 days of culture. In some but not all experiments cultures of immature thymocytes from adult mice but not from fetal mice generated cells (1 out of 120–310) with helper function for B lymphocytes.While we confirmed here that ∼50–70% freshly isolated immature thymocytes express receptors for IL2, our results indicate that these cells need to be activated (bye.g.PMA + ionomycin) to respond to IL2. A possible mechanism to account for the expression of nonfunctionally competent IL 2 receptors is proposed and our results concerning the maturation of immature thymocytesin v

ISSN:0014-2980    

DOI:10.1002/eji.1830160104

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractMonoclonal antibodies reactive with distinct T lymphocyte subpopulations have been described in man, mouse and rat and structural analyses of these antigens have demonstrated a high degree of evolutionary conservation. This report describes the reactivity of three monoclonal antibodies (mAb), 19–19, αSBU‐T4 and αSBU‐T8, which define T cell subpopulations in the sheep. The mAb αSBU‐T4 and αSBU‐T8 define the sheep CD4 and CD8 molecules, respectively. These two antigens show similar tissue distributions, molecular weights and fluorescence‐activated cell sorter profiles to human, mouse and rat CD4 and CD8 molecules. The mAb 19–19 is reactive with a subpopulation of T lymphocytes which displays a tissue distribution unlike that reported for a T cell subset in any other species. 19–19 stains 7% of efferent lymph lymphocytes, 15% of peripheral blood lymphocytes but only 1–3% of lymph node lymphocytes. Two‐color immunofluorescence demonstrates that the 19–19+T cell subset is SBU‐T4−and SBU‐T8−, and thus defines a third T cell subpopulation in sheep. Immunohistology on frozen lymph node tissue sections localizes 19–19 mAb‐reactive cells to the subcapsular region of the lymph node and lymph node trabeculae. Only 1% of thymocytes are 19–19+and these cells are located mainly in the medulla and often arranged as foci around blood vessels. The 19–19 mAb immunoprecipitates from sheep lymphocytes an antigen with an apparent molecular mass of 215 kDa under both reducing and nonreducing conditions. It is concluded that αSBU‐T4 and αSBU‐T8 recognize the sheep homologues of the human T4 and T8 antigens, respectively, whereas 19–19 recognizes an antigen (termed SBU‐T1

ISSN:0014-2980    

DOI:10.1002/eji.1830160105

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractFcγ receptor‐bearing U937 cells, when incubated in serum‐free buffer, were found to release spontaneously a suppressor material for pokeweed mitogen‐drigen IgG synthesis which could be retained on Sepharose 4B‐IgG immunosorbents. Immunosorbents coupled with IgM or F(ab′)2fragments of IgG were unable to retain the inhibitory activity of U937‐derived material, suggesting a binding specificity for the Fcγ fragment of IgG. This suppressor material corresponds therefore by definition to an IgG‐binding factor (IgG‐BF). The mechanism forin vitrosuppression of the antibody response by U937‐derived IgG‐BF was investigated. It did not interfere with cell proliferation and displayed maximum effect when added at day 3 of the culture period. Tested for its effect on IgG, IgM and IgA synthesis, IgG‐BF suppressed antibody production following a pattern specific for IgG. Finally gel filtration of the suppressor material gave rise to two peaks of inhibitory activity with an apparent molecular mass comprised between 30 to 40 kDa and 60

ISSN:0014-2980    

DOI:10.1002/eji.1830160106

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractThe effect of high antigen dose on the activation of cytochromecpeptide‐primed lymph node cells was determined in several strains of mice by a limiting dilution analysis. It was found that proliferation of cytochromecpeptide‐specific T cells was completely inhibited at high antigen concentration in C57BL/6 but only partially in DBA mice and had no effect in SJL mice. Clones derived from DBA mice showed a differential capacity to be inhibited by high antigen dose. On the other hand, interleukin 2 moduction by these clones was not impaired regardless of the antigen concentrations u

ISSN:0014-2980    

DOI:10.1002/eji.1830160107

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractThein vitroproliferation of human peripheral lymphocytes induced by interleukin 2 (IL 2), a product of cDNA, cloned inE. colihas been studied. The maximal mitogenic signal is given by concentrations ≦2.5 U/ml. Due to growth factor consumption, at least 10 U/ml are needed to maintain a logarithmic response until day 6. The anti‐Tac antibody, directed against the IL2 receptor, effectively blocks this response, but we could not obtain a decrease of IL2‐reactive cells by depletion of putativein vivoactivated Tac+cells, using this antibody and a fluorescence‐activated cell sorter.Depletion of Leu 7+and Leu 11b+cells does not cause a decrease of the response, which indicates that the responding cells are not confined to the natural killer lineage. By simultaneous staining of cell‐surface markers and DNA, the nature of the proliferating cell was determined. More than 90% of the dividing cells expressed HLA class II and the Tac antigen, whereas the lymphocyte populations, defined by the surface markers Leu 2, Leu 3, Leu 4, Leu 7 and Leu 11b, were all represented in the dividing cells. The magnitude of the response was proportional to the number of monocytes present in the culture. Depletion of monocytes completely abrogated the response, whereas an increase in the number of monocytes to a 1:1 ratio with lymphocytes caused a 2‐fold increase in proliferation. However, purified T cells do proliferate to IL 2 when cultured in the presence of a supernatant that was harvested from a 2‐day culture of adherent monocytes. The proliferation‐inducing activity in the supernatant eluted with apparent molecular weights of 15 000 and 75 000 on an Ultrogel AcA‐54 column. Therefore, we conclude thatin vitro, in the presence of an IL 1‐like activity produced by monocytes, IL2 is mitogenic for a po

ISSN:0014-2980    

DOI:10.1002/eji.1830160108

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractConditions are described for the induction of autoimmunity to Thy‐1 and a large panel of monoclonal CBA and AKR autoantibodies has been characterized. These reveal a hitherto unrecognized complexity at the Thy‐1 locus and evidence for intragenic control. Epitopes recognized by the autoantibodies differed in species and tissue distribution from alloantigenic determinants but their specificity was confirmed by transfection studies with the cloned Thy‐1bgene. The quantitative and qualitative differences in epitope expression between Thy‐1aand Thy‐1balleles were inherited as single Mendelian traits and in the absence of recombinants, suggesting translationa

ISSN:0014-2980    

DOI:10.1002/eji.1830160109

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractThe antigenic structure of the diphtheria toxin has been studied in man. B and T cell responses to diphtheria toxoid and to different fragments of the toxin molecule were analyzed in 4 individuals one month after booster immunization. Studies on the B cell response showed that: (a) part of the response was directed against assembled topographic sites; (b) 80% of the response was directed against determinants present on fragment A; (c) the few determinants present on the CNBr peptides of B cross‐react with determinants present on A; and (d) reduction of the second disulfide bridge of fragment B diminishes the response. In contrast to the antibody response, most of the T cell reactivity was directed against the B fragment or CNBr peptides from this fragment. Analysis of the fine specificity of T lymphocyte clones revealed that some CNBr fragments share common T cell determinants. These studies indicate that T and B cell determinants are differently distributed on the molecule and that large cross‐reactivities that are not explained by the analysis of the amino acid sequence could be found at the B and T cell le

ISSN:0014-2980    

DOI:10.1002/eji.1830160110

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY

摘要:

AbstractThe predominance ofxover λ light chain expression in mice can either reflect the probability of rearrangement of the relevant locus or be the result of antigen‐driven clonal expansion. To discriminate between these two possibilities we determined, by limiting dilution analysis, the frequencies ofx‐ and λ‐producing cells in B lymphocytes generatedin vitrofrom bone marrow pre‐B cells. The frequencies obtained in these cultures are not significantly different from those obtained with mature spleen cells. In addition, Southern blot analysis of bone marrow‐derived and splenic cell DNA revealed that in both populations the extent of B lymphocytes having undergone λ1 gene rearrangement does not exceed 4%. These results, therefore, establish that in the mouse the low level of λ light chain expression directly reflects the probability of rearrangement of the r

ISSN:0014-2980    

DOI:10.1002/eji.1830160111

出版商:WILEY‐VCH Verlag GmbH    

年代:1986

数据来源: WILEY