摘要:

AbstractAnti‐HLA alloantisera inhibit mixed lymphocyte responses in which normal lymphocytes are used as stimulator cells. These same antisera are unable to inhibit lymphocyte proliferative responses stimulated by lymphoblastoid cells from cultured lymphoid cell lines. They also fail to inhibit either the generation of cytotoxic effector cells by lymphoblastoid cells or lymphocyte‐mediated cytotoxicity against the lymphoblasts. Although the number of HLA antigens on the surface of lymphoblasts is reported to be greater than on normal lymphocytes, the failure of alloantisera to inhibit lymphoblast‐induced responsesin vitrodoes not appear to be due to insufficient amounts of antiserum to react with the antigenic sites. Rather, the data are interpreted to suggest that antigens which are not HLA and are not closely associated with HLA on the lymphocyte membrane are responsible for the stimulation of allogeneic lymphocytes by lymphoblastoid cells.Although lymphoid cell lines are known to contain the genome of the Epstein‐Barr virus, antisera against products of the viral genome fail to inhibit proliferative responses to lymphoblastoid cells, suggesting that these antigens do not directly participate in lymphocyte act

ISSN:0014-2980    

DOI:10.1002/eji.1830060402

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractSelective breeding has been performed in mice for their high or low antibody responsiveness to Salmonella antigens (Ag). Two noncross‐reacting Salmonellae (S. typhimurium and S. oranienburg) have been alternately used to immunize successive generations in order to avoid interference of maternally transmitted antibody. Both Salmonellae carry two independent antigens: flagellar (f) and somatic (s). Two two‐way selections were carried out: one for agglutinin response to fAg and the other for agglutinin response to sAg (Selection Ags). The agglutinin response to the other independent Ag was also measured (Associated Ags). The phenotypic character chosen for selection is the maximal agglutinin titer in response to optimal immunization.In both selections, high and low responder lines diverged progressively. There was a 27‐fold interline difference in the F13generation of selection for fAg response and a 38‐fold one in the F11generation of selection for sAg response. This divergence and the continuous distribution of phenotypes in the foundation population indicate that the quantitative character investigated is subject to polygenic regulation. The realized heritability (h2) of the character, measured from the interline divergence, was 0.18 ± 0.06 in both f and s selections. This means that about 20 % of the phenotypic variance of the foundation population is additive.The modification of immune responsiveness to the selection Ag produced by selective breeding was accompanied by a parallel and equivalent effect on immune responsiveness to the noncross‐reacting Associated Ag. This effect is therefore entirely nonspecific. A small but definite sex effect in favor of female antibody responsiveness was demonstrated.The results are discussed in comparison with other selection experiments made in mice for quantitative antibody response to othe

ISSN:0014-2980    

DOI:10.1002/eji.1830060403

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractDirect visualization of the events resulting from LPS stimulation of mouse spleen cellsin vitrowas achieved by characterizing the cells during four days of culture for morphology, Ig and Θ surface markers and autoradiography after [3H] thymidine uptake. The changes observed were related to biochemical parameters such as incorporation of [3H] thymidine into DNA, Ig biosynthesis and secretion.Two pathways of B lymphocyte differentiation were observed: a) the generation of a large number of small B lymphocytes with high density of surface Ig but no internal pool detectable by immunofluorescence, and b) the maturation of a very small proportion of cells with a large intracellular pool and the ability to secrete Ig. Both cell types arise from dividing blast cells, either physically separated or traced by pulse chase experiments with [3H] thymidine.We discuss whether this duality is caused by the triggering of different B cell subpopulations at different developmental stages, preprogramed to one or the other pathway or whether the final direction of development depends on the microenvironment of individual dividing cells

ISSN:0014-2980    

DOI:10.1002/eji.1830060404

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractAfter treatment with papain (6 mg/ml) for 1 h, P815 tumor cells became resistant to complement‐mediated lysis by mouse alloantibodies of different specificities. Immunofluorescence and absorption studies indicated that this resistance was associated with removel of the corresponding antigenic determinants from the cell surface. In contrast, papain‐treated tumor cells were fully susceptible to lysis by rabbit antiserum against P815 cells, indicating a) no alteration of the membrane sensitivity to complement damage, and b) a dissociation between structure and/or localization of allo‐ and xenoantigens.Papain‐treated cells were also completely resistant to lysis by cytolytic T lymphocytes (CTL) during the first 60 min after completion of the enzyme treatment. Susceptibility to lysis by either CTL or alloantibody and complement reappeared within a few hours after incubation in culture medium and was virtually normal by 6 h. Treatment of P815 cells with trypsin (2 mg/ml) had no effect on either humoral or cellular lytic act

ISSN:0014-2980    

DOI:10.1002/eji.1830060405

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractEvidence for the genetic determination of A100 allotypic specificity suggests that it is the product of an allele at thealocus. The A100 allotypic specificity was detected in a wild rabbit lacking all the known specificities of the a series. None of the 8 rabbits possessing the A100 allotypic specificity possessed two allotypic specificities of the a series. The concentration of A100+molecules is larger in the serum of a presumably homozygous rabbit than in that of a presumably heterozygous rabbit. In the sera of heterozygous A100+rabbits, the A100 allotypic specificity and the known specificity of the a series are carried by different molecules. The determinants responsible for the A100 allotypic specificity are present both on IgG and IgM. They are located on the heavy chain and the Fab fragment of IgG. A family of variants of A100 specificity has been detected and cross‐reactivity between A100, a1 and a3 specificities has been found. This was detected and studied with anti‐a3 antisera. It seems that A100 allotypic specificity is closer to a3 specificity than a1 is to a3 specific

ISSN:0014-2980    

DOI:10.1002/eji.1830060406

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effect ofin vitrotreatment of mouse lymph node cell populations with lipopolysaccharide (LPS) on their migration in syngeneic recipients was studied.LPS‐exposed cells had a decreased lymph node localization and an increased spleen distribution when compared to control untreated cells, after intravenous injection into syngeneic recipients. This effect of LPS on cell traffic was maximal at 24 h and could not be detected at either 1 or 72 h after cell transfer.These changes induced on cell distribution by LPS treatment are interpreted as the consequence of a modified interaction between the circulating lymphocytes and the resident cells within the spleen of the recipient

ISSN:0014-2980    

DOI:10.1002/eji.1830060407

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe modifications of the thymocyte membrane which are induced by concanavalin A (Con A) were studied by means of the variation of electro phoretic mobility which the lectin induces on the cell. The electrophoretic mobility of thymocytes is increased when Con A is used under conditions expected to induce a cap formation and the subsequent endocytosis. This increase persists as long as the lectin is present in the medium and disappears as soon as the lectin is eliminated. The redistribution of the Con A receptors into spots and caps may partially explain this electrical modification. The ionized groups of the thymocyte membrane are drastically modified during these phenomena with: 1) a diminution by 61% in the density of the sialic carboxyl groups, 2) a decrease of 40% in the density of phosphate groups and of 60% in the density of amino groups, 3) a 20 times higher density of unidentified negatively charged groups.The electrophoretic mobility of normal human blood lymphocytes is similarly increased by Con A. A marginal difference exists in the shape of the dose response curves obtained when normal and cancerous thymocytes react with increasing doses of Con A. No measurable electrical modification was observed during redistribution of H‐2 and Thy‐1.2 antigens on EL4 cells.Some experiments suggest a possible correlation between the mitogenicity of the lectin and a measurable modification of the cell electrophoretic mobil

ISSN:0014-2980    

DOI:10.1002/eji.1830060408

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractTransfer of thymus cells from young chickens in combination with a light whole body irradiation (360 R) was found to suppress the rejection of skin grafts across strong histocompatibility (B) differences. On the average, the suppressed animals also showed decreased serum hemagglutinin titers against erythrocytes of the skin donor strain and a decreased graft‐versus‐host (GvH) reactivity against embryos of this strain.The thymic suppressor cells can be obtained from animals that have not experienced the antigen under test. However, after transfer and contact to the antigen (skin graft) they can lead to the formation of specific (“activated”) suppressor cells and can mediate in the long run a specific inhibition of the response to this antigen.The suppressive activity is associated with a bursa‐dependent cellular subpopulation in the thymus that is different from B lymphocytes, B precursor cells or GvH‐reactive T cells. The bursa dependency of the thymic suppressor cell suggests that functionally different lineages of thymic and thymus‐derived lymphocytes are derived from different sources of prethymic stem cells. The suppressor cells are predominantly found in the young chicken thymus and already detectable in the 16‐day‐old embryo, while poor suppressive activity is found in the adult thymus.The suppressive effect can be obtained with thymus cells from either syngeneic or allogeneic donors. Embryonic allogeneic donors provide suppressive cell preparations free of GvH reactivity.The possibility that the thymus suppressor cells mediate self tolerance and “neonatal tole

ISSN:0014-2980    

DOI:10.1002/eji.1830060409

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractSpleen cells from unimmunized mice were exposed to two contrastingly fluorescent antigens simultaneously. Antigen‐binding cells of either specificity were isolated using a fluorescence‐activated cell sorter (FACS). Purified cells binding one or the other of the antigens were then examined by fluorescence microscopy for the presence of bound antigen of the alternate specificity.No double binding cells were seen. If cells bear receptors of two or more specificities and these receptors are randomly distributed among antigen‐binding cells, then of the 13 000 binding cells examined 82 were expected to bind both antigens. These results strongly suggest that antigen‐binding cells bear receptors of only one specificity. In addition, by inference from the functional correlation between antigen‐binding cells and precursor cells, the data support the contention that precursors of antibody‐forming cells are m

ISSN:0014-2980    

DOI:10.1002/eji.1830060410

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY

摘要:

AbstractThe defects in two nonsecreting variant clones of the mouse plasmacytoma MOPC 21 (P3) were studied by tissue culture methods. The variants (NSI and NSIII) do not synthesize detectable heavy chains. NSI synthesizes, but does not secrete, light chains and NSIII does not synthesize light chain.A screening procedure was used allowing the detection of revertant cells secreting immunoglobulin. The method is based on a hemolytic plaque assay using anti‐immunoglobulin‐coated red cells. No revertants were detected among 2 × 107cells. Both variant lines were fused to another myeloma line (PI) which secretes a complete immunoglobulin and excess light chains. Analysis of the products by isoelectric focusing showed that in the hybrids there was no reactivation of synthesis of the nonexpressed chains. The defects leading to loss of synthesis cannot therefore be complemented in the hybrid lines.The secretion of light chain in NSI, on the other hand, could be complemented in the hybrid but the light chain was only secreted as part of a new immunoglobulin hybrid mole

ISSN:0014-2980    

DOI:10.1002/eji.1830060411

出版商:WILEY‐VCH Verlag GmbH    

年代:1976

数据来源: WILEY