摘要:

AbstractH‐2‐lacking murine embryonal carcinoma (EC) cells have been proposed as universal targets for natural killer (NK) effectors from different species because their killing appeared to be uncomplicated by potential T cell effector mechanisms (Stern, P. L. et al.,Int. J. Cancer1981.27: 679). While some previous studies had shown that murine cytotoxic T cells were unable to lyse EC cells, rat T killers are shown here to be active against these targets and to be distinguishable from NK cells.Percoll density fractionation of rat peripheral blood lymphocytes enriches in parallel for NK‐mediated lysis of both EC or YAC target cells. These NK cells, unlike T cells, do not mediate lectin‐dependent and cell‐mediated cytotoxicity (LDCC) of NK‐insen‐ sitive target cells. This procedure is thought to reveal the total cytolytic potential of stimulated T cell populations, regardless of specificity. In contrast to previous results with mice, we found that allogeneically primed rat cytotoxic T cells can kill murine EC cells in LDCC and, further, that rat cytotoxic T cells, generated by stimulation with mouse spleen cellsin vitro, can lyse murine EC cells directly.This demonstration of T cell lysis of EC cells suggests that either there is a novel mechanism of lysis operating without requirement for major histocompatibility com‐ plex (MHC) structures, or EC cells express some hitherto unidentified MHC‐like structures on t

ISSN:0014-2980    

DOI:10.1002/eji.1830150112

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractSeveral strains of mice, most notably the SJL strain, have a greatly reduced level of circulating λl immunoglobulins (rλ110phenotype) compared with other mice. The locus responsible for this phenotype has been shown to be closely linked to the structural Cλl gene. Functionally this locus has been said to reduce the number of lymphocytes expressing surface λl molecules. In order to gain a better understanding of this phenomenon we compared the functional properties of activated B cells secreting λl immunoglobulins in the splenocytes of both BALB/c and SJL mice.Our results indicate that regulatory T cells, as well as regulatory ontogenetic processes, are not responsible for the rλ1lophenotype. In addition, limiting dilution analyses revealed that the number of lipopolysaccharide‐sensitive precursors of λl‐secreting B cells was similar in the splenocytes of the two strains of mice tested. The quantity of λl molecules produced by a B cell clone, however, was found to be lower in SJL than in BALB/c mice. As the level of λl mRNA is greatly reduced in lipopoly‐saccharide blasts of SJL mice, as compared to the mRNA detected in BALB/c blasts, we conclude that the impairment responsible for the rλ110phenotype is probably transcriptional. We tentatively propose that sequences 5′ to the Cλl region are defective in their capacity to enhance the λl tran

ISSN:0014-2980    

DOI:10.1002/eji.1830150113

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractThe C3d receptor is a specific marker of B lymphocytes. Recently we have shown that C3d receptor activity is carried by a gp140 membrane antigen. A polyclonal antibody has been prepared by immunizing a rabbit with highly purified gp140 molecule isolated from membranes of the human B lymphoblastoid cell line Raji and its high specificity was previously demonstrated. We tested the effect of this antibody to the C3d receptor on the B cell proliferative response. Purified B cells from human blood were induced to proliferate by a B cell growth factor (BCGF)‐containing partially purified supernatant from activated T cells. The anti‐C3d receptor F(ab′)2enhanced the BCGF‐dependent B cell proliferation. This effect was dose dependent, was observed in the presence of different concentrations of BCGF and did not correspond to a change in the time course of the response. The anti‐C3d receptor F(ab′)2had no mitogenic effect in the absence of T cell supernatant. In contrast the undigested anti‐C3d receptor IgG suppressed the BCGF‐dependent B cell proliferation. These results emphasize the potentialities of anti‐gpl40 F(ab′)2to explore the involvement of the C3d receptor in the regulation of B cell response

ISSN:0014-2980    

DOI:10.1002/eji.1830150114

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractThe activities of 8 S and 6 S DNA ligases have been studied in the chicken lymphoid cells of blood, spleen and bursa of Fabricius at different stages of development, from late embryonic life to about 3 months after hatching. These cells have been sorted with the fluorescence‐activated cell sorter FACS Il on the basis of size and T or B antigenicity (immunofluorescence). The light 6S DNA ligase has been previously demonstrated to be associated to a late stage of differentiation of thymocytes. In the bursa, a unique form of 8 S DNA ligase is found during the whole period of observation. This form of enzyme remains in the B cells of the spleen until 3 weeks after hatching, but is never present in the blood B cells. As far as T cells are concerned, the light DNA ligase is present in the blood from 18‐day embryonic life on. In the spleen T cells, on the contrary, this enzyme appears only 3 weeks after hatching. Before this stage, splenic T cells are devoid of any form of DNA ligase activity. These findings show biochemical differences in T and B lymphocytes colonizing the periphery, blood and spleen, and suggest, at least for the T cells at early stages, a heterogeneity in the degree of differentiat

ISSN:0014-2980    

DOI:10.1002/eji.1830150115

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractTo discover whether individual bursal follicles can contain clones of B lymphocytes, we estimated the numbers of lymphoid cell precursors populating single follicles in two types of chicken chimera. The first type was produced by establishing parabiotic connections between blood vessels of embryo chorioallantoic membranes. Under these conditions, and most likely during normal development, most follicles are populated by more than one, but less than ten, precursor cells. However, in a second type of chimera, a cyclophosphamide‐treated chick reconstituted with normal bursal cells, most follicles in the reconstituted bursa are clonal (their lymphocytes are derived from a single precursor cell). Individual follicles can readily be isolated from bursae of reconstituted birds and should be useful in studies of B cell developmen

ISSN:0014-2980    

DOI:10.1002/eji.1830150116

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractT3 is a human differentiation antigen expressed exclusively on mature T cells. In this study it is shown that anti‐T3 monoclonal antibodies, in addition to their capacity to induce T cells to proliferate, are able to induce antigen‐specific cytotoxic T lymphocyte clones to mediate antigen nonspecific cytotoxic activity. It is furthermore shown that anti‐T3 reagents are able to trigger lytic activity in T cell clones characterized as noncytotoxic antigen‐specific proliferating T cells. The data presented indicate that perturbation of T3 can trigger the lytic machinery in cytolytic as well as noncytolytic T cell

ISSN:0014-2980    

DOI:10.1002/eji.1830150117

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractTo investigate whether small B cells can stimulate mixed lymphocyte reactions (MLR), highly purified populations of large vs. small B cell fractions were tested for their capacity to evoke MLR across Mls vs. H‐2 barriers. Large B cell fractions stimulated high MLR to Mls and H‐2 determinants, irrespective of whether the stimulators were exposed to irradiation or pretreated with mitomycin C. In accord with the findings of others, irradiated small B cell fractions proved to be very poor stimulators of MLR. Significantly, however, mitomycin C‐treated small B cell fractions elicited high MLR, particularly to Mls determinants.The finding that small B cell fractions treated with irradiation are poor stimulators of T cells correlates with the known radiosensitivity of B cells. In this respect, the widely held view that small B cells do not have antigen‐presenting cell (APC) function rests largely on studies with irradiated B cells. The present finding that T cells respond well to small B cells treated with mitomycin C, however, indicates that small B cell fractions do have APC function. Whether the APC function of small B cells reflects a response to resting B cells per se rather than to cells undergoing activationin vitro, however, remains to be asce

ISSN:0014-2980    

DOI:10.1002/eji.1830150118

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractIgG‐binding factors (IgG‐BF) prepared from cell‐free supernatant of human peripheral blood mononuclear cells interfere with the polyclonal activation of peripheral B cells by decreasing the numbers of IgG‐containing cells and Ig plaque‐ forming cells. UsingNocardia opacadelipidated cell mitogen (NDCM), a T helper cell‐independent polyclonal B cell activator, it was found that the suppressive effect of IgG‐BF was no longer demonstrable after removal of T cells. In pokeweed mitogen‐stimulated cultures, the suppression by IgG‐BF required the presence of radiosensitive T cells. Selective depletion of OKT4+or OKT8+subsets in NDCM‐stimulated cultures showed that IgG‐BF required the presence of OKT4+lymphocytes to induce suppression. It is concluded that the effect of human IgG‐BF was mediated by one or sev

ISSN:0014-2980    

DOI:10.1002/eji.1830150119

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractPlasma samples from male CBA, BALB/c and DBA/2 mice were subjected to poly‐acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Bands of C6 hemolytic activity in the washed resolving gel were identified by means of an erythro‐cyte/agarose overlay gel. CBA plasma was found to contain two forms of C6, one with a molecular weight (M,) of approximately 90 000 (type A) and one with a M, of 100000 (type B); CBA mice were thus designated C6 : A+B+. BALBk and DBAR plasma on the other hand contained only the low molecular weight type A C6 and were designated C6: A+B−. Flat bed isoelectric focusing followed by functional overlays showed that CBA plasma produced two sets of hemolytic bands (PI 5.25–5.4 and 5.0–5.2) whereas BALB/c and DBA/2 plasma produced only the more cathodal band set. The additional band set in CBA plasma corresponded to the high‐Mrtype B C6. Results of breeding experiments demonstrated that the possession of the high Mrtype B C6 was inherited in the manner of an autosomal phenotypically dominant cha

ISSN:0014-2980    

DOI:10.1002/eji.1830150120

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractHybrids formed by fusion of either human acute lymphoblastic or chronic lymphocy‐tic leukemia cells and the mouse myeloma P3.X63.Ag81653 have been used to show that the expression of two cell surface antigens, Bp37 and p76, associated with B cell activation and detected by the monoclonal antibodies BB1 and BB2, respectively, segregate with human chromosomes 12 and 19, respectively. Another antigen expressed on activated B cells (p24) also maps to chromosome 12 (Katz et al.,Eur. J. Immunol.1984.13:1008) which is of interest in the light of the frequent involvement of this chromosome in certain B cell leukemias and lymphoma

ISSN:0014-2980    

DOI:10.1002/eji.1830150121

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY