摘要:

AbstractEpstein‐Barr virus‐transformed human B cells (EBV‐B cells), but not resting B cells or B cells activated by T cell‐derived factors, have been shown to support the proliferation of tetanus toxoid (TT)‐specific autologous T cell clones in response to TT antigen. The accessory cell function of EBV‐B cells was compared to that of monocytes with regard to antigen uptake and processing.After an 18‐h incubation period with125I‐labeled TT, the amount of radioactivity associated with the cells (∼ 50 ng/107cells) and the percentage of cells containing radiolabeled material (∼ 50%) were equivalent for EBV‐B cells and monocytes. Like with monocytes, EBV‐B cells pulsed with TT for 18 h or more were equivalent in their capacity to induce T cell proliferation to EBV‐B cells to which soluble TT was added for the duration of the culture period.The requirements for antigen uptake and presentation to T cells were similar for both EBV‐B cells and monocytes. Both processes were energy dependent, inhibited by cold (4 °C), 2‐deoxyglucose, and azide, and both required node novoprotein synthesis as they were not affected by pretreatment of the cells with the irreversible protein inhibitor pactamycin. Trypsin treatment of antigen‐pulsed EBV‐B cells and monocytes followed by fixation for 1 min in 0.03% paraformaldehyde completely abolished the capacity of both cell types to induce T cell proliferation.In both EBV‐B cells and monocytes, antigen presentation, but not antigen uptake, was inhibited by the addition of the lysosomotropic agent chloroquine during the antigen‐pulse period suggesting that the mechanisms of antigen processing are similar for both cell types. Vacuoles positive for acid phosphatase with an electron microscopic structure similar to that of lysosomes were found in EBV‐B cells but not in resting B cells or B cells activated by T cell‐derived factors.The present observations indicate that EBV‐B cells take up antigen and process it in a fashion similar to monocytes. The presence of lysosomes appears to correlate wit

ISSN:0014-2980    

DOI:10.1002/eji.1830140403

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractThe specificity of four cytotoxic T lymphocyte (CTL) clones which recognize class II major histocompatibility complex (MHC) antigens was analyzed. All clones recognized antigens associated with the serologically defined HLA‐DRw6 specificity. The activity of two of these clones, JR‐2‐2 and JR‐2‐10, could be inhibited by a monoclonal antibody Q 5/13 specific for a monomorphic determinant present on HLA‐DR. In contrast, the activity of the two other CTL clones, JR‐2‐19 and JR‐2‐26, was not blocked by Q 5/13, but by a new monoclonal reagent, SPV‐L3. This latter monoclonal antibody precipitated a two‐chain structure of 28 kDa and 33 kDa and reacts with a monomorphic determinant. The molecular weight of the polypeptides precipitated with SPV‐L3 was slightly less than those precipitated with a HLA‐DR‐specific monoclonal reagent. In addition two‐dimensional gel electrophoresis showed that the antigen precipitated by SPV‐L3 differed in charge from those precipitated with the anti‐HLA‐DR antibody. These results indicate that SPV‐L3 recognizes a class II MHC product different from HLA‐DR. This observation was confirmed by partial amino acid sequence analysis of the two chains which revealed that the molecule precipitated by SPV‐L3 is homologous to HLA‐DC/DS molecules. Therefore this report provides the first evidence that human cytot

ISSN:0014-2980    

DOI:10.1002/eji.1830140404

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractA monoclonal antibody, termed 3‐2F1, is specific for the rabbit VHa1 allotypic marker. This antibody appears to recognize a common a1 determinant since it reacts with all of the a1 immunoglobulin (Ig) that is bound by polyclonal rabbit anti‐a1, and completely inhibits the binding of polyclonal anti‐a1 to a1 Ig. When tested for the predominant IdX‐a1 idiotype previously shown to be expressed on virtually all rabbit anti‐a1 antibody, it was found that 3‐2F1 also bears this idiotype. In fact, sequential absorption and inhibition assays indicate that 3‐2F1 displays the entire set of rabbit IdX‐a1 determinants. The results are consistent with the concept that the anti‐IdX reagent bears a latent internal image of the co

ISSN:0014-2980    

DOI:10.1002/eji.1830140405

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractTreatment with a monoclonal anti‐Thy‐1 antibody and complement completely prevented C57BL spleen cells from causing graft‐vs.‐host disease following their inoculation into newborn CBA mice. The proportion of mice that became tolerant to C57BL antigens, as measured by skin grafting, was significantly less compared with mice given (CBA × C57BL)F1hybrid cells. This was not due to the elimination of T cells, for antibody‐treated F1cells induced tolerance as readily as complement‐treated control F1cells.To investigate whether the apparent superiority of F1cells over C57BL cells is attributable to differences in the mechanism inducing and maintaining unresponsiveness, two approaches were followed. First, the level of donor cell chimerism in the spleens of tolerant animals was studied. Though no difference between F1and C57BL cells was uncovered, the presence of T cells in the donor inocula favored the establishment of chimerism. Second, the involvement of suppressor T cells was examined in adoptive transfer experiments. Splenic suppressor T cells were associated with tolerance regardless of how it was elicited. Preliminary results with F1cells show that the tolerogenic property is not confined to any one cell type. It is proposed that the greater tolerogenicity of F1cells is brought about by the presence of host‐type (self) antigens, which enable the tolerogenic signals to operate without recourse to antigen processing

ISSN:0014-2980    

DOI:10.1002/eji.1830140406

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractThe effect of cyclosporin A (CsA) on the delayed‐type hypersensitivity (DTH) elicited in mice by sheep red blood cells was investigated. Evidence is presented that a single injection of CsA adversely affects the inflammatory reaction. Sensitized T lymphocytes initiate the DTH reaction by their recruiting activity on phagocytic cells which infiltrate the cutaneous site of antigen deposition. CsA administration has no adverse effect on the recruitment of phagocytic cells at the site of the inflammatory reaction. The present studies show that CsA acts on specific T cells: (a) in adoptive transfer, T‐DTH‐mediating cells cannot elicit a response in mice treated with CsA 8 h before; (b) when collected 8 h after a single injection of CsA, T‐DTH‐mediating lymphocytes are no longer able to adoptively transfer the reaction. This conclusion is strengthened byin vitrostudies: (a) the frequency of T‐DTH‐mediating lymphocytes is 50‐fold decreased after a shortin vitroincubation with CsA; (b)in vitroproduction by concanavalin A‐activated lymphocytes of chemotactic pro‐inflammatory mediator(s) is abolished

ISSN:0014-2980    

DOI:10.1002/eji.1830140407

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractWhole anti‐I region antisera and monoclonal anti‐Ia antibodies are capable of totally inhibiting the response of murine spleen cells to the non‐H‐2 Mls alloantigens. This inhibition was shown to be highly specific for the appropriate Ia and operative at the level of the stimulator cell. Both cell proliferation and interleukin (IL 2) production were inhibited; however, the inhibition of cell proliferation was not due only to the inhibition of IL 2 production and the inhibition of IL 2 production was not solely due to the inhibition of IL1 production. We propose that both the IL 2‐producing cell and the proliferating cell need to “see” an intact Ia+cell and perhaps Ia antigens in association with Mls determinan

ISSN:0014-2980    

DOI:10.1002/eji.1830140408

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractThe OKT3 monoclonal antibody has unique reactivity for human T cells and induces a mitogenic response equal to that of concanavalin A (Con A). However, significant differences were found in activation requirements for the two T cell mitogens. Although both OKT3 and Con A required living accessory cells for stimulation of T cells, the OKT3 antibody was optimally mitogenic at a molar concentration 103times less than Con A. Under such conditions, the two mitogens showed similar kinetics as well as magnitude or responses. Furthermore normal IgG blocked the OKT3‐induced proliferation selectively. The inhibition is most likely caused by the Fc portion of IgG competing for Fc receptors on accessory cells. The different requirements for activation are discussed in relation to the T cell receptor and its role in T cell activatio

ISSN:0014-2980    

DOI:10.1002/eji.1830140409

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractSingle‐ and dual‐parameter fluorescence‐activated cell sorter analyses of complement receptor‐positive and ‐negative (CR+and CR−) splenic B cells of normal andxidimmunodeficient mice were performed to determine the frequencies of surface (s) IgM+and sIgD+cells, as well as the quantities of sIgM and sIgD on these cells. Single parameter analysis revealed identical frequencies of sIgM+and sIgD+cells in the CR+B cell population of normal mice. In contrast, the percentage of sIgM+cells exceeded that of sIgD+cells in the CR−normal and CR+xidB cell population to a similar extent. CR−xidB cells showed an even greater discrepancy between sIgM+and sIgD+cells.Dual‐parameter analysis of CR+normal B cells showed the typical sIg phenotype of mature B cells,i.e.an intermediate density of sIgM and a high density of sIgD. The CR+xidB cell population displayed an increase in cells with high sIgM and no‐to‐low sIgD and a decrease in cells with intermediate sIgM and high sIgD when compared to CR+normal cells. CR−B cells from normal andxidimmunodeficient mice were similar in that both consisted largely of a cell population with low sIgM and no‐to‐low sIgD. However, the CR−normal B cell population also contained cells with intermediate sIgM and high sIgD, which were lacking in the CR−xidcell population. Similar results were obtained when CR+and CR−B cells from normal andxidmice were purified from a small resting B cell population, isolated by elutriation. This indicates that the sIg phenotype of CR−cells is not due to the presence of large cells whi

ISSN:0014-2980    

DOI:10.1002/eji.1830140410

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractA proportion of cloned T cells derived from allogeneic mixed leukocyte cultures (MLC) was found to stimulate rapid primary, but not secondary, lymphoproliferative responses of autologous as well as allogeneic peripheral blood mononuclear cells (PBMC). Of eight major histocompatibility complex (MHC) class II‐specific monoclonal antibodies (mAb), the reagent TÜ39 (which preferentially inhibits allostimulation by SB‐ rather than DR‐ or DC‐associated determinants) most strongly inhibited stimulation by these clones. MAb specific for DC or DR molecules inhibited weakly or not at all. Stimulatory, but not nonstimulatory, clones were found to be strongly suppressive when titrated directly into MLC. Suppression was not MHC restricted, was radioresistant (20 Gy) and was not abrogated by the addition of partially purified interleukin 2 to the test cultures. Transfer of PBMC cocultured with stimulatory, but not with nonstimulatory, clones into a second MLC resulted in its strong suppression, suggesting that a suppressor effector population had been “induced” by the clones. These results are consistent with the hypothesis that SB‐like, rather than DR or DC, determinants present on the surface of certain activated T cells are intimately involved in the regulation of cellular immune responses by rapidly inducing suppressor effector cells in normal lymphocy

ISSN:0014-2980    

DOI:10.1002/eji.1830140411

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY

摘要:

AbstractThe transferrin receptor (TfR) was recently proposed as putative natural killer (NK) cell target structure. Here data are presented against this hypothesis and it is shown that low TfR expression and high NK sensitivity can occur concommitantly. K562 cells were studied at various stages of cell proliferation. No change in NK sensitivity could be observed between exponential growth and the plateau phase, whereas TfR expression completely disappeared during the latter. Protein synthesis inhibitors such as cycloheximide (1 μg/ml, 48 h) and actinomycin D (50 μg/ml, 48 h), that abolished the TfR expression at the K562 cell surface, had no effect on NK sensitivity. Similarly, hemin induction (0.1 mM, 5 days) did not change NK susceptibility of K562 cells but considerably diminished TfR expression. Moreover, attempts to block NK sensitivity with anti‐TfR monoclonal antibodies were unsuccessful, even when the 42.6 antibody, which is known to bind to the active site of TfR, was used. Finally, no blocking of NK sensitivity could be achieved when K562 cells were preincubated with saturating concentrations of transferrin or when transferrin was added during the NK assay. It therefore seems doubtful that TfR is the unique target structure for NK cells. It remains possible that TfR and NK target structures are often coexpressed on actively dividing ce

ISSN:0014-2980    

DOI:10.1002/eji.1830140412

出版商:WILEY‐VCH Verlag GmbH    

年代:1984

数据来源: WILEY