摘要:

AbstractAnin vitrosplenic focus assay for B cell cloning was used to analyze the responses of primary and secondary B cells obtained after fractionation on (1 × g) velocity sedimentation gradients. When nonimmune adult bone marrow cells are fractionated, the small cell (slowly sedimenting) fraction contains the majority of primary B cells specific for the 2,4‐dinitrophenyl determinant (DNP). When nonimmune adult spleen cells are fractionated, all of the cell fractions contain B cells specific for DNP or for fluorescein (FL), and the large and medium cell fractions contain approximately 50 % of the activity. There is a differential expression of IgMvs.IgG1anti‐hapten monoclonal antibody, in that the majority of primary splenic B cells which give rise to clones producing only IgM antibody are found predominantly in the large and medium cell fractions. All of the cell fractions contain B cells which can generate clones producing both IgM and IgG1, or only IgG1antibody. Ia‐“negative” B cells which give rise to clones producing only IgM antibody are found in the large and medium cell fractions, whereas all the cell fractions contain la‐positive B cells. When secondary spleen cells are fractionated, all of the cell fractions contain secondary B cell activity. The large and medium cell fractions contain half of the DNP‐specific secondary B cells, whereas the medium and small cell fractions contain more secondary B cells specific for FL or hemocyanin. The large and medium cell fractions of secondary spleen cells are not enriched for B cells giving rise to clones producing onl

ISSN:0014-2980    

DOI:10.1002/eji.1830070602

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractA previous study of primary and secondary immune responses of rats and mice immunized against various protein antigens allowed us to describe a population of immunocytes containing, synthesizing and secreting immunoglobulins without detectable antibody function against the antigen injected (IFC). We here report their T cell‐dependence. Mice, thymectomized, irradiated and reconstituted with bone marrow or fetal liver cells, generally show neither antibody‐forming cells (AFC) nor cells synthesizing immunoglobulin without detectable antibody function. In some mice, probably only partly T cell‐deprived, antibody‐containing cells were seen, and at that time they were associated with cells synthesizing immunoglobulin without detectable antibody function. For most of the animals studied in primary response, however, the IFC population remained higher than the AFC population throughout the immune response. In normal animals immunoglobulin‐synthesizing cells were predominant at the beginning of the immune response, then decreased and progressively replaced by antibody‐synthesizing cells. After the first injection or after two stimuli, the number of responders among T cell‐deprived mice increased progressively. Finally, these experiments indicate that both cells synthesizing immunoglobulins without detectable antibody function and specific AFC are thymus‐dependent and rule out the hypothesis according to which horseradish peroxidase is a polyclonal B

ISSN:0014-2980    

DOI:10.1002/eji.1830070603

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractThe responses to a wide dose‐range of ovalbumin (OV) have been comparatively studied in terms of IgE and hemagglutinating antibodies in high line (HL), low line (LL) and interline cross mice.The kinetics of the primary and secondary responses, which differ according to the antigen dose injected, are parallel in each line, for both types of antibody with the exception of a greater susceptibility of IgE to suppression after higher doses.The threshold doses of antigen which are quite different in HL, LL and F1mice are, in each case, similar for both IgE and hemagglutinating antibody induction. Furthermore, in primary response, the dominance effect in F1is of “low responsiveness” for 0.05 μg OV and of “high responsiveness” for 0.5 μg OV. The inversion of dominance occurs at the same OV dose for IgE and hemagglutinating antibodies. This is also true for minor doses in secondary response. When individual responsiveness to a minute dose of OV is investigated in interline F2and backcross mice, a high correlation coefficient is observed between IgE and hemagglutinating antibodies.Finally, the frequency distribution curves of responsiveness to a minute dose of OV (0.05 μg)in HL, LL, F1, F2and backcross mice are compatible with the hypothesis of a one locus regulation for both IgE and hemagglutinating antibo

ISSN:0014-2980    

DOI:10.1002/eji.1830070604

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractMercuric chloride induces anti‐glomerular basement membrane antibodies in the Brown‐Norway rat. Various other inbred rat strains (Lewis, Wistar AG, August, PVG/c) were not found t o be able to produce such antibodies under the same experimental conditions. Hybrids (F1, F2and F1× LEW) were bred from Brown‐Noway and Lewis rats and injected with mercuric chloride. It has been demonstrated that the induction of anti‐glomerular basement membrane antibodies by mercuric chloride in these crosses is under genetic control. The response was found t o depend on two or three genes one of which was H‐1‐linked. The negative results obtained with L.BN congenic rats were in complete agreement with thi

ISSN:0014-2980    

DOI:10.1002/eji.1830070605

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractAllospecific mouse T cells derived from one‐way mixed lymphocyte cultures after 19 months in tissue culture still require allogeneic stimulation for their proliferation. If injected into normal or immunodeficient mice these cells do not form tumors. After proliferation over long time periods or after extensive expansion these T cells tend to lose their cytotoxic activity which cannot be reconstituted by addition of cells from active cultures of a different specificity. Accordingly, the specificity of the cytotoxic and proliferative response was investigated. The cytotoxic activity appears to be specific for the H‐2 SD antigens, while the proliferative response and also the activation of cytotoxicity in resting cultures is only triggered by lymphocyte activating determinants (LAD) coded either inside or outside the H‐2 region.The receptors for LAD on these allospecific T cells appear to be clonally distributed. This finding comes from the observation that old and therefore highly selected lines only react to some LAD while younger ones react to many others as well. A search for immunoglobulin on these functional and antigen‐specific thymus‐derived lymphocytes (T cells) was performed using surface radioiodination, immunoprecipitation and polyacrylamide gel electrophoresis combined with autoradiography. Using various antisera no or very little immunoglobulin molecules were found on these T cells. The small amount of immunoglobulin was attributed to a contamination of allogeneic spleen cells used to stimulate the T kil

ISSN:0014-2980    

DOI:10.1002/eji.1830070606

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractA rabbit antiserum against rat thymocyte membrane was studied using quantitative absorption analysis, and shown to contain a large amount of antibody against antigen(s) on lymphocytes but not liver, erythrocytes, kidney, heart, lung or brain tissue. Among lymphocytes the antigen(s) was at least 20‐fold more abundant on thymocytes or T lymphocytes than on bone marrow or B lymphocytes, and is thus referred to as a T lymphocyte antigen. In saturating binding studies with absorbed antiserum 120 000 molecules of antibody were bound per thymocyte.The T lymphocyte antigenic activity was effectively solubilized from thymocyte membrane by deoxycholate, and its hydrodynamic properties suggested that only one molecule (or a group of very similar molecules) express the activity. The S20,wand v̄ values of the antigen were 5.7 S and 0.73 ml/g, and the Stoke's radius was 6.2 nm; a molecular weight (including any bound deoxycholate) of 1 50 000 was calculated. All antigenic activity in deoxycholate extracts bound to a lentil lectin affinity column suggesting the antigen may be a glycoprotein. On serological and biochemical grounds the antigen was distinct from Thy‐1.In an appendix a method for determining the maximum binding of antibody per cell by absorption analysis is descr

ISSN:0014-2980    

DOI:10.1002/eji.1830070607

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractLinear density gradients were used to separate either unsensitized human peripheral blood lymphocytes or cells sensitized in mixed leukocyte culture (MLC), at different time points in the immune response. Testing of cells from the various density fractions for their ability to respond in MLC and cell‐mediated lympholysis (CML) revealed that (a) activity between individual fractions differed, as well as activity between individual fractions and a suspension of unfractionated cells, (b) although precursor cells of MLC and CML were maximally enriched in closely associated light density regions, their respective distribution profiles were strikingly different, and (c) the density of cells responding in MLC and CML differed depending upon the point of the immune response at which the cells were separated. Whereas effector cells were of light density relative to the precursor cells, putative memory cells for CML exhibited a high densit

ISSN:0014-2980    

DOI:10.1002/eji.1830070608

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractT cells from strain A primedin vitroto (C57BL/6 × A/J)F1[(B6 × A)F1] cells, respond better to restimulation by (B6 × A)F1than by B6 or a 1:1 mixture of A and B6 cells. The increase in the response to F1cells is specific and due to MLR determinants present on (B6 × A)F1cells but not on either of the parental cell types. (B6 × A)F1cells express more than one F1‐specific MLR determinant, and this expression is dependent upon products of alleles of at least two loci within the major histocompatibility complex (MHC). Responsiveness to these F1‐MLR determinants is apparently controlled by more than one locus within

ISSN:0014-2980    

DOI:10.1002/eji.1830070609

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractSupernatants from rat thymic epithelial cultures (TES) increased [14C]thymidine incorporation into rat thymocytes stimulated with phytohemagglutinin (PHA) or concanavalin A, whereas supernatants from nonthymic control tissue cultures had no effect. It was demonstrated that the increased mitogen responsiveness was at least partially due to an increase in the number of responsive cells. Furthermore, our data suggest that the target cell for TES resides among the cortisone‐sensitive population of thymocytes. The continuous presence of TES provided the best conditions for enhancement of mitogen stimulation. The addition of TES had very little effect on mitogen‐stimulated spleen and lymph node lymphocyte cultures.The data suggest that, in the presence of TES, a cortisone‐sensitive, PHA‐nonre‐sponsive subpopulation of rat thymocytes is induced to respo

ISSN:0014-2980    

DOI:10.1002/eji.1830070610

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY

摘要:

AbstractExposure of 2, 4‐dinitrophenyl (DNP)‐hemocyanin‐primed spleen cells to DNP‐conjugated pneumococcal polysaccharide (DNP‐S3)in vivoorin vitrorenders such cells unresponsive to DNP‐hemocyanin challenge following adoptive transfer. The unresponsiveness is hapten‐specific, independent of the presence of T cells and adherent cells, and not due to either toxic effect of S3 or carry‐over of tolerogenic amounts of cell‐bound DNP‐S3, and thus presumably represents a model of B cell tolerance. The degree of suppression induced depends upon the dose of the tolerogen and most strikingly on the duration of exposure of cells to the tolerogen. Thus 2 to 6 h exposure to DNP‐S3 has an insignificant effect on anti‐DNP responses, while 24 and 48 h exposuresin vitroandin vivoare highly suppressive. Such a dynamic process of tolerance induction suggests a “multiple hit” phenomenon, implying the generation of suppressive signals by repeated cycles of tolerogen‐receptor interactions. The process can be interrupted by removal of extracellular DNP‐S3, although this does not reverse the unresponsivenes

ISSN:0014-2980    

DOI:10.1002/eji.1830070611

出版商:WILEY‐VCH Verlag GmbH    

年代:1977

数据来源: WILEY