摘要:

AbstractAnti‐peroxidase antibody (Ab)‐secreting hybrids have been produced by fusion of peroxidase (PO)‐immunized mouse lymph node cells and immunoglobulin (Ig)‐secreting P3‐X63‐Ag8 (X63) myeloma cells. Identification of Ab‐secreting hybrids can be performed as early as day 5 after cell fusion by the hemolytic plaque assay. Immediately after identification, hybrids were directly isolated, by means of a micropipette, into Terasaki microchambers containing nutrient medium and a thymocyte filler layer. The yield of secreting hybrids is improved by using this procedure.All the cells of the PO 772 C2 clone show the same ultrastructural pattern and immunocytological properties; they are proplasmocytes, as are the parental X63 cells; they present intracisternae Ab and show no Ig or Fc receptors at the cell surface. Over 90% of viable PO 772 C2 cells form specific plaques. Isoelectric focusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis show that the cells of this clone secrete Ab; the secreted Ig are formed with χ and γ1chains from the parental X63 cells and specific L and H chains from the lymphoid parent. These biological investigations demonstrate the relative stability of the PO 772 C2 clone secreting anti‐pe

ISSN:0014-2980    

DOI:10.1002/eji.1830090102

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThe cellular requirements for the generation of cytotoxicity in mixed lymphocyte reaction (MLR) across an H‐2K mutant difference were analyzed. Treatment of C57BL/6 lymphocytes with either anti‐Lyt‐1 or anti‐Lyt‐2 serum and complement strongly reduced their capacity to mount a cytotoxic response against the B6.C‐H‐2bamutant. Almost complete reconstitution of the cytotoxic response occurred when a mixture of anti‐Lyt‐1 and anti‐Lyt‐2‐treated cells was allowed to respond. Once cytotoxicity was generated, only anti‐Lyt‐2 serum affected it. It is concluded that in the cytotoxic response to the ba mutant, Lyt‐1 helper cells collaborate with Lyt‐2,3 killer cell precursors in the generation of Lyt‐2,3 killer cells. Lyt‐1,2,3 cells play, if any, a minor role in the generation of cytotoxicity.By comparison, the capacity to generate killer cells in MLR against an H‐2K + IA difference was only affected by anti‐Lyt‐2 and not by anti‐Lyt‐1 serum, indicating that this response is relatively independent of he

ISSN:0014-2980    

DOI:10.1002/eji.1830090103

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractRabbit immunoglobulin antigen receptor molecules were analyzed by electrophoresis in sodium dodecyl sulfate polyacrylamide gels. By sequential precipitation, using first anti‐μ and then anti‐L chain antisera, two different immunoglobulins of similar molecular weight could be demonstrated. After tryptic digestion, two fractions were identified: an IgMsand an Fab fragment, the latter appearing after a few minutes of incubation. Thus, as in man and in the mouse, two main immunoglobulin antigen receptors were found in the rabbit. One receptor on rabbit lymphocytes is an IgMsmolecule, and the other is easily split in the hinge region like human and mouse IgD recep

ISSN:0014-2980    

DOI:10.1002/eji.1830090104

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractA number of defined metabolites and derivatives of cyclophosphamide (CY) were compared with the parent compound for their capacity to induce suppression of humoral antibody responsesin vivoandin vitroand to inhibit the regeneration of surface immunoglobulin (sIg) receptors on B cells subsequent to capping with anti‐Ig serum. Both functions were inhibited by exposing spleen cellsin vitroto the most active compounds (4‐hydroperoxycyclophosphamide and phosphoramide mustard) in concentrations of 10 μg/ml or less. Although these inhibitory activities were found to be restricted to those molecules with demonstrable alkylating activity, they are nevertheless reversible and not dependent on events leading to cell death.Inhibition with microsomally activated CYin vitrorendered splenic B cells hyper‐susceptible to tolerance induction by levan, although in the absence of this antigen they recovered full responsiveness to it within 7–10 days. Since lethally irradiated mice repopulated with adult bone marrow cells do not regenerate normal responsiveness to polysaccharide antigens in less than 50–100 days (Howard, Moreno, Hale and Vicari,Eur. J. Immunol.1977.7: 431.), it is considered that the rapid recovery by CY‐treated spleen cells involves reversal of suppression in B cells and not renewal from stem cells. Our previous proposal (Shand and Howard,Nature1978.271: 255.) that impairment of B cell receptor regeneration by CY is causally related to its capacity to promote B cell tolerance induction by thymus‐independent antigens is supported by th

ISSN:0014-2980    

DOI:10.1002/eji.1830090105

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThe frequency and specificity of clones of cytotoxic lymphocytes (CL) produced when (CBA × C57BL)F1spleen cell populations were cultured with 2,4,6‐trinitrophenyl (TNP)‐modified syngeneic F1cells, was examined. The frequency of clones which lysed F1‐TNP targets was 1/3.3 × 104spleen cells, and the frequency of clones which lysed the modified parental cells, CBA‐TNP and C57BL‐TNP was 1/6.7 × 104and 1/2.9 × 105spleen cells, respectively. Using a clonal analysis of the specificity of the CL, it was shown that the majority of the clones of CL which lysed the two modified parental targets, were specific for one or the other of the targets. Activity against modified allogeneic DBA/2‐TNP targets was also detected. The activity against DBA/2‐TNP targets was due mainly to clones of CL which were specific for DBA/2‐TNP targets. Only a minor part of the activity was due to clones which were cross‐reactive for both F1‐TNP and

ISSN:0014-2980    

DOI:10.1002/eji.1830090106

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractRabbit kappa light (L) chain allotypes are controlled by the allelic genes b4, b5, b6, b9and a recently described allele b4v. The product of the b4vgene differs from that of b4by at least two amino acid substitutions in the constant region. A serologic distinction between the b4 and b4vallotypes has now been detected by a radioimmune assay using one of six anti‐b4 sera tested. The distinction was enhanced by fractionation of this antiserum on an immunoadsorbent containing cottontail rabbit IgG. IgG with L chains of the b4vtype are deficient in their ability to inhibit binding of b4 IgG to the antibody preparation. L chains isolated from b4 and b4vIgG samples could not be distinguished by this assay indicating that interaction with an H chain is required for expression of the L chain determinants that differentiate b4 from b4

ISSN:0014-2980    

DOI:10.1002/eji.1830090107

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThymocytes have been studied at various stages during ontogeny in relation to their responsiveness to β adrenoceptor agonists and ability to bind L‐[propyl‐2,3‐3H]dihy‐droalprenolol ([3H]DHA), a specific radioligand of the β adrenoceptor. Specific [3H]DHA binding and the activity of an isoproterenol‐sensitive adenylate cyclase were compared and correlated between (14 to 20‐day) fetal mouse thymocytes and young adult thymocytes. Preliminary experiments show that [3H]DHA binding to thymocytes demonstrated the kinetics, affinity and stereospecificity expected of binding to adenylate cyclase‐coupled β adrenoceptors. Similarly, isoproterenol was shown to selectively increase intracellular adenosine 3′: 5′‐cyclic monophosphate (cAMP) levels and was antagonized by propranolol (a β adrenoceptor antagonist), but not by phentolamine (an a adrenoceptor antagonist), nor by lignocaine (a local anesthetic). The rises in fetal thymocyte cAMP levels found after stimulation with isoproterenol were of greater magnitude than in adult thymocytes. The number of [3H] DHA‐binding sites in both fetal and adult thymocytes was the same (Bmax= 50 fmol/2 × 106cells). However, the affinity of the binding sites for [3H] DHA was less for the adult cells than the fetal cells (with KDvalues of 8.0 and 2.2 nM, respectively); this was reflected in the amount of [3H] DHA bound being up to 8 times grea

ISSN:0014-2980    

DOI:10.1002/eji.1830090108

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThe distribution of two heavy chain subgroups, VHa and VHy, on rabbit peripheral blood lymphocytes was examined by double membrane immunofluorescence. Fluorescent anti‐a 1 and anti‐y 33 were found to react with separate B cell populations; no doubly stained cells were observed. Further evidence for the independent expression of genes controlling the VHa and VHy subgroups was obtained by neonatal suppression of a 2 or y 33 in a2y33/a3y−heterozygous rabbits. Suppression of VHa did not affect the expression of VHy, nor did the suppression of VHy affect the expression of VHa. The expression of a single VHgene per B cell is in marked contrast to the simultaneous expression of multiple CH

ISSN:0014-2980    

DOI:10.1002/eji.1830090109

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThe relationship between surface IgM (sIgM) and surface IgD (sIgD) was examined on small lymphocytes in the adult murine bone marrow or prepubertal spleen. Cells were sorted on the basis of different sIgM levels by a fluorescence‐activated cell sorter (FACS) and relabeled for sIgD or total sIg by a sandwich technique using125I‐labeled protein A and radioautography. For detecting sIgD, an anti‐δ allotype reagent was used in congenic mice. Cells lacking sIgM in the bone marrow or spleen were also found to be sIgD−; thus, sIgD appeared only in the presence of sIgM. Weak sIgM‐bearing cells in the bone marrow also had no sIgD indicating that sIgD appeared only after the acquisition of a significant level of sIgM. Subsequently, the incidence of sIgD+cells increased in fractions showing increasing sIgM levels indicating the acquisition of new sIgD by “sIgM only” cells with increasing maturation levels in the bone marrow. In marrow lymphoid cells expressing both Ig isotypes, sIgM and sIgD levels increased in parallel, possibly with increasing maturation level. In the spleen, the incidence of sIgD+cells among various cell fractions showing different sIgM levels was found constant. However, spleen cells bearing both receptors, showed a small increase in the sIgD level with increas

ISSN:0014-2980    

DOI:10.1002/eji.1830090110

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY

摘要:

AbstractThree mouse thymocyte subpopulations with differing sensitivity to dexamethasone were characterized by size and density. Distribution patterns were determined for thymocytes during normal development and during regeneration after treatment with dexamethasone. From these, the subpopulation proportions were calculated and cell population kinetics were evaluated. Medium‐sized low density cells (type III) were least sensitive to dexamethasone and showed a relatively slow regeneration rate. The small cells of intermediate density, “early cortical” cells (type II), exhibited the most rapid regeneration rate, while the growth rate of the small cells of high density (type I) was intermediate. Cells of intermediate and high density were relatively sensitive to dexamethasone. The ratio of the phytohemagglutinin to concanavalin A (Con A) response increased after dexamethasone treatment with the increase in the proportion of type III cells. Con A responses were attributed to type II and type III cells. A tentative multipathway model for intra‐thymic T cell development is presented. Large cells, not confined to a certain trajectory in the density gradient, may represent a pool of proliferating cells of the other thre

ISSN:0014-2980    

DOI:10.1002/eji.1830090111

出版商:WILEY‐VCH Verlag GmbH    

年代:1979

数据来源: WILEY