摘要:

AbstractThe murine monoclonal antibody (mAb) CB43, raised against the K‐562 erythroleukemia line, reacts with monocytes, tissue macrophages, thymocytes and with all the human lines tested but not with resting lymphocytes, large granular lymphocytes, granulocytes and erythrocytes. However, activated lymphocytes and natural killer cells express the CB43 antigen. Embryonic and fetal fibroblasts are positive, while adult fibroblasts are negative. Proximal convoluted tubules in kidney, epithelial cells in esophagus and breast, and sarcolemma in skeletal muscle are reactive with mAb CB43. This antibody can also bind to isolated guinea pig cardiac myocytes, and, furthermore, can induce a transient inotropic effect on isolated atria.The reactivity with different cell and tissue types and the functional effects of the CB43 mAb were reminescent of the 4F2/44D7 antibodies, shown previously to block Na/Ca2+exchange in heart and skeletal muscle. Co‐immunoprecipitation studies with CB43 and 44D7 mAb, using radiolabeled Daudi cells, revealed co‐migration of polypeptides of 87 and 38 kDa.However, the epitope recognized by CB43 is not present on the human heavy chain which bears the 44D7/4F2 epitope as demonstrated by the lack of reactivity of CB43 mAb with mouse L cells transfected with the 4F2 heavy chain gene. Thus, CB43 represents a newly described epitope present on the human light chain or dependent on the conformation of the human

ISSN:0014-2980    

DOI:10.1002/eji.1830190102

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractT cell activation induced via the CD3‐T cell receptor (TcR) complex, or by triggering of polyclonal antigen‐independent pathways, involves both interleukin 2 (IL 2) production and IL 2 receptor (IL 2R) expression and results in T cell proliferation. To assess the potential role of the IL 2 pathway in T cell development, growth and activation requirements of intrathymic T cell precursors were analyzed and correlated with the expression of IL 2R. In contrast to CD3‐TcR (either CD4 or CD8) mature thymic cells, CD3‐TcR‐CD1‐4‐8‐early prothymocytes constitutively expressed IL 2R and displayed IL 2‐mediated proliferation, which was inhibited by anti‐IL 2R monoclonal antibodies (mAb). Moreover, prothymocytes developed spontaneous proliferation in the absence of exogenous IL 2, which was also abrogated by blocking of IL 2R with specific mAb. The possibility that both IL 2 production and IL 2R expression are autonomously activated early in T cell development, before acquisition of the CD3‐TcR complex, led us to study the implication of alternative pathways of activation at this ontogenic stage. Triggering of the CD2 pathway with mAb against two different epitopes of the molecule (D66 and 9.6/T111) induced proliferation of CD3‐TcR‐prothymocytes in the absence of exogenous IL 2, while proliferation of CD3‐TcR mature thymocytes required IL 2 supplementation. These data suggest that polyclonal activation of the IL 2 pathway may be selectively operative at early stages of T cell development, being involved in the growth and differentiation of in

ISSN:0014-2980    

DOI:10.1002/eji.1830190103

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractPhosphorylation of protein kinase C (PKC) substrates in T lymphocytes was analyzed after stimulation with specific pairs of anti‐CD2 monoclonal antibodies (mAb) or an anti‐CD3 mAb. The results show that the appropriate stimulation of both CD2 or CD3 antigens results in phosphorylation of a 80‐kDa putative PKC substrate and that this phosphorylation event is sensitive to a PKC inhibitor, sphinganine. CD2‐ and CD3‐dependent phosphorylation was found to be strongly dependent on an extensive cross‐linking of surface antigens. The biological importance of cross‐linking of CD2 and CD3 was also evident for other biological responses such as interleukin 2 production and induction of an autocrine growth response. Finally, we also present evidence for interaction between the CD2 and CD3 signal transdu

ISSN:0014-2980    

DOI:10.1002/eji.1830190104

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractB2A2‐CD4‐8‐cells represent a rare subpopulation of thymocytes normally comprising 0.5% of the total adult thymus. These cells are known to express CD3‐associated T cell receptor (TcR) α/ß molecules. In the present study we have examined the functional capacity of α/ß heterodimers on B2A2‐CD4‐8‐cells. In the presence of monoclonal antibody (mAb) specific for either murine CD3 or TcR expressing the Vβ8‐encoded ß chain (F23.1), B2A2‐CD4‐8‐cells proliferated. Such proliferation was blocked by mAb to interleukin 2 receptor (IL 2R), suggesting an autocrine mechanism involving IL 2 production and subsequent utilization. IL 2 and also IL 3 production by mAb‐stimulated B2A2‐CD4‐8‐cells was directly confirmed. Furthermore, a panel of B2A2‐CD4‐8‐clones were derived to assess the role of the TcR in cytolysis. Many clones were isolated which killed Fc receptor‐bearing P815 target cells only in the presence of F23.1 mAb. Finally,in vivotreatment of neonatal mice with F23.1 mAb resulted in a marked reduction of Vβ8 B2A2‐CD4‐8‐thymocytes. Collectively, these results indicate that the TcR α/ß complex on CD4‐CD8‐B2A2‐cells is fully capable of transducing signals that lead to proliferation, lymphokine production and cytolysisin vitro, as well

ISSN:0014-2980    

DOI:10.1002/eji.1830190105

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractWe have found that approximately 10%–15% of tonsil, but not peripheral blood, T cells express the CD23 antigen following activation with 12‐O‐tetradecanoylphorbol 13‐acetate (TPA), phytohemagglutinin (PHA) or recombinant interleukin 4. The proliferative response of tonsil T cells is significantly increased when CD23 monoclonal antibodies (mAb) are present in the cultures. In contrast, no such proliferative augmentation is seen when peripheral blood T cells are cultured in this way. Supernatant (SN) of Epstein‐Barr Virus‐transformed B lymphoblastoid cell lines (EBVLCL), is found to have a similar co‐stimulatory effect on the proliferation of tonsil T cells to that seen with CD23 mAb. This effect is greatly diminished by preclearing SN with CD23 mAb. Similarly, SN from a CD23 L cell transfectant augments the proliferative response of tonsil T cells to both TPA and PHA. The CD23 molecule expressed by TPA‐driven T cell blasts appears identical in size to the 45‐kDa glycoprotein present on EBVLCL and activated B cells. In constrast, a 42‐kDa molecule is observed when CD23 is precipitated from T cells activated with PHA. The results presented here demonstrate that CD23 is expressed on activated tonsil, but not peripheral blood T cells and plays a role, via the binding of CD23 mAb and CD23 material, present in EBVLCL and CD23 transfectant SN, in the regulation of T cell proliferation in response to mitogens

ISSN:0014-2980    

DOI:10.1002/eji.1830190106

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractDNA from a panel of inbred strains of mice and colony bred mice, isolated from different geographical locations, was hybridized to mouse VpreB and λ5probes under stringent conditions, indicating sequence similarities greater than 80%. The probe for λ5detects one gene and the probe for VpreB detects two genes (VpreB1andVpreB2) in the inbred strains of mice examined under the stringency used. No restriction endonuclease fragment length polymorphisms (RFLP) were detected with the VpreB and λ5DNA probes among the inbred strains of mice using Bam HI and Hind III. Very few RFLP were detected amongMus musculussubspecies, and the intensity of the hybridization did not differ significantly with either DNA probe. The number of RFLP increased slightly when different species and subgenera were examined, and the intensity of the hybridization signal began to decrease in samples from the different subgenera, suggesting a slight decrease in sequence similarity for both VpreB genes with increased time of divergence. Fewer RFLP were detected with the λ5DNA probe. DNA from 11 different Mus species representing 4 subgenera, genetically isolated from laboratory mice for approximately 1–12 million years, continued to hybridize under high stringency conditions using both DNA probes. A comigrating λ5and VpreB restriction endonuclease fragment was detected in most of the samples examined, suggesting the close physical linkage of VpreB1 and λ5is maintained within the genus Mus. These results suggest thatVpreB1, VpreB2and λ5have been present for over 12 milli

ISSN:0014-2980    

DOI:10.1002/eji.1830190107

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractPrediction, identification and analysis of T cell epitopes in protein antigens has become a central theme in fundamental and applied immunology. However, while for the characterization of linear B cell epitopes the so‐called Pepscan procedure was found to be extremely effective, no such technique has so far been available for T cell studies. Recently, we described the identification and localization of a T cell epitope in a mycobacterial 65‐kDa shock protein in the model of adjuvant arthritis. This was done by molecular cloning and conventional solid‐phase synthesis techniques. We now show that the delineation of such a T cell epitope and its further characterization can be accomplished in a much more rapid and efficient manner by a modification of the existing Pepscan technique. We show for the first time that several hundreds of peptides, simultaneously synthesized in an automated way on activated polyethylene rods, can be easily recovered from these rods in adequate quantities, enabling a systematic analysis of T cell epitopes. Synthesis of sequentially overlapping peptides along the 65‐kDa protein revealed that the adjuvant arthritis T cell clones are fully stimulated by peptides that comprise a minimal sequence of seven residues, corresponding to positions 180–186 in the sequence of the 65‐kDa protein ofM. bovis Bacillus Calmette Guerain(BCG). Detailed examination of the epitope by peptides containing a single amino acid substitution showed that, apart from one conservative replacement (Glu → Asp), the requirement for the native residue at all positions in peptide 180–186 was absolute for full T cell stimulation. Their indispensability was confirmed with deletion and insertion peptides. It is concluded that the occurrence of indifferent or spacer residues in a minimal stimulatory sequence, as observed by others, is not a general feature of

ISSN:0014-2980    

DOI:10.1002/eji.1830190108

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractCyclosporin A (CsA) is used as a clinical immunosuppressive agent. Despite its immunosuppressive potential, some studies involvingin vivoadministration of cyclosporin have failed to verify the immunosuppressive activity of this agent. The present study investigates the effect of different concentrations of CsA addedin vitro, or of different doses of CsA administeredin vivo, on the ability of murine spleen cells to produce interleukin 2 and to generate cytotoxic T lymphocytesin vitrowhen stimulated with TNP‐self or H‐2 alloantigens. The results indicate that self Ia‐restricted T helper (Th) cells are more sensitive to lower doses of CsA than Thcells that are allorestricted. Thus, doses of CsA were found (15–30 mg/kg) that inactivated self Ia‐restricted Thfunction, but not other Thor effector function. This Thcell defect could be partially correctedin vitroby addition of Thcell factors to the sensitization cultures. A higher dose (75 mg/kg) of CsA inactivated all detectable T cell responses, and this defect was not corrected by addition of Thcell factors. T cell function returned to normal levels within two weeks of cessation of CsA at all three doses of CsA tested. The selective loss of L3T4 Thfunction at the lower doses of CsA was associated with a radiosensitive, Ly‐2 suppressor T cell that was selective in its action on self Ia‐restricted Thcell function. Loss of all T cell function at the higher dose of CsA was associated with a radioresistant non‐T suppressor cell that inactivated all T cell function tested. These results are discussed with respect to the selective dose‐dependent effects of CsA on Thsubsets, on the activation of suppressor cells with similar selectivity, and the implications of these findings on the use of CsA to prevent rejection of

ISSN:0014-2980    

DOI:10.1002/eji.1830190109

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractA polyclonal CD34‐8‐WT31‐cell line (termed SFG) was utilized for mice immunization in order to produce monoclonal antibodies (mAb) specific for the T cell receptor (TcR) γ/δ. Hybrid supernatants were screened for their ability to induce SFG cells (but not conventional TcR α/β CTL lines) to kill the murine Fc receptor‐positive P815 target cell line. Three hybrids, termed G1, A13 and F11, were isolated according to this screening. By indirect immunofluorescence G1 mAb reacted with 65% of SFG cells, while A13 stained 26% and F11 75% of cells. Double‐fluorescence analysis revealed that G1 and A13 mAb identify two distinct, non‐overlapping subsets of cells present in the SFG cell line. The reactivity of the mAb was also analyzed on a panel of representative TcR α/β clones. G1 mAb reacted with 5 clones, that were also stained by the previously described BB3 mAb (recognizing the disulfide‐linked form of TcRα/β). These clones failed to react with A13 and δ‐TCS‐1 mAb (the latter of which is known to react with a non‐disulfide‐linked form of TcR α/β). Out of six clones that reacted with A13 mAb, four were also δ‐TCS‐1, whereas two were δ‐TCS‐1‐and none of them reacted with G1, (or BB3) mAb. In contrast to the mAb above, F11 brightly stained the G1A13‐clones and more weakly the G1‐A13 clones. Moreover, F11 efficiently triggered both types of clones to kill the P815 target cells while G1 and A13 were able to trigger only G1 or A13 clones, respectively. None of the mAb above reacted with a large number of CD3WT31 clones. Antibodyinduced surface antigen modulation experiments indicated that molecules recognized by G1, A13 and F11 were physically associated on cell surface with CD3 determinants. In addition, immunoprecipitation followed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis analysis (performed on125I‐surface‐labeled TcRα/β clones) revealed that molecules recognized by G1, A13 and F11 displayed an apparent mol. wt. corresponding to that of CD3‐associated TcR molecule

ISSN:0014-2980    

DOI:10.1002/eji.1830190110

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY

摘要:

AbstractIt has been hypothesized that the selective recognition of tissue‐specific endothelial cell molecules helps determine thein vivodistribution of lymphoid effector cells by controlling the extravasation of their circulating precursors. Here we report (a) immunofluorescence studies of the cell surface phenotype of human lamina propria lymphocytes (LPL), including staining with monoclonal antibody Hermes‐1, which defines a 90‐kDa lymphocyte surface glycoprotein involved in recognition of high endothelial venules (HEV); and (b) functional analyses of the ability of LPL to bind to HEV in frozen sections of mucosal lymphoid tissues (appendix or Peyer's patch)vs.peripheral lymph nodes. Essentially all LPL bear the Hermes‐1 antigen, over 90% at levels comparable to those of circulating PBL. As a population, LPL display a quantitative preference for adherence to mucosal HEV, binding 0.8–1.5 times as well as PBBL to mucosal HEV, but only 0.1–0.5 times as well to HEV in peripheral lymph nodes. Of particular interest was the behavior of the lymphoblast fraction, which typically constituted 3–7% of LPL. These cells, defined by size, consisted of a mixture of T cells and surface IgA blasts. One hundred percent were Hermes‐1bright, and they bound 4–8 times more efficiently to mucosal HEV than PBL while failing to bind detectably to lymph node HEV. LPL binding to mucosal HEV involves the gp90Hermes, since the monoclonal anti‐gp90 antibody, Hermes‐3, and a polyclonal anti‐gp90 antiserum inhibit the binding of small LPL and of LP blasts. The remarkable efficiency and specificity of binding by LP blasts may reflect retention of homing properties of the blood‐borne precursors of these blasts and is discussed in relation to the capacity of immunoblasts in mesenteric nodes and in thoracic duct lymph to traffic selectively to mucosal lymphoid and extralymphoid sites. The demonstration of organ‐specific endothelial cell recognition by LP lymphoblasts provides considerable support for the concept that selective interactions with endothelium play an important role in directing the distribution of activate

ISSN:0014-2980    

DOI:10.1002/eji.1830190111

出版商:WILEY‐VCH Verlag GmbH    

年代:1989

数据来源: WILEY