摘要:

AbstractThe F1progeny of autoimmune NZB and normal SWR mice uniformly develop severe and accelerated lupus nephritis. The (SWR × NZB)F1mice produce an oligoclonally expanded population of nephritogenic anti‐DNA autoantibodies that share a recurrent cross‐reactive idiotype (Id564), use highly homologous VHgenes and surprisingly have the CHregion allotype of the normal SWR parent. From extensive library analyses, we isolated 15 SWR germ‐line genes which are most closely related to the pathogenic autoantibody VH564 gene and which also belong to the NPb subfamily of J558 VHgenes. We found that the pathogenic VHgenes are probably somatic variants of a SWR germ‐line VHgene, SW6—3, and they have several basic amino acid substitutions, in addition to those already present in the SW6—3 germ‐line gene. Since these pathogenic autoantibodies are not detectable in the sera of the normal SWR mice despite the presence of the SW6—3 gene, strong selection and expansion of B cells expressing the SW6—3 VHgene is probably occurring in (SWR × NZB)F1lupus‐prone mice. We also isolated eight germ‐line genes from the NZB mouse which are homologous to SW6—3. The autoimmune NZB parent that rarely develops nephritis lacks the SW6—3 gene, but has several highly homologous germ‐line VHgenes that would encode less cationic antibodies. These results establish a correlation between structure and pa

ISSN:0014-2980    

DOI:10.1002/eji.1830220302

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractIgG isolated on protein A‐Sepharose from pools of normal sera from various mouse strains were examined by immunoblotting for reaction with self antigens. Homogenates of the major mouse organs,i.e.brain, skin, spleen, kidney, adrenals, thymus, heart, muscle and liver were used as the source of autoantigens. IgG stained at least 220 bands on the immunoblots. The antigens corresponding to these bands were tentatively identified by molecular mass estimation and referenced to computerized mouse protein data banks. IgG mainly recognized enzymes but it also stained intracellular structural constituents and surface molecules implicated in the functioning of the immune system. The validity of this identification was confirmed by analyzing purified antigens from mouse or other animal species by immunoblotting and enzyme immunoassays. Furthermore, extracts of125I‐surface‐labeled cells were immunoprecipitated with IgG in the liquid phase or immobilized on beads. The proteins precipitated migrated to the same positions as those precipitated by specific monoclonal antibodies (mAb), such as class I α chain and β2‐microglobulin, class II α and β chains, CD3, CD4 and CD8 antigens. The results obtained with several enzyme immunoassay procedures using cell membrane extracts, specific mAb and normal IgG further supported the specific interaction of IgG with Ia, CD4 and CD8 molecules. Affinity chromatography indicated that at least 20% of normal mouse IgG possess polyreactive autoantibody function. Dissociation constants of these IgG were calculated for some autoantigens and found to be in the range of 2 × 10−6−7 × 10−6M. It is concluded that normal mouse IgG exhibit autoreactivities similar to those previousl

ISSN:0014-2980    

DOI:10.1002/eji.1830220303

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA large number of Vβ8 gene‐encoded cDNA were analyzed from peripheral CD4+and CD8+T cell subsets of T cell receptor (TcR) α chain‐transgenic mice. This analysis demonstrates that a limited repertoire of TcR β chains are co‐expressed with the transgenic α chain. Most importantly, certain Vβ8‐Jβcombinatons were found exclusively in one of the subsets and, in some cases, subset‐specific differences were localized to the VDJ junctional region of the β chain genes. In contrast, CD4−CD8−transgenic T cells, as well as CD4+and CD8+T cells from normal littermate controls, were found to express diverse β chain repertoires. The present study suggests that β chains with distinct structural characteristics are expressed in the CD4+and CD8+subsets, respectively. Moreover, the data suggest that the same structural constraints do not apply to the population of CD4

ISSN:0014-2980    

DOI:10.1002/eji.1830220304

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractEndogenous superantigens of mice, encoded by mammary tumor virus proviral integrants, induce intrathymic deletion of entire T cell populations that express specific Vβgene products, a phenomenon proposed to be important in self‐tolerance and prevention of toxic responses to exogenous microbial superantigens. Evidence for the presence of Vβselecting/deleting endogenous superantigens in other species is lacking. We report here that rats do not exhibit endogenous superantigen‐induced Vβclonal deletions despite their strong response to bacterial superantigens. These findings indicate that endogenous superantigens are not obligatory in Vβrepertoire

ISSN:0014-2980    

DOI:10.1002/eji.1830220305

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractTo study the structural basis for specificity and affinity of cytotoxic T lymphocytes for major histocompatibility complex/peptide complexes, we have employed a cytotoxic T lymphocyte (CTL)‐mediated immunoselection approach to obtain H‐2Kbstructural mutants which are resistant to lysis by a Kb‐specific alloreactive CTL clone. In this study we describe the Kbstructural mutant, designated R8.60.14, recovered following immunoselection using the CD8‐dependent CTL clone 60 as a selective agent. Although serologically unaltered with respect to Kbexpression, R8.60.14 is not recognized by CD8‐dependent, Kb‐specific CTL. DNA sequence analysis revealed a single Glu → Lys amino acid substitution at position 222 in the Kbα3domain of this variant. To determine if a direct correlation exists between CD8 dependence of a Kbspecific CTL and its failure to respond to R8.60.14, we examined the lytic response against R8.60.14 by CD8‐independent, Kb‐specific CTL obtained from long‐term culture in the presence of anti‐CD8 monoclonal antibody, 3.155. CD8‐independent CTL exhibit no difference in their response against the R8 parent and R8.60.14 variant. This study demonstrates unequivocally that Kb‐specific recognition of R8.60.14 by CD8‐independent CTL is unaltered, while the response by CD8‐dependent CTL is completely abrogated. Thus, the sole basis for emergence of this variant in the CTL‐mediated immunoselection approach used in this study resides in the alteration of a single CD8‐binding site residue at position 222 in the Kbα3domain. The functional importance of this Glu222residue for the interaction between the CD8 molecule on CD8‐dependent CTL and the Kbα3domain is further reinforced by virtue of the recovery of the R8.60.14 variant on the basis of its resistance to lysis by a CD8‐dependent CTL clone in th

ISSN:0014-2980    

DOI:10.1002/eji.1830220306

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractDBA/2‐derived mouse tumor cells were transfected with the H‐2Kbgene. Naturally processed minor histocompatibility (H) peptides were extracted from both transfected and non‐transfected cells by acid elution, and were separated by high‐performance liquid chromatography. Kb‐restricted minor H epitopes corresponding to H‐4band mapki, both encoded by non‐major histocompatibility complex genes of DBA/2, were readily detected by the respective cytotoxic T lymphocyte in peptides extracted from Kb‐transfected, but not from non‐transfected or Db‐transfected cells. Titration experiments indicated at least 3000‐fold less copies of correctly processed Kb‐restricted epitopes in cells without Kbas compared to cells with Kb. Since we estimate the copy number of Kb‐restricted H‐4bepitopes in Kb‐expressing transfectants to be less than 1000 per cell, the pool size of H‐4bepitopes correctly processed in the absence of Kbshould

ISSN:0014-2980    

DOI:10.1002/eji.1830220307

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractAntibody‐mediated ligation of the CD3/T cell antigen receptor (TcR) activates phospholipase C (PLC) via a tyrosine kinase signaling pathway that requires expression of the transmembrane tyrosine phosphatase CD45. In normal T cells, CD3‐mediated PLC activation is significantly augmented by co‐ligation of CD3 with the CD4 co‐receptor; however, unlike CD3‐associated tyrosine kinases, antibody‐induced activation of the CD4‐associated tyrosine kinase p56lckdoes not require CD45 expression. To explore the role of CD45 in the CD3 and CD4 activation pathways further, we examined the effect of CD3/CD4 cross‐linking on tyrosine phosphorylation and activation of phospholipase C in CD45−mutant cells of the T cell leukemia line HPB.ALL. In accord with previous observations, anti‐CD3 stimulation of the CD45‐deficient cells failed to activate tyrosine kinases, or PLC as measured by mobilization of intracellular calcium. However, we show here that ligation of CD3 with CD4 leads to tyrosine phosphorylation of PLCγ1 and elevation in the intracellular free Ca2+concentration in CD45−cells that is in excess of that seen in CD45+cells. Since CD4 stimulation alone did not activate PLC, a component of the CD3 signaling pathway must be independent of CD45. Anti‐CD4‐induced tyrosine phosphorylation and activation of CD4‐associated lck was also enhanced in CD45−cells, suggesting that increased lck activation compensates for the defect in CD3/TcR signaling, such that interaction of the CD3 signaling pathway with the CD4‐associated pathway activates PLC even in the absence of CD45. The data demonstrate that the requirement for CD45 in coupling CD3/TcR to the PI‐PLC activation cascade is not absolute, but rather substantiates a role for CD45 in modifying molecular interac

ISSN:0014-2980    

DOI:10.1002/eji.1830220308

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractClassical RT1‐A class I and RT1‐B class II major histocompatibility complex (MHC) molecules were purified from DA (RT1av1) spleens, and the individual chains separated and purified by preparative polyacrylamide gel electrophoresis in sodium dodecyl sulfate. LEW (RT11) rats were immunized with the pure class I heavy chain, the RT1‐B α chain and the RT1‐B β chain with the aim of priming to indirect allorecognition (i.e.after processing and presentation of DA MHC chains on LEW antigen‐presenting cells) in the absence of any priming to direct allorecognition (i.e.to whole, undenatured, dimeric DA MHC molecules). LEW rats immunized with each of the three DA MHC chains produced alloantibodies to these chains, suggesting that indirect allorecognition did occur, because of the requirement for cognate recognition of B cells by T helper cells. This also demonstrated polymorphism of all three chains between the DA and LEW strains. The antibodies to the isolated, denatured MHC chains did not react to the whole MHC molecules on DA cells, with the possible exception of very weak reactions in some class I heavy chain‐immunized rats. DA skin grafts placed on LEW recipients immunized with each of the DA MHC chains were rejected in an accelerated fashion. Following DA skin grafting, there was an accelerated production of antibodies to whole, undenatured class I MHC molecules, even in the LEW rats preimmunized with RT1‐B α and RT1‐B β chains. These data suggest that indirect allorecognition can play an important role in the effector mechanisms of allograft rejection, and demonstrate T helper priming as one possible mechanism whereby this

ISSN:0014-2980    

DOI:10.1002/eji.1830220309

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractThe expression of γ/δ T cell antigen receptors (TcR) in T cell lines or clones derived from tumor‐infiltrating lymphocytes (TIL) from patients with solid tumors was investigated. γ/δ TcR T cell lines were derived from TIL from patients with Wilms tumor, sarcoma or metastatic melanoma by stimulation with autologous tumor cells alone and recombinant interleukin 2 and they exhibited nonspecific cytotoxicity against autologous and allogeneic tumor cells, or cells of the K562 or the MEL21 tumor cell lines. Two T cell lines were derived from a patient with Wilms tumor. One of them expressed a non‐disulfide‐linked γ/δ TcR using the 60‐kDa γ chain, whereas, the other expressed a disulfide‐linked γ/δ TcR. A T cell line was derived from a patient with sarcoma and expressed a disulfide‐linked γ/δ TcR, whereas, a T cell line derived from a patient with melanoma expressed a non‐disulfide‐linked γ chain of 62 kDa. Several T cell clones were developed from patients with metastatic melanoma or Wilms tumor and expressed either disulfide‐ or non‐disulfide‐linked γ/δ TcR. Northern analysis of RNA from certain of these clones revealed a full‐length γ chain transcript, whereas, the α or β chain transcripts were either absent or truncated. These T cell clones exhibited nonspecific cytotoxicity. Both disulfide‐ and non‐disulfide‐linked TIL T cell lines and clones expressed the δ TCS1 determinant. γ/δ TcR+cells in freshly prepared TIL from these patients were present in low proportions (<5%) and their δTCS1/δ1 ratios were within the range observed in the peripheral blood of normal donors. These results demonstrate that both disulfide‐and non‐disulfide‐linked γ/δ TcR are expressed on T cell lines and clones derived from TIL from solid tumors. Non‐disulfide‐linked γ/δ TcR using the 56–66‐kDa γ chain are frequently found on TIL‐derived T cell lines and clones. These 56–66‐kDa γ chains are rarely expressed on T ce

ISSN:0014-2980    

DOI:10.1002/eji.1830220310

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY

摘要:

AbstractA major goal of current candidate malaria vaccines is to stimulate the expansion of clones of malaria‐specific lymphocytes. We have examined thein vitroT cell responses of a group of malaria exposed and non‐exposed adult Caucasian donors to recombinant circumsporozoite (CS) proteins, one of which is undergoing clinical trials, to blood‐stage parasites, and to synthetic peptides copying the CS protein and defined blood‐stage proteins. In nearly all individuals tested, CD4 T cell proliferation or lymphokine production occurred in response to whole parasite or CS protein stimulation, and T cells from many individuals responded to synthetic peptides. T cell responses were major histocompatibility complex‐restricted, and stimulation of T cells with malaria parasites or CS protein did not appear to expand a population of T cell receptor γ/δ cells. Malaria‐specific responses were independent of prior malaria exposure, and in some cases exceeded the magnitude of response to tetanus toxoid. Specific T cells are present in high frequency in the peripheral blood of many donors who have never been exposed to malaria. Although malaria‐specific CD4 T cells play an important role in immunity, these data question whether vaccines need to stimulate such cells, and focus attention on other aspects of malaria immunity which may be more critical to a suc

ISSN:0014-2980    

DOI:10.1002/eji.1830220311

出版商:WILEY‐VCH Verlag GmbH    

年代:1992

数据来源: WILEY