bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of memory and virgin B cell clones in hyperimmune animals
Authors: Berek Claudia , Jarvis John M. , Milstein Cesar 
Published: March 2007

AbstractTo study the long‐term memory response, BALB/c mice were allowed to rest for over a year after a secondary immunization with the hapten 2‐phenyl‐oxazol‐5‐one (phOx). For the tertiary immunization two different protocols were used. In one protocol mice were injected i.v. and 3 days later spleen cells were fused to a nonproducing hybridoma line. PhOx‐specific hybridomas were established and the sequence of the heavy and light chain mRNA was determined. This tertiary response resembled the diversity pattern of the secondary response with a further increase both in somatic mutations and in the average dissociation constant. The high number of somatic mutations demonstrates the persistence of memory B cell clones over a long time period. In the second protocol mice were boosted with an i.p. injection of alumprecipitated antigen phOx and 7 or 14 days later spleen cells were fused. Sequence analysis of heavy and light chain mRNA showed that these tertiary response antibody molecules had surprisingly few somatic mutations, indicating an activation of virgin B cell clones in these hyperimmunized animals. The maturation of these newly stimulated B cell clones seems to follow somewhat similar rules to those found for the primary response. It appears therefore that the two immunization protocols reflect the response of memory and virgin B cells, respectively.
The role of L3T4+ cells in the pathogenesis of lupus in lpr‐bearing mice. I. Defects in the production of interleukins 2 and 3
Authors: Santoro Thomas J. , Lehmann Kathrin R. , Batt Rebecca A. , Kotzin Brian L. 
Published: March 2007

AbstractMice which bear the lpr gene spontaneously develop autoimmune syndromes characterized by massive expansion of an unusual T cell subset which is phenotypically Thy‐1+, L3T4−, Lyt‐2−, B220+. The mutant T cells are refractory to stimulation with mitogenic lectins and, by implication, are thought to be solely responsible for the defects in lymphokine production manifested by lpr mice. The contribution of the remaining L3T4+ T cell subset to the latter derangements has not been previously examined and is the focus of this study. We found that abnormalities in concanavalin A‐induced interleukin 2 and 3 production in the spleens of MRL‐lpr/lpr and C57BL/6.lpr mice occurred in the presence of limited infiltration with B220+, L3T4− T cells. Mixing experiments indicated that B220+ T cells were not suppressive. Furthermore, lpr spleen cells enriched for L3T4+ cells and depleted of sIg+, B220+ and Lyt‐2+ cells demonstrated reductions in lymphokine production which were comparable to those seen in unfractionated preparations. Spleen cells from C57BL/6.lpr mice, enriched for L3T4+ cells, were also markedly impaired in a mixed leukocyte reaction in response to stimulator cells from the class II major histocompatibility complex mutant bm12. The results indicate that the aberrations in lymphokine production and proliferation in the spleen cells of lpr mice involve not only B220+ T cells but also L3T4+ cells and suggest a potential role for the L3T4+ subset in the pathogenesis of lupus in lpr‐bearing mice.
Comparison of the clonal diversity of the B cell repertoires in adult mice that differ in the expression of cell surface IgD
Authors: Fultz Marion J. , Finkelman Fred D. , Metcalf Eleanor S. 
Published: March 2007

AbstractTo determine whether the expression of surface IgD (sIgD) influences the extent of the expressed B cell repertoire, the clonal diversity of the B cell population in mice treated chronically with anti‐IgD (delta) antibodies has been compared with the B cell repertoire observed in control animals, using the splenic focus limiting dilution B cell assay. The results show that the phosphorylcholine (PC)‐specific B cell precursor frequency in anti‐delta antibody‐treated mice is increased when compared with that of control mice. Isotype and idiotype (T15) analyses of PC clonal products from anti‐delta antibody‐treated and control mice revealed no distributional differences. Analyses of the 2,4‐dinitrophenyl (DNP)‐ and fluoresein isothiocyanate‐specific B cell repertoires confirmed that the equal or increased precursor frequencies observed in anti‐delta antibody‐treated mice are not specific for the PC antigen. The increased precursor frequency of B cells from anti‐delta antibody‐treated mice was not the result of increased homing of B cells from anti‐delta antibody‐treated mice to recipient spleens, since B cells from control mice homed twice as well to recipient spleens as did B cells from anti‐delta antibody‐treated mice. Other studies demonstrated that (a) on average, antibody‐secreting clones were generated more slowly when B cells from anti‐delta antibody‐treated mice were used as a source of precursors than B cells of control mice and (b) both sIg− spleen cells and sIg+ spleen cells from anti‐delta antibody‐treated mice generated a higher frequency of specific antibody‐secreting clones than did the corresponding populations from control mice. These observations suggest that a population of sIgM+sIgD− B cells exists that resembles sIgD+ B cells rather than neonatal or xid B cells in its ability to generate responses to PC and suggests that the sIgM+ sIgD− B cells from anti‐delta antibody‐treated mice are more responsive than are sIgM+IgD+ B cells, regardless of antigenic specificity, to the stimuli provided in the splenic focus system. Finally, this study suggests that the expression of sIgD does not influence the extent of the expressed B cell repertoire.
Role of cellular and humoral immunity and helper cell involvement in permissiveness to infection by Schistosoma mansoni
Authors: Mendlovic Fela , Tarrab‐Hazdai Rebeca , Arnon Ruth 
Published: March 2007

AbstractCellular and humoral parameters were studied in permissive (mouse) and nonpermissive (rat) animals during the first few weeks following infection by Schistosoma mansoni. Comparison was made between the antigen‐induced proliferation of lymphocytes of the two species. Extract of cercaria, schistosomula and adult worms obtained from infected mice served as the test antigen in 3 and 6 days incubation in vitro thymidine uptake assay. Both spleen and thymus cells of mice and rats differed in their reactivity with the schistosome antigens, but the difference was much more pronounced in the thymocytes. In this case, whereas cells obtained from mice were not induced to proliferate by any of the antigens, thymocytes of the infected rat showed specific increasing proliferation rates as a function of time after infection.In the rat, a subset of T cell population, the T helper cell, appears to be involved in the immune response, as established by the use of anti‐helper monoclonal antibody W3/25. In the presence of these antibodies the immune reactivity of the rat thymocytes with antigens from different stages of the parasite was markedly reduced. The effect of W3/25 antibodies was observed not only in vitro, in the lymphocyte proliferation assay, but also in vivo, by a significant increase in the extent of infection in the W3/25‐treated rats, as compared to untreated controls.Differences between the two hosts were also observed in their humoral immune response against the schistosome antigens, as manifested by complement‐dependent cytotoxicity. In these assays mouse sera were more effective than rat sera. When autologous complement was evaluated, mouse complement had a higher cytotoxic effect than rat complement in killing of the parasite. Both sources of complement were less effective than guinea pig complement in causing antibody‐mediated cytotoxicity.
CD4 monoclonal antibody pairs for immunosuppression and tolerance induction
Authors: Qin Shixin , Cobbold Steve , Tighe Helen , Benjamin Richard , Waldmann Herman 
Published: March 2007

AbstractA pair of rat anti‐mouse CD4 monoclonal antibodies (mAb) have been selected which bind to different epitopes of the molecule. Both the mAb are rat IgG2b and show clear synergistic activity in complement lysis in vitro. When injected together in vivo, they exhibit an improved immunosuppressive effect, compared to each antibody alone, on allogeneic graft rejection, humoral responses and on tolerance induction. Limiting dilution analysis indicates that the in vivo depletion of interleukin 2‐producing cells is improved using both mAb by 2–3‐fold over that obtained with the individual antibodies. As little as 60 ng per mouse of the CD4 antibody pair was sufficient to allow the induction of tolerance to human γ‐globulin, even without elimination of the CD4+ cells. The results suggest that appropriate antibody pairs may be good candidates for effective immunosuppressive serotherapy in man.
Selective up‐regulation by interferon‐γ of surface molecules of the Ly‐6 complex in resting T cells: the Ly‐6A/E and TAP antigens are preferentially enhanced
Authors: Dumont Francis J. , Dijkmans Roger , Palfree Roger G. E. , Boltz Robert D. , Coker Lisa 
Published: March 2007

AbstractSurface molecules encoded by the murine Ly‐6 locus can transduce triggering signals in T cells and thus may play important roles in T cell function. Previously, we found that Ly‐6 molecules are up‐regulated by interferon (IFN)‐α/β in resting T cells. Here, we examined the possible influence of IFN‐γ on these molecules. Purified T cells from C57BL/6 (Ly‐6.2) and BALB/c (Ly‐6.1) mice were incubated in vitro with recombinant murine IFN‐γ and the expression of Ly‐6 antigens was measured by flow cyto‐fluorometry. It was found that both Ly‐6A/E and T cell‐activating protein (TAP) molecules are markedly enhanced while Ly‐6C is less affected. Under the same conditions, other T cell surface molecules showed no or marginal changes. The effect of IFN‐γ on Ly‐6A/E and TAP expression reached a maximum with as little as 10 U/ml and required only 18–24 h of incubation. Moreover, the enhancement of Ly‐6A expression induced by IFN‐γ was stable for at least 5 days. Analysis of T cell subsets further revealed that IFN‐γ‐induced augmentation of Ly‐6A (C57BL/6 mice) involves both Lyt‐2+ and L3T4+ cells while the increase of Ly‐6E (BALB/c mice) is more pronounced in Lyt‐2+ cells. The functional consequence of these phenotypic alterations was evaluated by studying the mitogenic responses of T cells to antibody‐mediated Ly‐6 cross‐linking in the presence of phorbol myristate acetate. Pretreatment of resting T cells with IFN‐γ dramatically increased the responses to anti‐Ly‐6A and anti‐Ly‐6E monoclonal antibodies. IFN‐γ treatment also boosted the stimulation induced by anti‐TAP monoclonal antibody when this stimulation was performed under suboptimal conditions. Therefore, IFN‐γ selectively up‐regulates the Ly‐6A/E and TAP activation pathways in resting T cells. We speculate that this effect may contribute to the immunoregulatory activities of IFN‐γ.
Human CD3+4−8−WT31−T lymphocyte expressing the putative T cell receptor γ‐gene product. A limiting dilution and clonal analysis
Authors: Moretta Lorenzo , Pende Daniela , Bottino Cristina , Migone Nicola , Ciccone Ermanno , Ferrini Silvano , Mingari Maria Cristina , Moretta Alessandro 
Published: March 2007

AbstractThe small peripheral blood CD3+ T cell population lacking both CD4 and CD8 surface antigens has been analyzed in the present study. Enriched CD3+4−8− populations were obtained by depletion with anti‐CD4 or anti‐CD8 monoclonal antibodies (mAb) and complement. The resulting populations contained >99% CD2+ cells, whereas CD3+ represented approximately 50%. Virtually all of the cells were CD4−8− and did not react with the WT31 mAb, specific for a framework determinant of the α/β T cell receptor (TCR). In order to analyze the molecular nature of CD3‐associated molecules in CD3+WT31− populations, cells were stimulated with 0.5% phytohemagglutinin (PHA) for 24 h and expanded for an additional 7–14 days in interleukin 2 (IL2). The resulting cells were >95% CD3+ and expressed neither CD4/CD8 nor WT31 antigen.Cell surface iodination followed by cross‐linking and immunoprecipitation with anti‐CD3 mAb showed that CD3‐associated molecules consisted of a major 45‐kDa band and a minor band of 43 kDa. Thus, whereas CD3‐associated molecules isolated from polyclonal CD3+WT31+ populations (expanded in IL 2 under the same culture conditions) appeared as diffuse bands, CD3‐associated molecules isolated from CD3+WT31− populations displayed a homogeneous molecular mass. Northern blot analysis revealed the presence of mRNA for the TCR γ chain whereas the mRNA for the α chain was mostly represented by a truncated (1.2 kb) form. Also small amounts of a nonproductive mRNA for the β chain were detected. Freshly isolated CD3+WT31−‐enriched populations proliferated in response to PHA and concanavalin A, moreover, IL 2 was detected in the culture supernatants after cell stimulation. By applying culture conditions which allow virtually all T cells to undergo clonal expansion, approximately 1/3 CD3+WT31− were clonogenic. In addition, the large majority of proliferating microcultures lysed the K562 cell line and about half the natural killer (NK)‐resistant fresh melanoma target cells. A large number of clones derived from CD3+WT31− enriched populations by limiting dilution has been further analyzed. More than 95% of the clones were CD3+4−8−WT31−; 12/15 clones analyzed in more detail displayed NK activity and 6/15 lysed melanoma cells; in addition, all lysed P815 target cells in the presence of PHA, thus indicating that all the clonogenic CD3+WT31− cells have a cytolytic potential.
Synthesis and expression of MHC class II molecules in the absence of attached invariant chains by recombinant interferon‐γ‐activated bone marrow‐derived macrophages
Authors: Schneider Franz‐Josef , Opel Beate , Ballhausen Wolfgang , Henkes Wolfgang , Steinlein Peter , Reske Konrad 
Published: March 2007

AbstractPure populations of in vitro propagated bone marrow‐derived macrophages are constitutively Ia negative. Co‐culturing of these cells with recombinant interferon‐gamma (rIFN‐γ) resulted in the appearance of high amounts of Ia antigens at the cell surface of essentially all cells. The continuous presence of the stimulus was a prerequisite for sustained Ia expression because removal of the stimulus resulted in rapid decline of surface Ia.Two‐dimensional (2D) gel analysis (1D isoelectric focusing, 2D sodium dodecyl sul‐fate‐polyacrylamide gel electrophoresis) of class II molecules synthesized by rIFN‐γ‐stimulated bone marrow macrophages (BMMΦ) revealed that, in contrast to class II complexes hitherto described, BMMΦ‐derived I‐A and I‐E subregion‐encoded subunits are synthesized without invariant chains. The invariant chain‐deficient α,β heterodimers are expressed at the cell surface in high proportions demonstrating that their correct assembly and transport to the cell surface is accomplished in the absence of invariant chains. The lack of invariant chains appears not to be due to a failure of rIFN‐γ to induce transcription of the γ‐chain gene because rIFN‐γ‐induced, in contrast to uninduced, BMMΦ accumulate high levels of invariant chain‐specific transcripts as evidenced by Northern blot analysis. These findings suggest that translation of γ‐chain‐specific mRNA is blocked in BMMΦ for as yet unknown reasons. Alternatively, newly synthesized γ chains might have escaped their regular intracellular maturation pathway as a result of unidentified modifications mediated by altered posttranslational processing mechanisms.
Histamine‐producing cell‐stimulating activity. A biological activity shared by interleukin 3 and granulocyte‐macrophage colony‐stimulating factor
Authors: Dy Michel , Schneider Elke , Gastinel Louis‐Noel , Auffray Charles , Mermod J. J. , Hamburger J. 
Published: March 2007

AbstractThe histamine‐producing cell‐stimulating factor (HCSF) was first described as a lymphokine which is produced during secondary mixed leukocyte culture and which induces increased histamine synthesis by murine hematopoietic cells. It has been shown that it is different from interleukin 3 (IL3), despite the fact that pure IL3 expresses HCSF activity. Our results provide evidence that this factor (constitutively produced by the P388 D1 cell line) is identical with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) i.e.: (a) physicochemical properties of HCSF and GM‐CSF, such as molecular weight, isoelectric charge, hydrophobicity and behavior during affinity chromatography, are indistinguishable and both activities coelute during all biochemical purification procedures; (b) increased bone marrow cell histamine synthesis induced by P388 D1‐derived HCSF is inhibited by anti‐GM‐CSF antiserum; (c) the GM‐CSF cDNA probe hybridizes with a poly(A)+RNA from P388 D1 cells while no hybridizing signal was obtained with poly(A)+RNA from WEHI‐3 and from P815 cells. On the other hand, the IL3 cDNA probe hybridizes with a 1.0‐kb poly‐(A)+RNA from WEHI‐3 but not with those from P388 D1 and P815. Moreover, well known sources of GM‐CSF, such as lung conditioned medium and semi‐purified GM‐CSF from phytohemagglutinin‐induced supernatant of the murine T lymphoma LBRM‐33‐5 A4 (preparation devoid of IL 3), as well as recombinant murine GM‐CSF, induce increased histamine synthesis by hematopoietic cells. All these results demonstrate that, in our culture conditions, the P388 D1 cell line spontaneously produces GM‐CSF which is responsible for the P388 D1‐induced HCS activity. Consequently, the latter is a property shared by the two distinct hematopoietic growth factors acting on the less committed cells, i.e. IL 3 and GM‐CSF, whereas M‐CSF or G‐CSF are unable to induce histamine production. Interestingly, IL 4 which is known to support established mast cell line proliferation cannot induce HCS activity. In addition, none of the other cytokines tested, such as IL1, IL2, interferons or tumor necrosis factor can express HCS activity. This expression seems to be a specific property of IL3 and GM‐CSF.
Differential regulation of T cell receptor gamma genes in immature thymocyte populations
Authors: Kinnon Christine , McGuire Kathleen L. , Rothenberg Ellen V. 
Published: March 2007

AbstractImmature thymocytes that lack both Lyt‐2 (CD8) and L3T4 (CD4) expression can respond rapidly to stimulation with phorbol ester and calcium ionophore by expressing some gene products characteristic of mature, activated T cells. Here we studied the effect of such short‐term stimulation on the number of copies per cell of RNA for components of the T cell receptor complex. Although, upon stimulation, mRNAs for T cell receptor β chain accumulated to higher levels, the cells did not rapidly increase their expression of α‐chain transcripts from rearranged or germ‐line genes. Transcripts from the Cγ1 (Cγ13.4) and Cγ2 (Cγ10.5) genes were differentially regulated. The rarer Cγ1 transcripts were strongly induced, while the initially abundant Cγ2 transcripts showed a modest decrease in transcripts per cell within 24 h. Thus, the ratio of these two transcripts could be shifted dramatically prior to any significant change in the cellular composition of the population. These results suggest regulatory processes that may contribute to the observed expression of γ products in vitro or in normal development.
A monoclonal antibody (HML‐1) defining a novel membrane molecule present on human intestinal lymphocytes
Authors: Cerf‐Bensussan Nadine , Jarry Anne , Brousse Nicole , Lisowska‐Grospierre Barbara , Guy‐Grand Delphine , Griscelli Claude 
Published: March 2007

AbstractA monoclonal antibody, HML‐1, was produced by fusion of NSI myeloma cells with spleen cells of a mouse immunized with isolated human intestinal intraepithelial lymphocytes (IEL). Immunofluorescence studies of isolated cells, as well as immunoperoxidase staining of tissue sections, indicated that HML‐1 labeled all the various subsets of human intestinal IEL, approximately 40% of lamina propria T cells, 30% mesenteric lymphoblasts and some lymphocytes in other mucosae, particularly IEL. Conversely, it revealed only rare cells in all other lymphoid compartments. Analysis by polyacrylamide gel gradient electrophoresis showed that HML‐1 precipitated two major noncovalently bound components of approximate mol. masses of 105 and 150 kDa from human IEL. HML‐1 thus defines a novel human membrane antigen present on a subpopulation of lymphocytes preferentially associated with epithelia, and particularly with the intestinal epithelium. The characteristics of this human antigen are very similar to those of an antigen we had previously described in the rat. The possible functional role of this novel class of lymphocyte membrane antigens as well as the nature of the mechanism that triggers their expression remain to be elucidated.
Differential requirements for the processing and presentation of soluble and particulate bacterial antigens by macrophages
Authors: Ziegler H. Kirk , Orlin Christine A. , Cluff Christopher W. 
Published: March 2007

AbstractThe requirements for antigen processing and presentation by macrophages using various forms of antigens derived from Listeria monocytogenes have been studied. Antigen presentation was monitored by T cell‐macrophage binding and interleukin production using T cells from Listeria monocytogenes‐infected mice and specific T cell hybridomas. Antigen processing requirements were defined by three criteria: (a) inhibition by lysosomotropic agents, NH4Cl and chloroquine; (b) kinetic relationships between antigen uptake and antigen presentation; and (c) antigen presentation by macrophages pre‐fixed with glutaraldehyde. In comparing heat‐killed Listeria monocytogenes (HKLM) with soluble listerial proteins (SLP), the presentation of SLP was less sensitive to lysosomotropic agents, showed faster antigen processing kinetics than with HKLM and could occur using pre‐fixed macrophages. Transitions between particulate and soluble forms had dramatic influences on processing requirements. Antigens associated with HKLM could be converted to soluble forms which did not require processing by preculture with macrophages and also by physical (e.g. sonication) and chemical (sodium dodecyl sulfate) treatments in the presence of protease inhibitors. Conversely, antigen processing was required when SLP were converted to a particulate form by covalent binding to latex beads. Analysis of SLP by molecular sieve chromatography and preparative SDS‐polyacrylamide gel electrophoresis revealed that high molecular weight proteins (> 60 kDa) could be presented by prefixed macrophages without prior processing. We conclude that the transition from a particulate to soluble antigenic form can be a significant antigen processing event.