bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thymic immune response gene function in radiation chimeras reconstituted with purified hemopoietic stem cells
Authors: Kast W. Martin , Voordouw Arie C. , Leupers Tine , Visser Jan W. M. , Melief Cornelis J. M. 
Published: March 2007

AbstractThymectomized (C57BL/6[B6] × bm1)F1 mice and thymectomized (B6 × bm12)F1 mice were engrafted with neonatal parental thymus of either B6 type [H‐2b mouse, Sendai virus cytotoxic T cell (Tc) responder] or bm1 type (H‐2Kb mutant, Sendai virus Tc nonresponder) and B6 type (H‐Y Tc responder) or bm12 type (H‐2 I‐Ab mutant, H‐Y Tc nonresponder), respectively. All mice were irradiated and reconstituted with highly purified syngeneic pluripotent hemopoietic stem cells. All types of thymus engraftment resulted in a restored T cell immunocompetence. The Tc reaction to Sendai virus in (B6 × bm1)F1 mice engrafted with both responder type B6 and nonresponder, type bm1 neonatal thymus allowed maturation of Sendai‐specific, H‐2Kb‐restricted Tc. For the Tc reaction to H‐Y, only responder type B6 thymus restored the Tc response, whereas this was not achieved with nonresponder type bm12 thymuses. We conclude from this study that in this radiation stem cell chimera system the radioresistant component of the thymus dictates major histocompatibility complex (MHC) specificity and immune response phenotype of T cells restricted to class II MHC molecules but not of T cells restricted to class I MHC molecules.
In vitro studies on human IgD I. Sources and characteristics of “externalized” IgD in tonsil lymphocyte cultures
Authors: Litwin Stephen D. , Zehr Bradley D. 
Published: March 2007

AbstractAs part of a broader analysis into the function of IgD, and especially into the role of human IgD‐secreting cells, fresh human tonsil lymphocyte cultures were analyzed. The goals were to define the origins of “externalized” supernatant IgD and to examine its relationship to spontaneous Ig secretion of IgG, IgM and IgA. Assayable IgD was found by 24 h in cultures without added mitogens. “Externalized” IgD comprised a small fraction (1.6–1.8%) of supernatant Ig when compared to the fraction of IgD‐containing cells (≈ 10%): IgD appears to disappear rapidly in vitro. Initial experiments employing irradiation and chemical inhibitors of protein synthesis suggested that “externalized” IgD was produced de novo during culture rather than representing preformed or cytophilic Ig. Most significantly, tonsil cultures with higher IgD values (> 20 ng IgD/106 cells, day 7) showed convincing evidence that secreted IgD was a major source for “externalized” IgD. This evidence included (a) the amount of “externalized” IgD depended on viable culture conditions; (b) radioincorporated 35S appeared as a visible IgD band on sodium dodecyl sulfate‐polyacrylamidegel electrophoresis (SDS‐PAGE) gels; (c) “higher” IgD cultures showed increased numbers of IgD‐Ig‐containing plasma cells, and IgD,λ in excess of IgD, x; both events are associated with IgD secretion. In cultures producing high amounts of IgD, IgD secretion appeared to be spontaneous rather than induced and was independent of the polyclonal spontaneous Ig secretion of other Ig isotypes. Low titers of inhibitable IgD isotype anti‐phosphorylcholine antibodies but not IgD isotype anti‐polyribotol phosphate antibodies were present in tonsil supernatants: both were present in matched sera.Other laboratories have directed attention to the striking and possibly selective participation of human tonsil lymphocytes in IgD synthesis using other approaches. Present results supplement and expand earlier data and support the practical value of analysis of short‐term cultured tonsil lymphocytes. Differentiation to IgD‐secreting cells is suggested to be an active, underestimated and putatively an important part of the immune response in the human tonsil.
In vitro studies on human IgD II. IgD‐secreting cells preferentially elaborate IgD, λ molecules
Authors: Litwin Stephen D. , Zehr Bradley D. 
Published: March 2007

AbstractThe “IgD paradox” describes the unexpected finding that, despite a predominance of kappa (x) light (L) chains on the surface of IgD+ human B cells, the majority of monoclonal IgD proteins are of lambda (λ) type. This potentially informative phenomenon appears to be based on a preferential association between delta (δ) heavy (H) and λ L chains of IgD‐secreting cells. The current studies analyze the phenomenon in vitro. Initial assays on tonsil “spent” supernatants showed that the higher IgD‐“externalizing” cultures displayed progressively elevated IgD,λ/x ratios due to parallel shifts in total IgD and IgD,λ while IgD,x remained stable. The cells of the same higher‐IgD cultures demonstrated that individual IgD‐containing cells had a predominance of λ chains in contrast to IgM‐containing cells of the same cultures using fluorochrome‐antibody double staining. Certain tonsil culture IgD‐containing cells remarkably appeared to have exclusively λ chain. These same tonsils show evidence of IgD secretion (Litwin, S. D. and Zehr, B. D., Eur. J. Immunol. 1987. 17: 483); thus, these data align preferential δ‐λ chain association with IgD‐secreting normal tonsil B cells in vitro and emphasize the usefulness of IgD,λ/x ratio in monitoring IgD secretion. In another approach the relationship between the cellular location of IgD and the preferential δ‐λ chain association was studied using Triton X‐114‐partitioned cell lysates. IgD,λ/x ratios were one or less in the detergent phase (membrane‐enriched fraction) consistent with expected IgD,x predominance in membrane IgD. In contrast, the aqueous phase (intracellular‐enriched fraction) of IgD‐secreting cultures had 2–4 times higher supernatant IgD,λ/x ratios. The restriction of high IgD,λ/x ratios to intracellular fractions and supernatants of IgD‐secreting cultured cells parallels the predicted distribution of secretory IgD. In sera studies, the correlation between total IgD and IgD,λ/x ratio values was consistent with secreted sera IgD showing preferential λ chain expression. It was concluded that the phenomenon of δ‐λ chain preferential association is (a) expressed in vitro as well as in vivo; (b) a property of normal, nonmalignant human IgD‐secreting B cells; and (c) closely related to the secretory form of IgD. In certain cultures, the δ‐λ chain preference was so striking as to imply limited heterogeneity of the IgD immune response.
Murine lupus anti‐DNA antibodies cross‐react with the hapten (4‐hydroxy‐5‐iodo‐3‐nitrophenyl)acetyl, but immunization‐induced anti‐DNA antibodies do not
Authors: Zouali Moncef , Migliorini Paola , Stollar David B. 
Published: March 2007

AbstractThe antigen‐binding selectivity of 2 sets of anti‐DNA antibodies from autoimmune mice and from normal mice was examined. Eighteen affinity‐purified anti‐DNA autoantibodies from MRL‐lpr/lpr mice were examined for binding to the haptens azoben‐zenearsonate, phosphorylcholine, (4‐hydroxy‐3‐nitrophenyl)acetyl and (4‐hydroxy‐5‐iodo‐3‐nitrophenyl)acetyl (NIP). Five of these autoantibodies bound to NIP‐protein conjugates. In contrast, none of 12 monoclonal antibodies to single‐stranded DNA or left‐handed Z‐DNA induced by immunization of BALB/c and C57BL/6 mice with nucleic acid antigens reacted with the tested haptens.In a reciprocal test of the relationship between anti‐DNA and anti‐NIP binding, we examined 24 monoclonal antibodies to NIP, from various strains of mice, for binding to DNA. One such antibody from a BALB/c mouse also bound to DNA. These results are discussed in the context of the mechanisms underlying autoantibody hyperproduction.
Prevention of experimental autoimmune uveoretinitis by active immunization with autoantigen‐specific monoclonal antibodies
Authors: De Kozak Yvonne , Mirshahi Massoud , Boucheix Claude , Faure Jean‐Pierre 
Published: March 2007

AbstractPreimmunization of Lewis rats with anti‐S antigen (S‐Ag) monoclonal antibodies (mAb) led to protection against experimental autoimmune uveoretinitis (EAU) induced by this retinal autoantigen. High titers of anti‐idiotypic (anti‐Id) antibodies were raised against three mouse mAb, S2D2 (IgG2b), S6H8 (IgG2a) and S7D6 (IgG1), directed at S‐Ag. An almost complete prevention was observed in S2D2 mAb‐immunized animals while a partial protection was achieved with S6H8 and S7D6 mAb. No detectable anti‐Id antibody nor disease prevention was observed in rats immunized with the mAb S9E2 (IgG2a) which only recognizes bovine and sheep S‐Ag, or with control mAb of the same isotypes irrelevant to S‐Ag. The mAb treatment did not modify the level of the whole polyclonal antibody response to S‐Ag. These results suggest an important role in the pathogenesis of EAU for the epitopes recognized by S2D2‐S6H8 and S7D6 in the S‐Ag molecule. The success of anti‐Id immunization for autoimmune disease suppression may depend on the identification of relevant epitopes.
Differentiation in the murine B cell lymphoma I.29: individual μ+ clones may be induced by lipopolysaccharide to both IgM secretion and isotype switching
Authors: Alberini Cristina , Biassoni Roberto , Deambrosis Sandro , Vismara Daniela , Sitia Roberto 
Published: March 2007

AbstractCells from the monoclonal B cell lymphoma I.29 expressing surface IgM (μ+) are capable of differentiating in vitro to IgM secretion and of switching to IgA or IgE production in response to lipopolysaccharide (LPS) stimulation. To determine whether a single μ+ B cell is capable of undertaking both differentiative pathways (isotype switch and plasma cell differentiation) I.29 μ+ cells were cloned by limiting dilution and a panel of clones were analyzed by immunofluorescence, endogeneous labeling and Northern blotting. While 100% of the clones could differentiate toward IgM secretion, only a proportion of them (> 70%) also switched to IgA and/or IgE production. Certain clones switched preferentially to a specific isotype. Taken together with the observation that Cγ genes were never the target of switching in our experiments, these data suggest that individual μ+ clones from the I.29 lymphoma are “precommitted” as for their switching potentials.The subclones that showed a high frequency of switching to IgA transcribed the germ line Cα gene(s), suggesting a role for chromatin structure in determining the isotype switch specificity. Switch variant clones expressing either IgA or IgE on the cell surface were isolated and found capable of further differentiating toward Ig secretion in response to LPS. On the contrary, we could not induce switch to IgA in IgE‐producing cells. Unlike μ+ and α+ cells, all the switch variant clones expressing IgE tested by endogenous labeling constitutively secreted large amounts of IgE in the supernatants even in the absence of LPS stimulation.
Comparison of the effects of 1,25‐dihydroxyvitamin D3 on T lymphocyte subpopulations
Authors: Rigby William F. C. , Yirinec Bruce , Oldershaw Robert L. , Fanger Michael W. 
Published: March 2007

AbstractPrevious studies have demonstrated that 1,25‐dihydroxyvitamin D3 (calcitriol) is a potent inhibitor of human T lymphocyte proliferation. It has been reported that only CD4+ cells are sensitive to the anti‐proliferative action of calcitriol. To further evaluate this observation, we first performed cell cycle analysis of unfractionated phytohemagglutinin‐stimulated peripheral blood mononuclear cells (PBMC) in the absence or presence of calcitriol. The CD4/CD8 ratio was similar between control and treated cells for each phase of cycle (G0→G1, S, G2 + M), suggesting that calcitriol did not selectively block proliferation of either T cell subpopulation. Secondly, the growth‐inhibitory activity of calcitriol on PBMC selectively depleted of either CD4+ or CD8+ cells was comparable to that observed with unfractionated PBMC. Furthermore, the induction of transferrin receptors was inhibited by calcitriol to a comparable degree in each T cell subset, suggesting that equivalent inhibition of transition into late G1 was observed. Finally, calcitriol inhibited the proliferation of highly purified T cell subsets (> 99% pure) to equivalent degrees. These data suggest that T cell subsets defined by either the CD4 or by the CD8 antigen are both sensitive to the growth inhibitory effects of calcitriol.
Hybrid antibody‐mediated lysis of virus‐infected cells
Authors: Staerz Uwe D. , Yewdell Jonathan W. , Bevan Michael J. 
Published: March 2007

AbstractPreviously, cytotoxic T lymphocytes (CTL) had only been focused by hybrid antibodies to normal, cell‐surface proteins and haptenated surface structures. In this report, we extend the application of this technology to mediate lysing of virus‐infected cells by nonspecific CTL. Heteroconjugated antibodies between the anti‐T cell antigen receptor antibody, F23.1, and monoclonal antibodies against either the hemagglutinin or nucleoprotein of the influenza virus PR/8 were constructed. We show in the present report that these bispecific constructs can target virus‐infected cells for lysis according to the specificity of the virus‐protein reactive monoclonal antibodies. Furthermore, even a virus protein that is only expressed in small quantities on the cell surface, such as nucleoprotein, can be exploited as target structure for heteroconjugated antibodies. These studies show that hybrid antibodies can focus a CTL response on virus‐infected cells which might in the future be used to mount an immune response in situations without sufficient normal cellular defense.
Constitutive production of B cell differentiation factor‐like activity by human T and B cell lines
Authors: Kanowith‐Klein Susan , Saxon Andrew , Uittenbogaart Christel H. 
Published: March 2007

AbstractA lymphokine demonstrating human B cell differentiation factor (BCDF)‐like activity was isolated from immature (MOLT‐4f, CCRF‐CEM and CCRF‐HSDB‐2) and mature (HUT‐78) malignant human T lymphoid cell lines and from human B lymphoblastoid cell lines (BJAB and ALL‐7031‐B). All the cell lines were grown long term in serum‐free medium. This BCDF‐like activity has a molecular mass in the range of 40–60 kDa and stimulates immunoglobulin synthesis of cell lines capable of producing IgA (GM‐1056), IgG (GM‐1500 and CESS) and IgM (CBL#3). It was not produced by a myeloid cell line. We were only able to identify the differentiation activity produced by the T and B cell lines by using appropriate molecular mass fractions from the serum‐free medium as controls. This BCDF‐like activity is different from that of the human BCDF so far described as it has a higher molecular mass and is constitutively produced by malignant T lymphoid cell lines which are human T cell leukemia virus‐I negative and by B lymphoblastoid cell lines.
Isotypic pattern of the polyclonal B cell response during primary infection by Plasmodium chabaudi and in immune‐protected mice
Authors: Falanga Pierre Barthélémy , D'imperio Lima Maria Regina , Coutinho Antonio , Da Silva Luiz Pereira 
Published: March 2007

AbstractThe primary infection by P. chabaudi induces an increase of the numbers of splenic immunoglobulin (Ig)‐secreting B cells in both athymic and euthymic BALB/c mice. The isotypic pattern of the polyclonal response is restricted only in euthymic mice where IgG2a, IgG2b and IgM plaque‐forming cells (PFC) predominate. In immunized animals, protected against a parasite challenge, the isotypic pattern of splenic PFC is completely different, the IgG1 and IgM isotypes constituting the main part of the response. Reinoculation of immune‐protected animals induces a PFC response which is dose dependent and accentuates the characteristic isotypic profile of the immune‐protected mice.
The induction of class I HLA by interferon‐α is independent of the cell cycle, but the expression is enhanced by a G1/S block
Authors: Erusalimsky Jorge D. , Gilmore David , Milstein Cesar 
Published: March 2007

AbstractThe induction of class I HLA expression by interferon‐α (IFN‐α) was studied in lymphoid cells arrested or traversing different stages of the cell cycle. Exponential cultures of MOLT‐4 cells and the MOLT‐4 cell variant YHHH were treated with the cell cycle inhibitors aphidicolin and colcemid to obtain cell populations arrested in G1/S and G2/M, respectively, and also cells traversing from S to M and vice versa. Cytofluorimetry with the monoclonal antibody YTH/76.3 (which specifically detects those class I molecules which are most susceptible to IFN‐α induction) was used to quantitate the class I HLA response to IFN‐α. The results showed that the response to IFN‐α is not restricted to a given stage of the cell cycle. These studies also revealed that when the cells were arrested at G1/S, the absolute level of class I HLA expression was enhanced 2–3‐fold, both in the presence or absence of either IFN‐α or IFN‐γ. Therefore, even when absolute levels changed, the ratio of IFN‐induced expression to basal expression remained constant at all cell cycle stages. The level of expression of another surface antigen (the CD1 antigen HTA‐1) was not affected by the G1/S block. The results were confirmed by dot blot hybridization of poly (A)+ RNA using cDNA‐specific probes. These findings suggest that the effect of IFN‐α is continuous throughout the cell cycle but that a G1‐dependent event determines the extent of class I HLA expression, and leads to a synergistic superinduction by IFN in G1/S‐arrested cells.
Modulation of neutrophil expression of C3b receptors (CR1) by soluble monomeric human C3b
Authors: Porteu Françoise , Mir Amparo , Halbwachs‐Mecarelli Lise 
Published: March 2007

AbstractUpon incubation at 37°C with purified human C3b (500 μg/ml), polymorphonuclear neutrophils (PMN) were found to express up to 50% more C3b receptors (CR1) than PMN incubated with buffer alone. This up‐regulation of CR1, assessed by the binding of radiolabeled CR1‐specific monoclonal antibody, was dependent on the dose of C3b, occurred within 10–20 min and was stable for at least 90 min. PMN incubated with C3b also demonstrated enhanced CR1‐dependent binding functions, such as EC3b rosette formation and phagocytosis of EIgGC3b particles. C3b at a concentration of 500 μg/ml induced up to 90% increase in the attachment or the phagocytic index. However, CR1 remained unable to promote phagocytosis of EC3b intermediates. Fc receptor‐mediated functions were unaffected by the treatment with C3b. The active factor was characterized as monomeric C3b and, in particular, shown to be distinct from C5a. C3b purified by anion‐exchange fast protein liquid chromatography on a Mono Q column or eluted from a monoclonal anti‐C3b‐Sepharose retained its modulating activity, while native C3 or C3 fragments such as iC3b, C3c or C3d,g were ineffective.
T cell receptor β chain gene rearrangements and Vβ gene usage in horse cytochrome c‐specific T cell hybridomas
Authors: Baumhüter Susanne , Fasel Nicolas , Corradin Giampietro , Guardiola John 
Published: March 2007

AbstractComparison of T cell receptor α and β‐chain genes in murine major histocompatibility complex (MHC) class I and class II‐restricted T cell clones and hybridomas recognizing different antigens indicates that no simple correlation exists between the observed antigen/MHC specificity and the expression of certain α and β‐chain heterodimers. We have attempted to establish a possible correlation by analyzing T cell receptor β chain gene rearrangements and Vβ gene usage in five T cell hybridomas with identical antigen/MHC specificity and another hybridoma recognizing a different antigenic determinant in association with the same restriction molecule. We report here that in each of the five clones a uniquely rearranged β chain gene is expressed in combination with at least two different Vβ gene segments. The presence of the differently rearranged T cell receptor β chain genes correlated with the finding of distinct fine specificity pattern of antigen recognition in each of the hybridomas. Interestingly, two hybridomas specific for different epitopes showed identical β chain D‐J rearrangements indicating that the differences might be encoded by the α chain gene or/and the Vβ gene element.
Effect of stereospecificity of chemically synthesized lipid A‐subunit analogues GLA‐27 and GLA‐40 on the expression of immunopharmacological activities
Authors: Kumazawa Yoshio , Ikeda Satoru , Takimoto Hiroaki , Nishimura Chiaki , Nakatsuka Mitsunobu , Homma J. Yuzuru , Yamamoto Akihiro , Kiso Makoto , Hasegawa Akira 
Published: March 2007

AbstractTumor necrosis factor (TNF)‐inducing, mitogenic, polyclonal B cell activation (PBA), macrophage activation and antiviral activities of chemically synthesized lipid A‐subunit analogues, GLA‐27 and GLA‐40, were investigated. The structure of GLA‐27 comprises 4‐O‐phosphono‐D‐glucosamine carrying tetradecanoyl and 3‐tetradecanoyloxytetradecanoyl [C14‐O‐(C14)] groups as the 3‐O‐ and 2‐N‐acyl substituents, respectively. GLA‐40 is a 1‐deoxy compound of GLA‐27. The activities of stereoisomers, (R) and (S) forms at the C3 position of the C14‐O‐(C14) group, of both compounds were also investigated. TNF‐inducing activity of the (S) isomers of GLA‐27 and GLA‐40 was stronger than that of the (R) isomers while the (R) isomers exhibited stronger mitogenic and PBA activities than the (S) isomers. With respect to macrophage activation such as phagocytosis, acid phosphatase and N‐acetyl‐β‐D‐glucosaminidase activity as cellular lysosomal enzymes and cytostasis, peritoneal macrophages obtained from mice admistered i.p. with test samples showed significant activities. Among stereoisomers of GLA‐27, the (R) isomer exhibited somewhat stronger phagocytic and lysosomal enzyme activities than those of the (S) isomer while there was no appreciable difference in the activities between the isomers of GLA‐40. Significant cytostasis‐inducing activity was observed in stereoisomers tested. All of the isomers showed remarkable antiviral activity against vaccinia virus.
DNA fragmentation and cytotoxicity caused by tumor necrosis factor is enhanced by interferon‐γ
Authors: Dealtry Gillian B. , Naylor M. Stuart , Fiers Walter , Balkwill Frances R. 
Published: March 2007

AbstractRecombinant human tumor necrosis factor (rhuTNF) induced DNA fragmentation in sensitive cell lines. This fragmentation was similar to that caused by lymphotoxincontaining cytotoxic T cell culture supernatants. The percentage of DNA cleaved correlated with the degree of cell growth inhibition shown by individual cell lines. DNA fragmentation was first seen after 12 h treatment, and increased slowly with time. The presence of 100 μM ZnSO4 inhibited the rhuTNF‐induced DNA cleavage in MCF‐7 cells. Recombinant interferon‐γ (rhuIFN‐γ) did not induce DNA cleavage, although it reduced the growth of all the cell lines used in this study. However, it interacted with rhuTNF to produce a doubling in the percentage of DNA fragmentation, and increased cytotoxicity in rhuTNF‐sensitive cell lines. Pretreatment with rhuIFN‐γ for 1 h prior to rhuTNF treatment also enhanced DNA fragmentation and cell killing.
Inhibition of interleukin 3 function by a fragment of the third component of complement
Authors: Faßbender Birgit , Schmitt Edgar , Bitter‐Suermann Dieter , Hadding Ulrich 
Published: March 2007

AbstractA C3d‐like (C3d‐l) fragment of 33 kDa was isolated and its biological activity studied. The fragment was generated from guinea pig C3b by porcine pancreas kallikrein and purified by fast protein liquid chromatography. The C3d‐like fragment inhibited interleukin (IL) 2‐dependent T lymphocyte proliferation. The suppressive activity of the described C3d‐l fragment was not restricted to lymphocytes as targets but inhibited in addition the proliferation of a nonlymphocyte mast cell line which was strictly IL 3‐dependent in its proliferative capacity. Kinetic studies implied early stages of cellular proliferation to be influenced. Furthermore, the C3d‐l fragment was not only an inhibitor of cellular proliferation but was also a potent inducer of leukocytosis.