bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mutation of Asp20 of human interleukin‐2 reveals a dual role of the p55 α chain of the interleukin‐2 receptor
Authors: Flemming Claudia L. , Russell Stephen J. , Collins Mary K. L. 
Published: March 2007

AbstractMutation of Asp20 in human interleukin‐2 (IL‐2) to Lys is known to result in an IL‐2 molecule with unchanged binding to the p55 subunit of the IL‐2 receptor, but with greatly decreased affinity for the p75 subunit (Collins, L., Tsien, W.‐H., Seals, C. et al. Proc. Natl. Acad. Sci USA 1988. 85: 7709). Here we demonstrate that Lys20 IL‐2 competed with a reduced (10‐fold) affinity for high‐affinity IL‐2 receptors on two murine cell lines HT2 and CTLL. In parallel with this difference in receptor interaction, Lys20 IL‐2 stimulated half‐maximal HT2 cell proliferation at a 10‐fold higher concentration than wild‐type IL‐2. However, half‐maximal stimulation of CTLL cells required a 100‐fold higher concentration of Lys20 IL‐2. A similar 100‐fold reduction in bioactivity of Lys20 IL‐2 was observed for primary, activated, human or murine lymphocytes. Anti‐p55 antibodies increased the concentration of Lys20 IL‐2 required to stimulate HT2 cells to that required for CTLL cells. These data suggest that CTLL cells, while able to bind Lys20 IL‐2 with high affinity, are lacking a p55‐dependent function necessary for optimal stimulation. Therefore, p55 has a dual role, being important both for high‐affinity IL‐2 binding and for optimal cell triggering.
Analysis of cytokine gene expression in subpopulations of freshly isolated thymocytes and thymic stromal cells using semiquantitative polymerase chain reaction
Authors: Moore Nel C. , Anderson Graham , Smith Christopher A. , Owen John J. T. , Jenkinson Eric J. 
Published: March 2007

AbstractUsing a semi‐quantitative polymerase chain reaction (PCR) technique we have examined the expression of a panel of cytokines during thymus development, localizing the expression to individual components of the thymic stroma and thymocytes at different maturational stages. The expression of interleukin (IL)‐7, stem cell factor (SCF), IL‐1α and granulocyte‐monocyte‐colony‐stimulating factor (GM‐CSF) mRNA was mapped to individual stromal cell types, while the expression of IL‐1α and GM‐CSF, along with interferon (IFN)‐γ and IL‐4 was detected in the lymphoid compartment of fetal day (Fd) 14 thymus. The expression of lymphoid‐specific cytokine genes was selectively down‐regulated in thymocytes undergoing maturation. CD3−/104+8+ cells, representing an intermediate stage of thymocyte maturation, were devoid of cytokine gene expression. Their CD3+ progeny, on the other hand, expressed IFN‐γ mRNA, supporting the notion that positive selection of cells for further maturation induces the reexpression of some cytokine genes. The cytokine profiles of the various stromal components differed. Purified major histocompatibility complex class II+ cortical epithelial cells strongly expressed IL‐7 and SCF, but only limited expression of IL‐lα and GM‐CSF could be detected. Fetal mesenchyme, on the other hand, expressed SCF, IL‐lα and GM‐CSF but not IL‐7. The importance of these cytokine profiles in relation to T cell development is discussed.
Direct evidence for anergy in T lymphocytes tolerized by oral administration of ovalbumin
Authors: Melamed Doron , Friedman Aharon 
Published: March 2007

AbstractThe present study investigated bystander suppression, specific suppression and anergy as mechanisms for oral tolerance. Oral tolerance was induced in mice by a single gastric intubation of 20 mg ovalbumin (OVA) and was evaluated in vitro by the absence of T lymphocyte proliferative responses to OVA after priming by OVA‐complete Freund's adjuvant (CFA). T lymphocyte unresponsiveness was antigen specific, systemic and was not affected by the vehicle used for immunization. T lymphocytes derived from tolerant popliteal lymph nodes (PLN) responded to an acetone precipitate (AP) of mycobacteria present in CFA; this response was not suppressed by co‐culture with OVA, thereby arguing against a mechanism of bystander suppression in our system. Responses of PLN T lymphocytes derived from OVA‐CFA primed, non‐tolerant mice, or those of an OVA‐specific T lymphocyte line, were not suppressed by PLN or spleen cells derived from OVA tolerant mice. These results excluded the possibility that oral tolerance was induced and maintained by a mechanism of specific suppression. At the cellular level, we found that OVA‐tolerant T lymphocytes did not produce interleukin‐2 (IL‐2) nor express IL‐2 receptor in response to OVA stimulation in vitro; both observations are indicative of a state of anergy. Incubation of OVA‐tolerant PLN T lymphocytes together with murine recombinant IL‐2 for 5 days, released anergic T lymphocytes and a concomitant OVA‐specific proliferative response of CD4+ T cells was detected. Taken together, our experimental system excludes the involvement of bystander or specific suppression in the induction of oral tolerance to OVA, and provides direct evidence to show that oral tolerance results from specific T lymphocyte anergy.
Expression of a 32‐kDa ligand for the CD40 antigen on activated human T lymphocytes
Authors: Hermann Patrice , Blanchard Dominique , de Saint‐Vis Blandine , Fossiez François , Gaillard Claude , Vanbervliet BÉAtrice , Briére Francine , Banchereau Jacques , Galizzi Jean‐Pierre 
Published: March 2007

AbstractTo identify the ligand(s) of the human CD40 antigen, a cDNA encoding the extracellular domain of the CD40 antigen was fused to a cDNA encoding the constant region (Fc) of human IgGl. The CD40‐Fc fusion protein was able to specifically bind to CD4+ and various CD8+ T cell clones activated with immobilized anti‐CD3. The 125I‐labeled CD40‐Fc fusion protein bound anti‐CD3 activated CD4+ T cell clone (MT9) with an equilibrium dissociation constant (Ka) of 10‐20 nM. The human CD40‐binding protein expressed on the cell surface of activated T lymphocytes is a monomeric protein of ≈ 32 kDa. Minor components of 29 kDa and 17 kDa were also detected. A small proportion of CD4+ and CD8+ blood mononuclear T cells activated by anti‐CD3 expressed the CD40 ligand but its detection was best observed following depletion of B cells. Addition of B cells to purified T cells abolished the binding of CD40‐Fc obtained after anti‐CD3 activation.
Active suppression induced by anti‐CD4
Authors: Hutchings Patricia R. , Cooke Anne , Dawe Kim , Waldmann Herman , Roitt Ivan M. 
Published: March 2007

AbstractTreatment with a non‐depleting monoclonal antibody to CD4 in the presence of mouse thyroglobulin (MTg) inhibits the development of murine autoimmune thyroiditis. This unresponsiveness was transferrable since such treatment generated a population of donor cells which could suppress the thyroiditis induced in lightly irradiated recipients by subsequent challenge with specific antigen. The suppression appears to be both antigen specific and antigen dependent and seems to discriminate between TH1 and TH2 helper subsets in that there is no significant effect on anti‐MTg autoantibodies after challenge.
Pathogenic autoimmunity to affinity‐purified mouse acetylcholine receptor induced without adjuvant in BALB/c mice
Authors: Jermy Andy , Beeson David , Vincent Angela 
Published: March 2007

AbstractMyasthenia gravis (MG) and experimental autoimmune myasthenia gravis (EAMG) are antibody‐mediated disorders in which anti‐acetylcholine receptor (anti‐AChR) antibodies cause loss of muscle AChR and subsequent weakness. Many species are susceptible to induction of EAMG with purified xenogeneic AChR in adjuvant, but injection of Torpedo AChR without adjuvants can also induce evidence of EAMG. To see whether pathogenic autoimmunity could be induced in mice by isolated mouse AChR we injected BALB/c mice with several doses (1 pmole; about 0.1 ug) of affinity‐purified AChR (from the BC3H1 cell line but thought to be identical with denervated mouse muscle) intraperitoneally, without adjuvant, over a period of 10‐22 weeks. Some of the mice became ill and died. High levels of serum anti‐mouse AChR, directed mainly towards the main immunogenic region, were found and, in the survivors, correlated with loss of muscle AChR. Thus BALB/c mice can mount an autoimmune response to minute amounts of mouse AChR, without the use of adjuvants, and this response is very similar to that found in MG. This novel finding has implications regarding the etiology of the human disease.
Reactive oxygen product formation after Fcγ receptor‐mediated neutrophil activation by monomeric mouse IgG2a: implications for the generation of first dose effects after OKT3 treatment
Authors: Zlabinger Gerhard J. , Rosenkranz Alexander R. , Schmaldienst Sabine , Stuhlmeier Karl , Böhmig Georg , Stöckl Johannes , Pohanka Erich , Kovarik Josef 
Published: March 2007

AbstractIn the present study, we provide evidence that IgG2a monoclonal antibody (mAb) OKT3 is able to induce reactive oxygen intermediate (ROI) formation in polymorphonuclear leukocytes (PMN) when FcγRIIIB as well as FcγRII are bound concomitantly. Inhibition of binding to either FcγR by specific mAb (3G8 or IV. 3, respectively) resulted in complete abrogation of the OKT3‐induced respiratory burst. The effect of OKT3 was independent from its specificity and thus also from its T cell‐activating property, since nonbinding IgG2a isotype controls induced similar amounts of ROI. The IgG2b mAb BMA031 as well as the respective nonbinding isotype control were only minimally effective. With regard to the potential role of PMN activation in inflammation and tissue damage, our findings offer an extended explanation for the generation of initial adverse reactions to OKT3. Thus, one might speculate that the concerted action of cytokines liberated after its administration, what may lead to margination of leukocytes, and activation of PMN via FcγR might produce first‐dose reactions to OKT3 by directing radical‐mediated damage against the endothelium.
Rat intestinal epithelial cell line IEC‐6 is activated by recombinant inferferon‐γ to inhibit replication of the coccidian Toxoplasma gondii
Authors: Dimier Isabelle H. , Bout Daniel T. 
Published: March 2007

AbstractToxoplasma gondii tachyzoites invaded and replicated in cultured rat small intestine cells of the line IEC‐6. Treatment of rat small intestine cells with murine recombinant interferon‐y resulted in a dose‐dependent inhibition of intracellular T. gondii replication. This could be of relevance as a first line defense against Toxoplasma infection.
Quantitative analysis of molecules which distinguish functional compartments within germinal centers
Authors: Hardie Deborah L. , Johnson Gerald D. , Khan Mahmood , MacLennan Ian C. M. 
Published: March 2007

AbstractFive zones in the secondary follicles of human tonsils are described, which are distinguished by the phenotype of their constituent cells. Moving from the apex to the base of the follicle the zones are termed: follicular mantle, outer zone, apical light zone, basal light zone and dark zone. The dark zone contains proliferating, CD77high, centroblasts and thin, widely spaced processes of follicular dendritic cells (FDC). The apical and basal light zones on the other hand contain a dense network of FDC which express CD21 and CD54 strongly. The FDC of the apical light zone differ from those of the basal light zone by their high expression of CD23. Centroblasts of the dark zone give rise to non‐proliferating centrocytes which move apically through the light zone (Eur. J. Immunol. 1991. 21: 2951). The centrocytes of the basal light zone are more pyroninophilic, more closely‐packed and larger than those in the apical light zone. Consequently, by conventional histology the basal light zone appears to be part of the dark zone. The nomenclature adopted, however, adheres to the convention that the dark zone is filled with proliferating centroblasts. Cells undergoing apopotosis were identified both in the dark and light zones, but more than half of these cells were located in the basal light zone. This is consistent with the concept that the progeny of cells which undergo somatic mutation in their immunoglobulin variable region genes in the dark zone migrate to the light zone where they are selected on the basis of their capacity to bind to antigen held on FDC. Cells receiving an antigen‐dependent signal survive while those that do not kill themselves by apoptosis. The outer zone does not contain CD23high cells and in this way is distinguished from the adjacent follicular mantle and apical light zone. It contains small lymphoid cells, blasts and plasmacytoid cells. Many cells of the outer zone express CDw75 strongly. The outer zone also extends as a narrow band around the dark zone. Possible roles of FDC and T cells of the light zone and outer zone in inducing centrocytes to differentiate to memory cells or plasmablasts are discussed.
Molecular cloning of porcine T cell receptor α, β, γ and δ chains using polymerase chain reaction fragments of the constant regions
Authors: Thome Margot , Saalmüller Armin , Pfaff Eberhard 
Published: March 2007

AbstractFragments of the constant regions of porcine α, β, δ and two types of γ T cell receptor (TcR) chains were obtained by reverse transcription and polymerase chain reaction (PCR). Screening of a porcine peripheral T cell cDN A library with these PCR fragments led to the isolation of porcine TcR α, β, γ and δ chain clones. Sequence analysis of these clones and the respective PCR fragments demonstrated the existence of one α, one β, three γ and one δ chain isotype. Comparisons of the deduced amino acid sequences of the constant region with other species revealed a significant homology. For two of the three identified porcine γ chain insertions of 38 and 40 amino acids were found within the hinge region. In addition, our sequence data demonstrate a high variability in the cytoplasmic Cγ domain among the three porcine TcR γ isotypes as well as between species, which might be of structural and/or functional significance. Comparison with biochemical data indicate the existence of four porcine TcR γ isotypes.
Murine anti‐mouse T cell monoclonal antibodies elicit anti‐antibodies in mice: intra‐species immunization model for estimating potential patient sensitization against humanized anti‐T cell antibodies
Authors: Kremmer Elisabeth , Mysliwietz Josef , Lederer Raimund , Thierfelder Stefan 
Published: March 2007

AbstractHumanization of immunosuppressive anti‐T cell monoclonal antibodies (mAb) raises the question as to how completely it helps to avoid formation of neutralizing anti‐antibodies (anti‐Ab) in patients. To get more information on intra‐species sensitization against anti‐T cell mAb, we produced two immunosuppressive mouse IgG2a anti‐mouse Thy‐1.2 mAb (MmT1 and MmT5) in AKR/J mice and measured the potential of MmT1 to elicit inhibitory anti‐Ab in AKR/J (H‐2k), C57BL/6 (H‐2b), congenic B10.BR (H‐2k) and DBA/2 (H‐2d) mice. After one injection once weekly for 4 weeks of 5 μg MmT1 (200 μg/kg) in C57BL/6 mice, without the use of any adjuvants, high concentrations of anti‐Ab directed against MmT1 (300 μg/ml) and MmT5 (100 μg/ml) were measured by enzyme‐linked immunosorbent assay. Similar concentrations of anti‐Ab were found in immunized DBA/2 and less in B10.BR mice. No syngeneic anti‐Ab could be produced in AKR/J. From the C57BL/6 mice, we raised anti‐MmT1+, MmT5+ idiotype (IDIO1) and anti‐MmT1+, MmT5+ allotype (ALLO1) mAb. An in vivo test system was adapted to measure the inhibitory effects of circulating poly‐ or monoclonal anti‐Ab. It revealed a reduction of in vivo depletion capacity not only of the sensitizing mAb (MmT1), but also of another anti‐Thy‐1.2 mAb (MmT5), with identical allotype but different idiotype.From this we conclude that intra‐species immunization following injection of anti‐T cell mAb can produce high titer inhibitory anti‐idiotype and anti‐allotype antibodies. Implications for hyperchimeric or fully human anti‐T cell mAb are discussed.
Early appearance and activation of natural killer cells in tumor‐infiltrating lymphoid cells during tumor development
Authors: Kurosawa Shin , Matsuzaki Goro , Harada Mamoru , Ando Takashi , Nomoto Kikuo 
Published: March 2007

AbstractWe investigated NK cell infiltration into tumor developing lesions at early stage of tumor development after intraperitoneal inoculation of 3LL lung carcinoma into syngeneic C57BL/6 mice. Natural killer (NK) cells, which were detected by anti‐NK 1.1 monoclonal antibody (mAb), remarkably increased in number in tumor‐developing lesions (peritoneal cavity) as early as day 3 after inoculation of 3LL. The tumor‐infiltrating NK cells from 3LL‐inoculated mice produced a high level of interferon‐γ by co‐culture with 3LL and showed enhanced cytotoxic activities against both NK‐sensitive (YAC‐1) and NK‐resistant (3LL and P815) tumors. Furthermore, mice depleted of NK cells by injection of anti‐NK 1.1 mAb or antiasialo GM1 antibody showed shorter survival times after intraperitoneal inoculation of 3LL when compared with control mice. These results suggest that NK cells infiltrate the tumor‐developing lesion at an early stage and may participate in the early protection against tumors through production of a high amount of interferon‐γ and enhanced cytotoxicity at tumor‐bearing sites.
Recombinant CD40 ligand stimulation of murine B cell growth and differentiation: cooperative effects of cytokines
Authors: Maliszewski Charles R. , Grabstein Kenneth , Fanslow William C. , Armitage Richard , Spriggs Melanie K. , Sato Timothy A. 
Published: March 2007

AbstractThe ligand for the B cell surface antigen CD40 was recently cloned from a murine thymoma cDNA library and shown to be expressed on activated T cells. In this study, we investigate the biological effects of murine recombinant CD40 ligand. The recombinant CD40 ligand expressed on the CV‐1/EBNA monkey fibroblast cell line directly activated resting B cell to express elevated levels of cell surface class II major histocompatibility complex and CD23 molecules. CD40 ligand also stimulated B cell proliferation, reaching maximal levels on day 2 of culture and declining thereafter. This effect was positively regulated by other cytokines, most notably interleukin (IL)‐4 and IL‐5. By itself, CD40 ligand had no effect upon immunoglobulin secretion by B cells. However, when B cells were treated with CD40 ligand plus cytokines, immunoglobulin secretion was stimulated in a cytokine‐dependent and isotype‐specific manner. IL‐4 was a potent co‐stimulator of IgE and IgG1 in the presence of CD40 ligand, and IL‐5 acted synergistically with IL‐4 in these responses as well as in IgM and IgG3 production. Taken together, the results indicate that CD40 ligand is a potent regulatory molecule for B cell growth and differentiation, and its activities are potentiated in a cytokine‐specific manner.
B cell epitope on the U1 snRNP‐C autoantigen contains a sequence similar to that of the herpes simplex virus protein
Authors: Misaki Yoshikata , Yamamoto Kazuhiko , Yanagi Kazuo , Miura Hitoshi , Ichijo Hiroko , Kato Tomohiro , Mato Takashi , Welling‐Wester Systke , Nishioka Kusuki , Ito Koji 
Published: March 2007

AbstractThe mechanism of autoantibody production in autoimmune diseases is not well understood. In the present study we performed the B cell epitope mapping of the U1 small nuclear ribonucleoprotein (snRNP)‐C, one of the target molecules of anti‐nRNP autoantibody to investigate how B cells respond to the autoantigen. After cloning and expression of a full length complementary DNA (cDNA) encoding the U1‐C protein, several truncated mutants of the cDNA were constructed and expressed in E. coli. Although a few epitopes were distributed on the whole molecule, all anti‐C protein antibody‐positive patients' sera tested recognized the region between amino acid residues 102 and 125 of the coding sequence. This universal epitope region contains an amino acid sequence similar to that of the herpes simplex virus type 1 ICP4 protein. The peptides representing each molecule were cross‐reactive to each other. In addition this region cross‐reacted to the B/B′ protein. These observations suggest that molecular mimicry might be involved in the initiation of autoantibody production, followed by cross‐reactive events between the autoantigens and by antigen‐driven mechanisms to generate more complicated autoantibody patterns against the U1 snRNP complexes.
The structure of the μ/pseudo light chain complex on human pre‐B cells is consistent with a function in signal transduction
Authors: Brouns Gaby S. , de Vries Evert , van Noesel Carel J. M. , Mason David Y. , van Lier René A. W. , Borst Jannie 
Published: March 2007

AbstractPrior to immunoglobulin (Ig) light (L) chain rearrangement, pre‐B cells can express μ heavy (H) chains at the cell surface in association with pseudo (ψ) L chains. This complex may be essential for B cell development. We have investigated the composition of the μ/ψL chain complex of a human pre‐B cell line, in view of its potential role in transmembrane signal transduction. The μ/λ. receptor of a mature B cell line was analyzed in comparison. The μ/ψL chain complex is associated with disulfide‐linked molecules that are homologous or identical to the mb‐1 and B29 proteins, known to be integral components of membrane Ig receptors on mature B cells. Both receptors contain tyrosine (Tyr) kinase activity. In the μ/λ receptor, the lyn and lck Tyr kinases could clearly be identified. The mb‐1 and B29 proteins in both μ/λ and μ/ψL chain receptors are substrates for in vitro phosphorylation on Tyr, but also on serine (Ser) and threonine (Thr) residues. The undefined μ‐associated Ser/Thr kinase also phosphorylates the sre‐related kinases in the μ/λ, receptor and a 43‐kDa μ‐associated protein that is present in both complexes. The 43‐kDa protein may be an integral part of both receptor types, or a transiently associated molecule instrumental in the signaling process. We conclude that the μ/ψL receptor on human pre‐B cells fulfills the presently known criteria to function as a signal transduction unit.
Structural motifs involved in human IgG antibody effector functions
Authors: Greenwood Judith , Clark Mike , Waldmann Herman 
Published: March 2007

AbstractA humanized IgG antibody to CAMPATH‐1 antigen (CDw52) is known to be lympholytic both in vitro and in vivo. So as to improve therapeutic potency through protein engineering strategies, we wish to define the structural motifs underlying some of the documented differences in function between human (h) IgG1 and IgG4 forms of the antibody. By the creation of heavy chain domain‐switch and intra‐domain recombinant antibodies we have established an important role for the carboxy‐terminal half of the CH2 domain in determining differential behaviour in antibody‐dependent cytotoxicity (ADCC) and in complement lysis. If this same region were necessary for the effector mechanisms that operate in vivo, then it might be possible to improve antibody effector functions by construction of novel antibodies that possess within the one molecule multiple copies of the crucial hinge‐CH2 associated structures. Although our previous work suggested that the hIgG4 CAMPATH‐1 antibody was ineffective at ADCC, we found this to be so only in some individuals. In others, IgG4, and indeed all the IgG subclasses were able to mediate ADCC. Overall, though, hIgG1 remains the best choice isotype for lytic therapy in vivo.