bluuebunny/crossref_metadata_2025_split huggingface dataset:
A humanized monovalent CD3 antibody which can activate homologous complement
Authors: Routledge Edward G. , Lloyd Irene , Gorman Scott D. , Clark Mike , Waldmann Herman 
Published: March 2007

AbstractThe rat monoclonal antibody (mAb) YTH12.5, specific for the CD3 antigen complex on human T cells has been modified in order to improve its efficacy in human therapy. With the aim of rendering it less immunogenic, it has been humanized using the method of framework grafting. During this process sequence analysis of the YTH12.5 VL gene indicated that it was of the λ subclass, however, it was markedly dissimilar from previously published rat and mouse Vλ gene sequences and may represent a new Vλ gene family. The humanization of this light chain represents the first successful reshaping of a λ light chain V region. To improve the effector function of the antibody we have created a monovalent form (1 Fab, 1 Fc) using a novel method involving the introduction of an N‐terminally truncated human IgG1 heavy chain gene into cells producing the humanized CD3 mAb. Comparison of the mono‐ and bivalent humanized mAb in a complement‐mediated cell lysis assay revealed that the monovalent antibody mediated lysis of human T cell blasts whereas the bivalent form did not. The availability of a humanized, complement‐fixing CD3 mAb may improve opportunities for human therapy, in the management of organ rejection, autoimmunity and the treatment of T cell lymphoma.
Major histocompatibility complex controls clonal proliferation of CD5+ B cells in H‐2‐congenic New Zealand mice: a model for B cell chronic lymphocytic leukemia and autoimmune disease
Authors: Okada Takashi , Takiura Fumiaki , Tokushige Katsutoshi , Nozawa Shingo , Kiyosawa Tomoharu , Nakauchi Hiromitzu , Hirose Sachiko , Shirai Toshikazu 
Published: March 2007

AbstractBy employing H‐2‐congenic NZB, NZW and (NZB x NZW)F1 mice with either the homozygous H‐2d/H‐2d, H‐2z/H‐2z or heterozygous H‐2d/H‐2z haplotype, we found that in the spleen of all the congenic strains homozygous for H‐2z, there were extremely high frequencies of CD5+ B cells. These cells eventually proliferated in an oligoclonal or even monoclonal fashion, and B cell‐chronic lymphocytic leukemia (B‐CLL) developed in some cases. Because this feature was not observed in H‐2d/H‐2d homozygotes or H‐2d/H‐2z heterozygotes, the high CD5+ B cell frequencies are apparently controlled by the homozygosity of a locus or cluster of loci closely linked to H‐2z complex of NZW strain. As the CD5+ B cell frequencies in the peritoneal cavity did not differ among the H‐2‐congenic strains, the frequencies of these cells in the peritoneal cavity and in the spleen appear to be at least in part under separate control. Flow cytometry and Southern blot analyses using an immunoglobulin gene JH probe revealed that the H‐2z/H‐2z homozygotes, there was a propagation of distinct clonal populations between the spleen and the peritoneal cavity, a finding which suggested that in the major histocompatibility complex (MHC)‐related microenvironments for CD5+ B cell propagation differ between the two compartments. All our findings taken together imply that certain different but related MHC haplotypes may predispose either to B‐CLL or to autoimmune disease, in close relatives.
Correlation of lymphocyte lipid composition membrane microviscosity and mitogen response in the aged
Authors: Huber Lukas A. , Xu Qing‐Bo , Jürgens Günther , Böck Günther , Bühler Ernst , Fred Gey K. , Schönitzer Dieter , Traill Karine N. , Wick Georg 
Published: March 2007

AbstractHealthy aged and young blood donors were investigated for the role of membrane lipid composition in the age‐related increase in membrane microviscosity and decline of mitogen responsiveness. Membrane microviscosity was shown to correlate positively with membrane cholesterol/phospholipid molar ratios, which were significantly elevated in the elderly. A positive correlation also was confirmed between lymphocyte membrane microviscosity, which was measured using the probe 1,6‐diphenyl 1,3,5‐hexatriene, and phytohemagglutinin responsiveness of cells from the same donor. Using stepwise regression statistical analysis, the variables age, cholesterol, cholesterol/total phospholipid and phosphatidyl ethanolamine/phosphatidyl choline molar ratios were all shown to have a significant positive influence on membrane microviscosity, whereas total phospholipids had a negative effect. No statistically significant difference was seen in content of any single saturated or unsaturated fatty acid between young and old donors. After pooling, however, the proportion of all unsaturated fatty acids was significantly higher in cells from the elderly as a consequence of an increase of n‐6 and n‐3 polyunsaturated fatty acids. Changes in lipid composition and physical properties of lymphocyte plasma membranes may, therefore, be responsible (at least partially) for the diminution of immune reactivity in old age.
Different types of allospecific CTL clones identified by their ability to recognize peptide loading‐defective target cells
Authors: Aosai Fumie , Öhlen Claes , Ljunggren Hans‐Gustaf , Höglund Petter , Franksson Lars , Ploegh Hidde , Townsend Alain , Kärre Kias , Stauss Hans J. 
Published: March 2007

AbstractAllospecific immune responses against the MHC of another individual are remarkably strong, due to a high number of responding T cell clones. Although it has been demonstrated that some allospecific cytotoxic T lymphocytes (CTL) recognize peptides presented by allogeneic MHC class I molecules, it has remained unclear whether MHC molecules can be recognized directly. We used the H‐2b‐derived murine lymphoma mutant RMA‐S, which has a defect affecting peptide loading of class I molecules, to test whether recognition by allospecific CTL always requires the presence of peptides. Three types of anti‐H‐2Kb CTL clones can be distinguished by their ability to lyse RMA‐S target cells. Type A CTL clones efficiently lyse these target cells, the lysis by type B CTL clones is inefficient, and type C clones fail to lyse RMA‐S. Up‐regulation of the levels of H‐2Kb density improved lysis by type B clones, but did not lead to lysis by type C clones. Some type A and B CTL clones apparently can recognize class I molecules devoid of peptides, while others are likely to recognize peptides which are not affected by the presentation defect of RMA‐S. We suggest that type C clones are specific for peptides which are not presented by the mutant cells. The results show that the majority of alloreactive CTL recognize peptide/MHC complexes, while some CTL behave as if they can recognize class I molecules in the absence of MHC‐bound peptides.
Cloning, heterologous expression and characterization of murine interleukin 1 receptor antagonist protein
Authors: Shuck Mary E. , Eessalu Thomas E. , Tracey Daniel E. , Bienkowski Michael J. 
Published: March 2007

AbstractA cDNA coding for the human interleukin 1 receptor antagonist protein (IL 1Ra) was used to clone the corresponding murine cDNA. The nucleotide sequence of the open reading frame coding for the processed form of mIL 1Ra predicted a 152‐residue protein that was 77% identical to human IL 1Ra. The cellular and tissue distribution of murine IL 1Ra (mIL 1Ra) transcripts showed high levels in macrophages and skin while lower levels were detected in tissues that contain significant numbers of resident macrophages. The portion of the mIL 1Ra cDNA that codes for the mature form of the protein was placed under the control of a Trp promoter and expressed in E. coli at a level of 37% of total cell protein. The expressed protein was secreted into the periplasm and was purified to homogeneity in a single step by cation‐exchange chromatography. Recombinant mIL 1Ra competitively inhibited 125I‐labeled IL 1α binding to murine type I IL 1R present on EL4 6.1 cells (Ki value of 0.21 nM) and antagonized IL 1‐stimulated co‐mitogenesis in murine thymocytes (0.7 x 106‐1.1 x 106 units/mg).
Evidence for multiple sites of interaction in C3 for complement receptor type 2 (C3d/EBV receptor, CD21)
Authors: Esparza Inmaculada , David Becherer J. , Alsenz Jochem , De La Hera Antonio , Lao Zhege , Tsoukas Constantine D. , Lambris John D. 
Published: March 2007

AbstractMultivalent but not monovalent CR2 ligands are required to elicit Raji cell proliferation as well as other B cell responses. It has been reported (C. Servis and J. D. Lambris, J. Immunol. 1989. 142: 2207) that the tetrameric peptide T‐(C31202–1214)4, which represents the CR2‐binding site in C3d, was able to support Raji cell growth. We show here that the tetrameric peptide T‐(gp35019–30)4, which contains the CR2‐binding site in gp350 protein of EBV also induces Raji cell growth and this effect is inhibited by the monomeric peptides gp35019–30 and C31201–1214. We also investigated the nature of the interaction between C3 fragment and CR2 in order to explain the Raji cell growth‐supporting effect exerted by C3. The following findings suggest that there are multiple sites in the C3 molecule able to interact with CR2: (1) both C3c and C3d immobilized on microspheres are able to bind to Raji cells through CR2.(2) soluble C3d inhibits to a greater extent the binding of CR2 to fixed C3d than to fixed C3b, which suggests the existence of additional CR2‐binding sites within C3b not present in the C3d portion of the molecule; (3) synthetic peptides C31187–1214, C3741–757 and C3295–307 which represent regions of similarity in the C3 molecule bind specifically to CR2 on Raji cells and compete with each other for binding to the receptor and (4) preincubation of microtiter plate‐fixed C3b with monoclonal or polyclonal anti‐peptide antibodies (C3‐9, anti‐C3727–768) recognize the N terminus of the α chain of C3 (including residues 741‐757) inhibited CR2 binding. Therefore, these data suggest that the N terminus of the α chain of C3 is involved in binding to CR2.
Minor histocompatibility antigens, defined by graft‐vs.‐host disease‐derived cytotoxic T lymphocytes, show variable expression on human skin cells
Authors: De Bueger Marleen , Bakker Astrid , Van Rood Jon J. , Goulmy Els 
Published: March 2007

AbstractLittle is known on the effector mechanisms inducing the cutaneous lesions observed during acute graft‐vs.‐host disease (aGvHD) after allogeneic bone marrow transplantation (BMT). Histological findings have indicated that infiltrating CD8+ lymphocytes probably play a role. We addressed the question of whether host minor histocompatibility (mH) antigen‐reactive cytotoxic T lymphocytes (CTL) could account for this phenomenon via direct lysis of the epidermal cell layer. Six CTL clones, obtained from peripheral blood lymphocytes of patients suffering from aGvHD, each recognizing a well‐characterized MHC class I‐restricted mH antigen epitope, were tested on cultured keratinocytes of nine MHC and mH antigen‐typed donors. Four of six mH antigen‐specific CTL clones lysed unstimulated MHC class I‐expressing, as well as recombinant interferon‐γ (rlFN‐γ)‐activated, ICAM‐1, MHC class I‐ and II‐expressing keratinocytes. Two strongly cytolytic CTL clones showed no recognition of keratinocytes of donors whose phytohemagglutinin‐activated T cell lines were readily lysed. With respect to aGvHD, the results imply that some class I‐restricted CTL obtained from peripheral blood lymphocytes of aGvHD patients have the in vitro potential to destroy resting as well as IFN‐γ‐activated epidermal cells, whereas others do not. In other words, CTL‐defined human mH antigens vary with respect to their expression in the skin. It is intriguing that those minor H antigens which cannot be detected on human keratinocytes in vitro are those known to be associated with the occurrence of GvHD.
Signaling by vascular cell adhesion molecule‐1 (VCAM‐1) through VLA‐4 promotes CD3‐dependent T cell proliferation
Authors: Burkly Linda C. , Jakubowski Aniela , Newman Barbara M. , Rosa Margaret D. , Chi‐Rosso Gloria , Lobb Roy R. 
Published: March 2007

AbstractVascular cell adhesion molecule, VCAM‐1, is an adhesion molecule expressed on activated endothelium thought to play a role in leukocyte migration to sites of inflammation. VCAM‐1 adheres to leukocytes through the VLA‐4 integrin. Recombinant soluble VCAM‐1 (rsVCAM) and anti‐CD3 mAb OKT3 were utilized to address the role of the VCAM‐1/VLA‐4 pathway in antigen‐dependent T cell activation. Monocyte‐depleted T cells proliferated upon exposure to co‐immobilized OKT3 and rsVCAM but to neither alone. In contrast, an anti‐VLA‐4 mAb HP1/2 failed to co‐activate with OKT3, despite the fact that both rsVCAM and HP1/2 support T cell adhesion comparably. These data indicate that adhesive function is not sufficient for co‐stimulatory activity. They also reveal that VCAM‐1 may play a role in regulating T cell immune responses as well as migration in vivo.
Limiting dilution analysis of proliferative T cell responses to mycobacterial 65‐kDa heat‐shock protein fails to show significant frequency differences between synovial fluid and peripheral blood of patients with rheumatoid arthritis
Authors: Fischer Heinrich Peter , Sharrock Claire E. M. , Colston M. J. , Panayi Gabriel S. 
Published: March 2007

AbstractRecent evidence has pointed to the mycobacterial 65‐kDa heat‐shock protein (hsp 65) as an antigen that may be important in the pathogenesis of rheumatoid arthritis (RA). Using limiting dilution analysis the frequency of purified protein derivative of tuberculin (PPD) and hsp 65‐responsive T cells was measured in paired peripheral blood and synovial fluid samples of patients with RA. There was no increase in the anti‐PPD or anti‐hsp 65 frequency in synovial fluid compared with peripheral blood. In addition, no difference was found between peripheral blood of RA patients and healthy controls. These results do not support the idea of an important pathogenic role of T cells responding to hsp 65, or a cross‐reacting antigen, in RA.
In vivo evaluation of the effects of interleukins 2, 4 and 7 on enhancing the immunotherapeutic efficacy of anti‐tumor cytotoxic T lymphocytes
Authors: Lynch David H. , Namen Anthony E. , Miller Robert E. 
Published: March 2007

AbstractThe draining lymph nodes of mice injected with viable syngeneic tumor cells contain lymphoid cells capable of generating anti‐tumor cytotoxic T lymphocytes (CTL) during a 4‐day in vitro culture period and intravenous infusion of relatively low numbers of these CTL can effectively eliminate a challenge of fibrosarcoma cells at distal skin sites that would otherwise result in the death of the host. Using this model system the effects of addition of interleukin (IL)2, IL4 or IL7 to the culture medium on the therapeutic efficacy of the anti‐tumor CTL generated was investigated. In this regard, IL7 was found to be the most potent of the cytokines tested. Addition of IL7 either alone, or in combination with low doses of IL2, resulted in the generation of CTL with significantly (6–8‐fold) enhanced therapeutic efficacy in vivo. Anti‐tumor effector cells generated in the presence of IL7 were also found to be at least 4‐fold more effective at eliminating established tumors than CTL generated in medium alone. Of the other cytokines tested, addition of IL2 resulted in elevated CTL activity in vitro, but only a modest (approximately 2–3‐fold) enhancement of the therapeutic efficacy in vivo. Addition of IL4, either alone or in combination with IL2, also resulted in the generation of effector cells with enhanced tumoricidal activity in vitro and yet the therapeutic efficacy of these cells was decreased compared to that of CTL generated in medium alone. These observations indicate that (a) inclusion of IL 7 in the medium in which tumor‐reactive T cells are cultured can markedly enhance the immunotherapeutic efficacy of the resulting effector cell populations; and (b) in vitro assays of tumoricidal activity cannot be used as a reliable predictor of therapeutic efficacy in vivo.
Functionally distinct subsets of human γ/δ T cells
Authors: Morita Craig T. , Verma Sunita , Aparicio Pedro , Martinez‐A. Carlos , Spits Hergen , Brenner Michael B. 
Published: March 2007

AbstractTo determine if effector subsets exist among human γ/δ T cells, we examined the cytokine production and cytotoxic activity of γ/δ T cell clones with different accessory molecule phenotypes, Vδ and Vγ gene expression, and Jγ rearrangements. T cell clones bearing γ/δ T cell receptor produce an array of cytokines like α/β T cell clones. Individual γ/δ T cell clones produced a characteristic array of cytokines without correlation with Vδ or Vγ gene expression. However, when phenotypic subsets were considered, CD4+ γ/δ clones produced significantly higher levels of interleukin 2 and granulocyte‐monocyte colony‐stimulating factor compared with CD4−CD8− and CD8+ γ/δ clones. Similarly, when cytotoxic potential was assessed, CD4+ γ/δ clones exhibited minimal activity when compared with CD4−CD8− and CD8+ adult peripheral blood γ/δ clones. We conclude that functionally distinct γ/δ T cell subsets exist and suggest that these subsets may correlate with expression of the CD4 accessory molecule.
A strong propensity toward loop formation characterizes the expressed reading frames of the D segments at the Ig H and T cell receptor loci
Authors: Abergel Chantal , Claverie Jean‐Michel 
Published: March 2007

AbstractA compilation of murine and human Ig H and TcR β D segment sequences was used to estimate the relative usage of the various reading frames and to look for associated sequence patterns. We confirm a strong bias in the expression of the Ig H D segments, with more than 90% (murine) and 85% (human) expressed peptides resulting from a preferred reading frame. Remarkably, 86% (mouse) and 90% (human) of those peptides contain at least one glycine residue. All but one of the atypical preferred D peptides contain serine or proline residues and are found in the immediate vicinity of glycine residues provided by specific JH segments. The presence of tyrosine residues is also a characteristic feature of expressed reading frames in both mouse (75%) and human (90%). These results suggest that the constraints of forming a flexible loop within the third complementarity‐determining region, is a factor in the preference for a particular reading frame in Ig H D. For the TcR β D segments, glycine is specified in most reading frames, and no significant preference is observed.
T lymphocyte adhesion to the fibronectin and laminin components of the extracellular matrix is regulated by the CD4 molecule
Authors: Hershkoviz Rami , Miron Shmuel , Cohen Iran R. , Miller Ariel , Lider Ofer 
Published: March 2007

AbstractThe adhesion of T cells to components of the extracellular matrix (ECM) is mediated by the β1 subfamily of integrin receptors, designated VLA. It has been recently demonstrated that the binding of VLA receptors to protein components of the ECM is rapidly augmented by the activation of the T cells without, however, any actual change in the level of expression of the VLA receptors for fibronectin (FN) or laminin (LN). Thus, it is likely that activation of existing VLA receptors is required for binding. The activation must be regulated by T cell surface molecules capable of transducing signals into the cell. We studied the role of the CD4 molecule in the binding of rat CD4+ T cells to the FN and LN components of the ECM. We now report that the CD4 molecule appears to play a major role in regulating T cell interactions with ECM. This conclusion is based on the following observations: (a) monoclonal antibodies directed against the CD4 molecule inhibited T cell adhesion to both FN and LN; (b) down‐regulation of the CD4 molecule resulted in partial loss of the ability of CD4+ T cells to adhere to FN and LN; (c) a CD4+ T cell clone adhered to both FN and LN while a CD4−CD8− clone expressing an identical T cell receptor bound weakly to both proteins and (d) treatment of the CD4+ T cells with an inhibitor of the CD4‐associated tyrosine protein kinase activity inhibited T cell adhesion to both ECM proteins.
Pre‐B lymphocyte‐specific transcriptional control of the mouse VpreB gene
Authors: Okabe Taijiro , Bauer Steven R. , Kudo Akira 
Published: March 2007

AbstractThe VpreB genes, which encode surrogate immunoglobulin light chain molecules, are expressed as RNA almost exclusively in pre‐B cells. We have investigated the transcriptional control mechanisms which are responsible for the pre‐B cell‐specific RNA expression of the mouse VpreB1 and VpreB2 genes. Nuclear run‐on analyses demonstrate that the pre‐B cell‐specific expression of both VpreB genes is controlled primarily at the level of initiation of transcription. S1 nuclease protection‐mapping defined two or three major start sites of transcription for the VpreB genes. To find a promoter and other potential cis‐acting regulatory elements, a 700‐bp fragment 5′ of the transcription start sites of the VpreB1 gene was used in gene transfer experiments and found to act as a promoter in pre‐B lymphocytes. Deletion experiments showed that 191 bp upstream of the most 5′ transcription start site is required for the pre‐B cell promoter activity. DNA sequence analysis of the 5′ region of the mouse VpreB1, VpreB2 and human VpreB genes reveal that this region of approximately 200 bp is strongly conserved. This 200‐bp promoter region contains several conserved nucleotide sequence motifs which may act to mediate the pre‐B cell‐specific transcription of the VpreB genes.
A pre‐B‐ and B cell‐specific DNA‐binding protein, EBB‐1, which binds to the promoter of the VpreB1 gene
Authors: Okabe Taijiro , Watanabe Takeshi , Kudo Akira 
Published: March 2007

AbstractThe VpreB1 protein is thought to be expressed on the surface of pre‐B cells in association with λ5 and μ, heavy chain, and to play an important role on B cell differentiation. The expression of VpreB1 and λ5 is pre‐B cell specific, and regulated at the initiation of transcription. We have identified at least two sequence‐specific DNA‐binding proteins which bind to the region −191 to ‐74 of the promoter of the mouse VpreB1 gene. These DNA‐binding proteins also bind to the promoter of the mouse λ5 gene. One of the two DNA‐binding proteins, called EBB‐1, is restricted to pre‐B and B cells, but not detected in plasma cells, T cells and cells of other lineages. Transient transfection analysis of reporter constructs revealed that the binding sites of these proteins play a significant role in the activity of the promoter, especially the binding site of EBB‐1. Taken together these results suggest that EBB‐1 might be one of the crucial factors which regulates a series of intracellular events in B cell differentiation.
Regulation of D‐3 phosphoinositides during T cell activation via the T cell antigen receptor/CD3 complex and CD2 antigens
Authors: Ward Stephen G. , Ley Steven C. , Macphee Colin , Cantrell Doreen A. 
Published: March 2007

AbstractAn immediate consequence of T cell activation via the T cell receptor (TcR)/CD3 complex and CD2 antigen is the hydrolysis of phosphatidylinositol‐(4,5)‐bisphosphate and the generation of inositol‐(1,4,5)‐trisphosphate and diacylglycerol which then regulate intracellular calcium and protein kinase C. Changes in cellular levels of phosphoinositides phosphorylated on the D‐4 and D‐5 position during T cell activation have been well documented. Recently it has been proposed that phosphoinositides phosphorylated on the D‐3 position of the inositol ring by a novel phosphoinositide (PI) 3 kinase may also be important in cell activation. In the present study we have examined the levels and regulation of D‐3 phosphoinositides in T cells activated by the TcR/CD3 complex and CD2 antigens. The data show the existence of phosphatidylinositol‐(3)‐monophosphate [PtdIns(3)P], phosphatidylinositol‐(3,4)‐bisphosphate [PtdIns(3,4)P2] and phosphatidylinositol‐(3,4,5)‐trisphosphate [PtdIns(3,4,5)P3] in T cells. Activation of the TcR/CD3 complex or CD2 antigen results in modulation of PtdIns(3,4)P2 and a putative PtdIns(3,4,5)P3 in T cells but does not change levels of PtdIns(3)P. These data provide the first evidence that lipid products of a PI 3 kinase exist in T cells.