bluuebunny/crossref_metadata_2025_split huggingface dataset:
B cell repertoire in adult antigen‐free and conventional neonatal balb/c mice
Authors: Bos Nicolaas A. , Meeuwsen Cornelia G. , Wijngaarden Peter Van , Benner Robbert 
Published: March 2007

AbstractHybridomas were derived from lipopolysaccharide‐reactive splenic B cells of adult germ‐free BALB/c mice fed a chemically defined ultrafiltered “antigen‐free” diet (GF‐CD) and from splenic B cells of 5‐day‐old conventional (CV‐NEO) BALB/c mice. The monoclonal antibodies (mAb) from both collections of hybridomas were tested for reactivity against a large panel of antigens of exogenous and endogenous origin. As a source of natural exogenous antigens 36 different bacteria and 9 different viruses were used, while as endogenous antigens frozen tissue sections of stomach, liver and kidney, the Hep‐2 cell line and the anti‐idiotopic mAb Ac38 and Ac146 were used. In both collections of mAb approximately 70% reacted with one or more bacterial antigens, while no reactivity could be detected against the viral antigens. Of the GF‐CD and CV‐NEO hybridomas, 16% and 19%, respectively, reacted with one or more frozen tissue sections. Overall 56% and 68% of the GF‐CD and CV‐NEO hybridomas, respectively, were producing multireactive antibodies reactive to several exogenous and/or endogenous antigens.Among the GF‐CD hybridomas a correlation was found between multireactivity and the usage of the VH gene family PC7183. In CV‐NEO hybridomas, however, the preferential utilization of the VH gene family PC7183 was found among both mono‐and multireactive hybridomas. The results suggest (a) that the actual B cell repertoire of neonatal mice consists of a large proportion of multireactive B cells which are reactive with autoantigens and bacterial antigens, but not viral antigens and (b) that in antigen‐deprived mice the neonatal repertoire is largely preserved during maturation of the mice.
Detection of soluble class i molecules (non hla‐a or hla‐b) in serum, spleen membranes and lymphocytes in culture
Authors: Villar Luisa M. , Roy Garbine , Lázaro Iciar , Álvarez‐Cermeno José C. , González Miguel , Brieva José A. , Del La Sen María L. , Leoro Galo , Bootello Alfredo , González‐Porqué Pedro 
Published: March 2007

AbstractSoluble major histocompatibility complex class I molecules (sHLA) present in human serum can be resolved by gel filtration into two different peaks with an apparent molecular mass of about 200 kDa (30% of the total) and 50–60 kDa (60%–70%). The serological analysis of the peaks shows that A or B specificities can only be detected in the 200 kDa peak while both are recognized by the monomorphic W6/32 monoclonal antibody (mAb) and anti‐β2‐microglobulin mAb. Such sHLA (non HLA‐A or ‐B) molecules are released from human spleen membranes upon incubation at 37 °C and have been purified by affinity chromatography with mAb W6/32 bound to Sepharose. The molecular mass analysis by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis of the sHLA (non HLA‐A or ‐B) and of the classical HLA‐A or ‐B antigens still bound to the membranes and purified from the same membranes after detergent solubilization does not show a significant difference, indicating that sHLA do not represent proteolytic fragments of the classical HLA‐A or ‐B antigens. The presence of sHLA (non HLA‐A or ‐B) has also been detected in the supernatants of lymphocyte cultures and increases dramatically upon stimulation by mitogens. The effect of pokeweed mitogen, phytohemagglutinin, Staphylococcus aureus Cowan strain and phorbol 12‐myristate 13‐acetate on the secretion of sHLA has been studied. The molecular mass of the secreted sHLA (detected using [14C]leucine) is compared with the classical transmembrane proteins.
Only dfl16, dsp2, and dq52 gene families exist in mouse immunoglobulin heavy chain diversity gene loci, of which dfl16 and dsp2 originate from the same primordial dh gene
Authors: Ichihara Yoshikazu , Hayashida Hidenori , Miyazawa Sanzo , Kurosawa Yoshikazu 
Published: March 2007

AbstractIn mice, 12 germ‐line DH genes belonging to three different families (DQ52, DSP2 and DFL16) have been identified. The DH genes other than DQ52 are clustered in the 60 kb‐long region located between VH and JH genes. Since there are seven DH gene families (DHQ52, DXP, DA, DK, DN, DM and DLR) in humans, we tried to identify new DH gene families in the 60 kb‐long region using human DH gene probes. Mouse and human DH genes showing the highest similarity were mouse DFL16 genes and human DA genes. Southern hybridization of the mouse clones covering the 60‐kb region with human DH probes did not detect any other DH genes. Nucleotide sequence analysis of the 4.0‐kb fragment containing the DFL16.1 gene confirmed this conclusion. Comparison of the 12 germ‐line DH genes and more than 150 somatic DH sequences also indicated that there are not more germ‐line DH genes in the mouse genome. Moreover, comparison of nucleotide sequences of DFL16.1 and DSP2.2 genes and their surrounding regions suggests that both DH gene families originate from the same primordial DH gene. Using the flanking sequences of both DH genes, the divergence date between DFL16 and DSP2 genes was estimated at around 37 million years ago.
Allo‐class i‐reactive cd4‐cd8‐ t cell hybridomas recognize the conformational change of class i molecule resulting from the exchange of the α3 domain
Authors: Yamamoto Junji , Tanabe Manabu , Minami Mutsuhiko , Kano Kyoichi , Takiguchi Masafumi 
Published: March 2007

AbstractH‐2Kb‐reactive, interleukin (IL) 2‐producing T cell hybridomas possessing neither CD8 nor CD4 molecules were employed for the study of allorecognition on interspecies hybrid antigens by T cells in the absence of an influence of these accessory molecules. Both HTB176.10 and HTB177.2 T cell hybridomas reacted with KbKbB7 hybrid antigens as well as Kb antigens and they produced more IL2 in response to Kb antigens than KbKbB7 hybrid antigens. IL2 production of these T cell hybridomas was dependent on the surface expression level of Kb molecules on stimulators. Therefore, L cells expressing almost equivalent levels of Kb or hybrid antigens were selected for further functional studies by these T cell hybridomas. They apparently produced less IL2 in response not only to interspecies hybrid antigens but also to interspecies hybrid antigens in response to Kb antigens. These results indicated that T cell hybridomas recognized the conformational change of class I molecule resulting from the exchange of the α3 domain via their T cell receptors.
Presentation of igg2a antigens to class ii‐restricted t cells by stably transfected b lymphoma cells
Authors: Bikoff Elizabeth K. , Eckhardt Laurel A. 
Published: March 2007

AbstractHere we describe a panel of BALB/c T cells specific for IgG2a of the b allotype in association with I‐Ad. We used DNA‐mediated gene transfer techniques to localize antigenic determinants recognized by responding T cells. Initially a truncated IgG2aa gene comprising a variable domain and the CH3 domain (not including the membrane exons) from the BALB/c IgG2aa heavy chain was introduced into myeloma cells. The V‐CH3 protein was expressed at high levels under control of the Ig heavy chain enhancer. Secretion of the V‐CH3 protein did not require assembly of H‐H dimers or an association with light chains.To generate stably transfected B cell lines that would stimulate our class II‐restricted T cells, we replaced most of the BALB/c IgG2aa CH3 exon with CH3 coding sequences from a C57BL/6 IgG2ab cDNA clone and introduced these constructs into Ia+ B lymphoma cells. The IgG2ab CH3‐transfected B cells were recognized by BALB/c Igh‐1b‐specific T cell hybrids in the absence of exogenous antigen. Experiments using glutaraldehyde‐fixed cells as stimulators indicate that presentation of the secreted form of V‐IgG2ab CH3 requires processing. We found that a significant fraction of the endogenously synthesized V‐IgG2ab CH3 protein was, however, present as already processed antigen.
A new cell surface molecule closely related to mouse class i transplantation antigens
Authors: Cochet Madeleine , Casrouge Armanda , Dumont Anne‐Marie , Transy Catherine , Baleux FrançOise , Maloy W. Lee , Coligan John E. , Cazenave Pierre‐André , Kourilsky Philippe 
Published: March 2007

AbstractThe “37” H‐2 class I mouse gene, located in the Tla complex, is poorly polymorphic and is transcribed in a wide variety of cells and tissues. Using antisera directed against peptides deduced from the gene sequence, we demonstrate that the 37 gene encodes a 45.5‐kDa cell surface glycoprotein. This protein, initially identified on the surface of mouse L cells transfected with an overexpressing 37 gene, is present on cells such as splenocytes of various mouse strains except those of A/J mice. Thus, mouse cells may express not only the major transplantation antigens encoded by the K and D region genes, but at least one additional poorly polymorphic class I molecule encoded by the 37 gene.
Camp inhibits the okt3‐ induced increase in cytoplasmic free calcium in the jurkat t cell line: the degree of inhibition correlates inversely with the amount of cd3 binding ligand used*
Authors: Papadogiannakis Nikos , Nordström Tommy E. , Andersson Leif C. , Wolff C. Henrik J. 
Published: March 2007

AbstractWe have investigated the effect of cAMP concentration on the CD3‐mediated rise in intracellular Ca2+ induced by anti‐CD3 monoclonal antibody in the human T cell leukemia line Jurkat. Forskolin, prostaglandin E2 (PGE2) and dibutyryl cAMP (db‐cAMP) were used to increase intracellular cAMP concentrations. Treatment of Jurkat cells with forskolin or db‐cAMP for 3 h inhibited the subsequent rise in intracellular Ca2+ concentration induced by an optimally mitogenic dose of 100 ng/ml of the anti‐CD3 OKT3, whereas PGE2 counteracted the Ca2+ rise only marginally. The inhibitory effect of forskolin and PGE2 on the Ca2+ signal correlated with their abilities to induce increased cAMP levels in Jurkat cells. The suppression of the Ca2+ response was dependent on the concentration of the cAMP‐elevating agent and the time of pre‐incubation with the drug. The cAMP‐mediated inhibition of the Ca2+ response diminished or disappeared when increasing concentrations of OKT3 were used to stimulate the rise in intracellular Ca2+ concentration. The results indicate that cAMP participates in the regulation of T lymphocyte activation at the level of signal transduction. Our findings, which stress the crucial role of the concentration of the ligand used to trigger Ca2+ responses, provide an explanation to previous contradictory reports on the impact of cAMP on the signal transduction in T cells.
Sequence and linkage of the vχ21a and g germ‐line gene segments in the mouse
Authors: Alanen Anna , Weiss Siegfried 
Published: March 2007

AbstractThe germ‐line V gene segments encoding the subgroups A and G of the BALB/c Vχ21 family were cloned and assigned to the previously described 30‐kb cluster of the Vχ21 family. Sequence comparison revealed close homology between the two gene segments at the DNA and the predicted amino acid sequence level, indicating that Vχ21A and Vχ21G originated by a rather recent gene duplication.
Establishment of an anti‐A human monoclonal antibody from a blood group A lung cancer patient: evidence for the occurrence of autoimmune response to difucosylated type‐2 chain A
Authors: Inoue Hiroshi , Hirohashi Setsuo , Shimosato Yukio , Enjoji Munetomo , Clausen Henrik , Hakomori Sen‐Itiroh 
Published: March 2007

AbstractA human monoclonal antibody, NCC‐HAL‐27, has been established by a combination of transformation by Epstein‐Barr virus (EBV) and a newly devised “micro cell fusion” technique. Lymphocytes used were derived from a blood group A lung cancer patient. Cancer cells, as well as normal epithelial cells of lung, stomach and colon (including autologous tissue) from blood group A individuals, fixed in formalin, were immunohistochemically stained by the antibody. A higher concentration (> 140 mg/ml) of the antibody agglutinated only type‐A (not B or 0) erythrocytes. The structural specificity of NCC‐HAL‐27 was determined by particle‐concentrated fluorescence immunoassay and thinlayer chromatography immunostaining using purified, well‐defined glycolipids. The antibody was found to be directed against type‐2 chain A and difucosylated type‐2 chain A antigens with no cross‐reactivity with known A‐like antigens, such as Tn and Forssman antigen, generally expressed irrespective of ABO status. Interestingly, however, the antibody detected the expression of incompatible A antigen in colon cancers of B and 0 individuals with high incidence (30%‐40%). The finding that a monoclonal antibody generated from a blood group A cancer‐bearing host is directed against autologous A antigen is novel because the AB0 blood group antigens are the major alloantigens in man, with strictly controlled immunotolerance. The induction of anti‐A in this patient could, therefore, be directly associated with the lung cancer.
Disparate functions of I‐A and I‐E molecules on B cells as evidenced by the inhibition with anti‐I‐A and anti‐I‐E antibodies of polyclonal B cell activation
Authors: Takahama Yousuke , Ono Shiro , Ishihara Katsuhiko , Muramatsu Minoru , Hamaoka Toshiyuki 
Published: March 2007

AbstractPolyclonal differentiation of unprimed B cells into IgM‐producing cells induced by lipopolysaccharide (LPS) or T cell‐derived lymphokine B151‐TRF2 has been shown to contain a process of I‐A‐restricted B‐B cell interaction, so that the B cell responses are inhibited by monoclonal antibodies (mAb) specific for I‐A molecules. On the other hand, the B cell responses are also inhibited by anti‐I‐E mAb, although I‐E molecules are not involved in such B‐B cell interaction. In this study, we examined the mechanism underlying the anti‐I‐E‐mediated inhibition of the B cell responses. The B cell responses induced by LPS or B151‐TRF2 were inhibited by either anti‐I‐A or anti‐I‐E mAb added on day 0 over a 5‐day culture period, whereas when added on day 3 the responses were inhibited only by anti‐I‐E mAb and not by anti‐I‐A mAb. To gain insight into the mechanism underlying the anti‐I‐E‐mediated inhibition, we prepared monovalent Fab and divalent F(ab')2 fragments of anti‐I‐A and anti‐I‐E mAb and examined their effects on the B cell responses. We found that the B cell responses were inhibited by the F(ab')2 but not Fab fragment of anti‐I‐E mAb, whereas the Fab fragment of anti‐I‐A mAb still gave effective inhibition. The F(ab')2 but not Fab fragment of anti‐I‐E mAb induced increases in cyclic AMP (cAMP) levels in B cells, whereas the undigested anti‐I‐A mAb did not induce such increases. Furthermore, adenylate cyclase inhibitors, which inhibit cellular cAMP accumulation, circumvented the B cell responses inhibited by anti‐I‐E but not anti‐I‐A mAb. Thus, these results indicate that the anti‐I‐E‐mediated inhibition of the B cell responses requires increases in intracellular cAMP levels induced by cross‐linking of I‐E molecules. In contrast, anti‐I‐A mAb inhibits the B cell responses without cross‐linking of I‐A molecules and cAMP accumulation. These results reinforce a unique function of I‐A molecules as restriction elements in the Ia‐restricted B‐B cell interaction.
Derivation of a T cell hybridoma variant deprived of functional T cell receptor α and β chain transcripts reveals a nonfunctional α‐mRNA of BW5147 origin
Authors: Letourneur FranÇOis , Malissen Bernard 
Published: March 2007

AbstractWe have isolated a variant of the DO‐11.10.7 mouse T cell hybridoma which does not express functional T cell receptor α/β chains. This variant, denoted 58 α−β−, can be used as a recipient for T cell receptor α/β gene transfer experiments to obtain cell lines which express only the products of the transfected α/β genes at their surfaces. In the process of characterizing the defects affecting the 58 α−β− T cell receptor genes, we have found that the parental BW5147 thymoma has undergone a previously unnoticed Vα‐Jα rearrangement. This α rearrangement involves a Vα pseudogene segment and accounts for the high level of α‐mRNA transcripts present in the BW5147 α−β− variant. Knowledge of the existence of this second, albeit nonfunctional, α‐mRNA in BW5147 is of importance, since it could be, and actually already has been, mistakenly identified (due to partial nucleotide sequencing) in T hybrids as a functionally significant message donated by the normal T cell parent.
Surface expression of CD3 in the absence of T cell receptor (TcR): evidence for sorting of partial TcR/CD3 complexes in a post‐endoplasmic reticulum compartment
Authors: Ley Steven C. , Tan Kut‐Nie , Kubo Ralph , Sy Man‐Sun , Terhorst Cox 
Published: March 2007

AbstractThe T cell receptor (TcR) for antigen, on the majority of T cells, is a disulfide‐linked heterodimer composed of the α and β chains, noncovalently associated with the CD3 complex of polypeptides (γ, δ, ϵ and ζ). In this report, two murine thymoma cell lines are described which synthesized incomplete TcR/CD3 complexes and expressed low levels of CD3 on their surface in the absence of the TcR chains. The partial TcR/CD3 complexes were composed primarily of the inherently metabolically stable CD3 γ and ϵ subunits. These results were in contrast to previous studies, which suggested that synthesis of all of the component chains of the TcR/CD3 complex is required for the successful transport of any of the chains to the cell surface. The efficiency of transport of the partial TcR/CD3 complexes from the endoplasmic reticulum (ER) to medial Golgi in the two thymomas was similar to complete complexes. However, the transport of the incomplete receptors was impaired at some point between the medial Golgi and the plasma membrane. Taken together with previous studies, these results suggested that T cells have mechanisms to retain partial TcR/CD3 complexes intracellularly both in the ER and in an undefined post‐ER compartment. However, the transport of low levels of partial TcR/CD3 complexes to the cell surface in some T cell lines implied that the retention mechanisms may not always be completely efficient. Cross‐linking of the surface, partial TcR/CD3 complexes with anti‐CD3 ϵ antibodies did not stimulate interleukin 2 (IL 2) production. It is possible, however, that the partial TcR/CD3 complexes have some function which is unrelated to the stimulation of IL 2 production.
Induction of class II major histocompatibility complex antigens in murine placenta by 5‐azacytidine and interferon‐γ involves different cell populations
Authors: Athanassakis‐Vassiliadis Irene , Thanos Dimitris , Papamatheakis Joseph 
Published: March 2007

AbstractClass II MHC antigen expression is required for recognition of an alloantigen and generation of immune response. In rodents as well as in humans primary trophoblasts do not express class II MHC antigens. In this study we focused our interest on the mechanism(s) of class II antigen suppression on murine trophoblasts. First, we examined the possibility of gene inactivation by methylation and second the possibility of lymphokine regulation of the class II genes. The first possibility was tested by treatment of placental cells with 5‐azacytidine (5‐AzaC), a cytidine analog which upon incorporation into the DNA inhibits further methylation, thus leading to gene activation. In order to test the second possibility we treated placental cells with interferon‐γ (IFN‐γ) or interleukin 4 (IL 4) which are known to induce class II antigen expression in many systems. We showed that treatment with 5‐AzaC or IFN‐γ but not IL 4 significantly increased class II expression on cytokeratin‐positive and vimentin‐negative adherent placental cells. Following placental cell fractionation we distinguished three cell subsets with different responsiveness to 5‐AzaC and IFN‐γ. The first, characterized as placental macrophages, were induced to express class II MHC antigens only after IFN‐γ treatment. The other two subsets, characterized as trophoblasts, were isolated from the labyrinthine‐ and spongio‐trophoblast layer of the placenta and showed class II inducibility to 5‐AzaC and IFN‐γ, respectively. The results show that depending on the anatomical localization of trophoblasts within the placenta, various regulatory elements control gene expression, so that the placental barrier provides fetal protection at different levels.
The CD3δ gene encodes multiple transcripts regulated by transcriptional and post‐transcriptional mechanisms
Authors: Wilkinson Miles F. , Georgopoulos Katia , Terhorst Cox , Macleod Carol L. 
Published: March 2007

AbstractCD3 is a multi‐subunit complex of proteins noncovalently associated with the T cell receptor (TcR) for antigen. Considerable evidence indicates a role for CD3 molecules in the transduction of activation signals in T cells. The murine CD3δ gene encodes a 0.7‐kb transcript present in mature T cells. Here we report the characterization of several additional CD3δ transcripts; two nuclear transcripts, 4–4.5 kb in size, and two predominately cytoplasmic transcripts of 1.5 kb and 2.5 kb. Both T lymphoma cell lines and normal thymocytes express the 1.5‐kb and 2.5‐kb CD3δ transcripts. These cytoplasmic transcripts have long 3'‐untranslated sequences which extend beyond the polyadenylation site of the predominant 0.7‐kb transcript. The protein synthesis inhibitor cycloheximide (CHX) increases the expression of all three cytoplasmic CD3δ transcripts, indicating that their level of expression may be regulated by a labile inhibitor protein(s). The CHX elicited increase in CD3δ mRNA appears to result from post‐transcriptional events since the rate of CD3δ gene transcription remains constant. In contrast to CHX, the calcium ionophore A23187 increases the rate of CD3δ gene transcription and, like CHX, also increases the level of cellular CD3δ mRNA. The immunosuppressive agent cyclosporin A inhibits A23187‐mediated stimulation of transcription, but has no effect on the CHX‐mediated induction of CD3δ mRNA. We conclude that both transcriptional and post‐transcriptional mechanisms can regulate the amount of all three cytoplasmic CD3δ transcripts.
Induction of antigen‐specific immunity with monoclonal anti‐idiotypic antibodies in vivo: differences in potency and comparison of immunochemical
Authors: Misplon Julia A. , Reeves James P. , Harvath Liana , Rubinstein Leonard J. , Epstein Suzanne L. 
Published: March 2007

AbstractAnti‐idiotypic (Id) antibodies provide a means other than antigen of clone‐specific regulation of immune responses, and have been proposed as an alternative form of vaccine. However, the requirements for effective induction of immunity by anti‐Id are not understood. Nine monoclonal anti‐idiotope antibodies (anti‐Id mAb) were derived in the Ia. 7 model system. While all nine anti‐Id mAb induced comparable Ab3 responses in vivo as detected by ELISA, there were dramatic differences in the potency of the antigen‐specific components of the responses induced by the nine anti‐Id mAb. Anti‐Id mAb that were indistinguishable in isotype, combining site relatedness, fine specificity on a panel of mAb, end point binding titers, competitive binding and ability to induce Ab3 differed dramatically in their ability to induce antigen‐specific immunity in vivo, thus ruling out several models for explaining differences in induction.
Glucocorticoid hormones reduce the expression of major histocompatibility class I antigens on human epithelial cells
Authors: von Knebel Doeberitz Magnus , Koch Susanne , Drzonek Heiko , Hausen Harald Zur 
Published: March 2007

AbstractExpression of a critical level of major histocompatibility complex (MHC) class I antigens on epithelial cells is a prerequisite for the action of specific cytolytic immune response cells. Glucocorticoid hormones have strong immunosuppressive effects. Therefore, we investigated the influence of the synthetic glucocorticoid dexamethasone on the expression level of MHC class I antigens on human epithelial cell lines. Long‐term treatment with dexamethasone leads to reduced MHC class I surface antigen expression and to decreased total membrane‐bound MHC class I protein. The steady‐state mRNA level is significantly decreased and the transcription rate of MHC class I genes is reduced.