bluuebunny/crossref_metadata_2025_split huggingface dataset:
CD2: a functional adhesion molecule on murine B cells, involved in interleukin‐4‐induced aggregation
Authors: Elenström‐Magnusson Carina , Altevogt Peter , Severinson Eva 
Published: March 2007

AbstractThe murine equivalent to CD2, previously known as a T cell marker, is expressed on mouse B cells. The monoclonal anti‐CD2 antibody 12‐15 was found to induce B cell homotypic adhesion. When treated with F(ab')2 fragments of 12‐15, purified, resting B cells aggregate within 2 h of incubation and the response is optimal after 20 h. Anti‐CD2‐induced aggregation is a dose‐related active process, dependent on temperature, metabolic energy and divalent cations. Aggregation is inhibited by two different Fab monomers of anti‐CD2, implying that it is the CD2 molecule itself that functions as an adhesion molecule. We also report that interleukin 4‐induced B cell homotypic adhesion involves CD2‐mediated cell binding, since the antibodies specific for mouse CD2, inhibited interleukin‐4‐induced cell aggregation.
Differential signaling through the Ig‐α and Ig‐β components of the B cell antigen receptor
Authors: Kim Kwang‐Myong , Alber Gottfried , Weiser Peter , Reth Michael 
Published: March 2007

AbstractThe B cell antigen receptor is a complex containing the antigen‐binding immunoglobulin molecules and the Ig‐α/Ig‐β heterodimer which presumably connects the B cell antigen receptor to intracellular signaling components. To analyze the functional properties of the cytoplasmic parts of the B cell antigen receptor, we used the K46 B lymphoma line (IgG2a, χ) to express chimeric molecules composed of the extracellular and transmembrane part of the CD8α molecule and the cytoplasmic sequence of either the Ig‐α (CD8α/Ig‐α), the Ig‐β (CD8α/Ig‐β) protein or the membrane‐bound γ2a heavy chain (CD8α/γ2a). From these three types of chimeric molecules only CD8α/Ig‐α and CD8α/Ig‐β, but not CD8α/γ2a, could transduce signals, thus providing the first evidence that the cytoplasmic tail of Ig‐α and Ig‐β have a signaling capacity. After cross‐linking with anti‐CD8α antibodies, both molecules induced a similar increase in intracellular free calcium ion and in MAP kinase phosphorylation. Protein tyrosine kinases, however, were strongly activated via the CD8α/Ig‐α and only marginally via the CD8α/Ig‐β molecule. This suggests that the Ig‐α and Ig‐β proteins have distinct roles during signal transduction through the B cell antigen receptor.
Human peripheral blood eosinophils produce and release interleukin‐8 on stimulation with calcium ionophore
Authors: Braun Ruedi K. , Franchini Marco , Erard Francois , Rihs Silvia , De Vries I. Jolanda M. , Blaser Kurt , Hansel Trevor T. , Walker Christoph 
Published: March 2007

AbstractWe present evidence that human blood eosinophils produce interleukin (IL)‐8 when stimulated with calcium ionophore. Following in vitro culture of 99 % pure eosinophils with calcium ionophore, released IL‐8 was detectable by enzymelinked immunosorbent assay in supernatants. Eosinophil IL‐8 production was considerably greater than that of IL‐3 or granulocyte macrophage colony‐stimulating factor. Furthermore, eosinophil production of IL‐8 in the presence of calcium ionophore could be inhibited with the immunomodulating agent cyclosporin A and the protein synthesis inhibitor cycloheximide. In addition, following stimulation of highly purified blood eosinophils with calcium ionophore, IL‐8 mRNA was detectable after polymerase chain reaction amplification. In comparison with other cells on stimulation with calcium ionophore, eosinophils produce about half as much IL‐8 as neutrophils but significantly more than purified T cells. In contrast to monocytes and neutrophils, IL‐8 production was not inducible with IL‐1 or tumor necrosis factor. Finally, following calcium ionophore stimulation blood eosinophils were shown to contain cytoplasmic IL‐8 by employing a monoclonal antibody against IL‐8 in conjunction with immuno‐histochemistry. These observations demonstrate that eosinophils are capable of IL‐8 production and release, which may contribute to defense against parasites and to the pathophysiology of allergic and asthmatic disease.
Human interleukin‐4 receptor signaling requires sequences contained within two cytoplasmic regions
Authors: Koettnitz Karl , Kalthoff Frank S. 
Published: March 2007

AbstractThe signaling pathway used by the murine or human interleukin‐4 receptor (WL‐4R) has not been elucidated so far. As an approach to mapping the cytoplasmic regions of the hIL‐4R that are essential for mediating the biological response upon IL‐4 binding we have cloned and expressed the wild‐type ML‐4R and several cytoplasmic deletion mutants in the murine IL‐3‐dependent pro‐B cell line BA/F3. Transfection of the wild‐type hIL‐4R conferred the ability on BA/F3 cells to proliferate in a dose‐dependent way when treated with human EL‐4. The analysis of six deletion mutants indicated that the signaling function of the hIL‐4R depends on sequences within two discontinuous regions that are located between amino acid He233 and Ser365 and Thr462 and Ala580 of the intracy toplasmic domain. The deletion of either of these regions totally abrogated IL‐4‐inducible growth. The relevance of our data is discussed in relation to the results obtaind from similar studies with other members of the hematopoietin receptor superfamily.
Peptides of 23 residues or greater are required to stimulate a high affinity class II‐restricted T cell response
Authors: Srinivasan Mallika , Domanico Susan Z. , Kaumaya Pravin T. P. , Pierce Susan K. 
Published: March 2007

AbstractHelper T cells recognize fragments of antigen bound to the class II molecules on the surface of antigen‐presenting cells. Naturally processed antigenic fragments have been isolated from the class II molecules and shown to be heterogeneous in length, ranging from 13 to 25 residues, and to vary at both the N and C termini. A 15‐residue peptide in an extended conformation is predicted to fit in an open peptide‐binding cleft of the class II molecules. Thus, the longer peptides observed bound to class II presumably have regions which reside outside the cleft. It is not known if the additional length contributes significantly to T cell activation. We have carried out a systematic analysis of the antigenicity of peptides of increasing length beyond the minimally defined T cell antigenic peptide. Here we show that the full functional activities of peptides representing the major antigenic determinant of the protein antigen, cytochrome c, minimally require that the peptides be 23 amino acids long. The long peptides do not require processing and are presented by purified class II molecules incorporated into synthetic membranes, indicating that such peptides associate directly with class II and require no additional cellular machinery for presentation. We also show that a hybrid peptide, 51 residues in length, containing a 29‐residue cytochrome c peptide and a “promiscuous” peptide of tetanus toxoid, is more antigenic than the 23‐residue peptide alone and significantly, does not require processing. Thus, the additional peptide length, although not predicted to bind in the peptide‐binding groove of the MHC class II molecule, has a significant impact on the ability of the peptides to stimulate T cell responses maximally.
The fate of human peripheral blood lymphocytes after transplantation into SCID mice
Authors: Martino Gianvito , Anastasi John , Feng Jiajia , Shan Carol Mc , Degroot Leslie , Quintans Josè , Grimaldi Luigi M. E. 
Published: March 2007

AbstractHuman peripheral blood lymphocytes (hu‐PBL) can be adoptively transferred by intraperitoneal injection into mice with severe combined immunodeficiency (SCID). The transplanted lymphocytes can produce immunoglobulin (Ig), respond to antigens, and survive for months in this chimeric model (hu‐PBL SCED). However, whether the lymphocytes actually repopulate and reconstitute lymphoid structures and organs has been subject of some debate. To address this question and to characterize the hu‐PBL SCID model better, we employed a novel technique for the identification of human cells in xenogeneic mice. We used fluorescence in situ hybridization (FISH) with a biotinylated DNA probe to all human centromeres. We demonstrated that FISH could be used to detect human cells when they accounted for less than 1 % of human/mouse cell mixtures; it could also be employed for the identification and localization of individual human cells in tissue sections. By using FISH, we studied 31 SCID mice injected with 1.5 × 107 −4 × 107 hu‐PBL via intravenous (i.v.) or intraperitoneal (i.p.) routes. In the 6 i.v ‐injected mice, we found that the human cells were removed from the circulation into the lung within 1 h. In 22 of 25 i.p ‐injected animals, 90–3716 μg/ml of human IgG was found in the sera at 3 to 13 weeks after transplantation (a.t.). Human cells colonized the peritoneal cavity and persisted for up to 13 weeks a.t. and, in the 12 mice studied, accounted for 4 % to 57 % of the cells in the peritoneal fluid. However, only rare, isolated human cells were found in the spleen, blood, bone marrow, lung or Peyer's patches. In 7 of 19 mice that received hu‐PBL i.p. from Epstein‐Barr virus‐seropositive donors, we found masses of human cells usually beneath the peritoneal lining but sometimes infiltrating normal tissue. We conclude that FISH offers a simple means for accurate identification of human cells in the xenogeneic mouse. Although there is colonization of the peritoneal cavity in most mice, and development of lymphoid masses in some, there is no reconstitution of lymphoid structures and only minimal engraftment of lymphoid organs by human cells in conventionally‐prepared hu‐PBL SCID constructs.
Linkage disequilibrium between TAP2 variants and HLA class II alleles; no primary association between TAP2 variants and insulin‐dependent diabetes mellitus
Authors: Rønningen Kjersti S. , Undlien Dag E. , Ploski Rafal , Maouni Nicki , Konrad Robert J. , Jensen Elisabeth , Hornes Erik , Reijonen Helena , Colonna Marco , Monos Dimitri S. , Strominger Jack L. , Thorsby Erik 
Published: March 2007

AbstractThe TAP1 and TAP2 genes, located in the HLA class II region, encode subunits of a peptide transporter. Both genes display limited genetic variability; four different nucleotide substitutions have been found in theTAP2 gene. Here studies on linkage disequilibrium between TAP2 variants and HLA class II alleles are reported, in an attempt to evaluate whether TAP2 variants are associated with insulin‐dependent diabetes mellitus (IDDM). As reported previously, a significant decrease of homozygosity for TAP2 alleles encoding alanine at residue 665 (665 Ala) and glut amine at 687 (687 Gin) paralleled by an increase in homozygosity for TAP2 alleles encoding threonine at residue 665 (665 Thr) and a stop codon at 687 (687 Stop), was found in both Finnish and Norwegian IDDM patients compared to random controls. However, a strong linkage disequilibrium between these TAP2 polymorphisms and given HLA‐DR and ‐DQ genes was observed among healthy controls. The frequent 665 Thr and 687 Stop variants were in linkage disequilibrium both with the DR4‐DQ8 and the DR3‐DQ2 haplotypes, haplotypes which are strongly associated with IDDM. In contrast, the DR1‐DQ5 and DR13‐DQ6 (e.g. DQB1*0603) haplotypes, which are decreased among IDDM patients, were associated with the 665 Ala and 687 Gin variants. Thus, when DR‐ and DQ‐matched patients and controls were compared, associations of the investigated TAP2 variants and IDDM were no longer detectable. These data, therefore, indicate that the associations previously found between certain TAP2 variants and IDDM are secondary to a primary association between this disease and particular DQαβ heterodimers.
Age‐related accumulation of LFA‐1high cells in a CD8+CD45RAhigh T cell population
Authors: Okumura Meinoshin , Fujii Yoshitaka , Takeuchi Yukiyasu , Inada Keiji , Nakahara Kazuya , Matsuda Hikaru 
Published: March 2007

AbstractThe differential expression of CD45 isoforms has been suggested as a marker for stages of post‐thymic T cell development, that is, CD45RA+CD45R0− T cells and CD45RA−CD45R0+ T cells are supposed to be virgin and memory cells respectively. Recently, several adhesion molecules have been shown to be up‐regulated on the cell surface of memory T cells, and have been suggested to serve as a memory marker. In this study, we investigated the levels of LFA‐1 expression on T cells in various subpopulations defined by CD45 isoform expression in donors of various ages.In CD4+ T cells, the proportion of LFA‐1high cells among CD45RAhighCD45R0‐T cells remained low in all age groups and did not show significant accumulation with age. CD4+CD45RA−CD45R0highTcells expressed LFA‐1 at a higher level than CD4+CD45RAhighCD45R0− T cells. Thus, the currently prevailing view that CD45RA and CD45R0 can be markers for virgin and primed cells was consistent with LFA‐1 expression in CD4+ T cell population.In CD8+ T cells, however, CD45RAhighCD45R0− T cells consisted of two distinct subpopulations, LFA‐1low and LFA‐1high cells, whereas CD45RA−CD45R0high T cells were almost exclusively LFA‐1high When CD29 expression was examined in place of LFA‐1 expression, similar results were obtained; CD45RAhigh CD45R0− T cells consisted of two distinct subpopulations, CD29‐to low and CD29high cells, while CD45RA‐CD45R0high T cells were mostly CD29high.The proportion of LFA‐1high cells in the CD8+CD45RAhigh T cell subpopulation increased significantly as a function of age (r = 0.9, p < 0.001). It ranged from 8% in a 14‐year‐old donor to 94% in a 79‐year‐old donor. Furthermore, the proportion of CD8+CD45RAhighLFA‐1high cells in the CD8+ T cell population increased significantly as a function of age (r = 0.85, p < 0.001). On the other hand, the proportion of LEA‐1high cells in CD8+CD45RA− T cell subpopulation exceeded 90% in most donors irrespective of age.These results indicate that the CD8+CD45RAhighCD45R0− T cell subpopulation contains a considerable number of LFA‐1high cells and CD29high cells, phenotypically similar to previously activated cells. Thus, in terms of LFA‐1 and CD29 expressions, the simple scheme that CD45RA is a marker of virgin cells is not applicable to the CD8+ T cell population.
Human CD3−CD16+ natural killer cells express the hGATA‐3 T cell transcription factor and an unrearranged 2.3‐kb TcR δ transcript
Authors: Biassoni Roberto , Verdiani Simonetta , Cambiaggi Anna , Romeo Paul‐Henri , Ferrini Silvano , Moretta Lorenzo 
Published: March 2007

AbstractIn this study we analyzed the Tcell receptor(TcR) δ transcripts expressed by CD3−CD16+ cells and we investigated whether these cells expressed the hGATA‐3 Tcell transcription factor and the recombination‐activating gene (RAG)‐l.Multiple TcR δ transcripts deriving from an unrearranged TcR δ gene were detected in both polyclonal and clonal CD3−CD16+ natural killer(NK) cell lines. Two unrearranged TcR δ transcripts had a size similar to that of the functional TcR δ mRNA (2.3 and 1.3 kb) found in TcR γ/δ+ T lymphocytes. Sequence analysis of nine different 2.3‐kb cDNA clones obtained from NK‐derived polyA+ RNA confirmed that they corresponded to an unrearranged TcR δ gene. These cDNA were 2343 bp long and their transcription initiation site was located 814 bp upstream from the Jδ1 segment. The sequence located upstream of the Jδ1 segment corresponded to the previously reported germ‐line sequence. The Jδ1 segment was correctly spliced to Cδ; in addition the four Cδ exons were found to be already assembled. Two polyadenylation sites were present in the fourth Cδ exon. However, only that located at the 3′ end appeared to be utilized in the 2.3‐kb cDNA. The expression of hGATA‐3, a T cell‐specific factor known to be involved in the regulation of the transcription of TcR δ locus, was analyzed by Northern blot, in cultured NK cell population and clones (but not in freshly derived cell populations). All NK clones and cell lines studied were found to express hGATA‐3‐specific mRNA, suggesting that hGATA‐3 may be involved in the regulation of the unrearranged TcR δ gene expression in NK cells. Finally, no transcription of the RAG‐1 gene could be detected in all NK cell lines or clones analyzed.
Real‐time measurement of antigenic peptide binding to empty and preloaded single‐chain major histocompatibility complex class I molecules
Authors: Ojcius David M. , Godeau François , Abastado Jean‐Pierre , Casanova Jean‐Laurent , Kourilsky Philippe 
Published: March 2007

AbstractCytotoxic T lymphocytes (CTL) recognize peptides in association with major histocompatibility complex (MHC) class I proteins, but how peptides bind to class I is not well understood. We used a fluorescence technique to measure antigenic peptide binding to a soluble, single‐chain Kd (SC‐Kd) molecule in which the Kd heavy chain was connected by a 15‐residue link to β2‐microglobulin. Peptides were covalently labeled at their N terminus with dansyl, and binding of dansylated Kd‐restricted peptides to SC‐Kd resulted in significant fluorescence enhancement, which could be inhibited by unmodified Kd‐restricted peptides. Real‐time binding of a dansylated peptide could be followed by monitoring the fluorescence at 530 nm. The dansylated Plasmodium berghei circumsporozoite (PbCS) 263–260 peptide bound to “empty” SC‐Kd with an association rate constant of 1140 M−1s−1, and the subsequent spontaneous dissociation of the SC‐Kd‐peptide complex was slow. The dissociation increased dramatically after addition of excess unlabeled PbCS 253–260 peptide, but with a slower association constant for unlabeled peptide, 77 M−1s−1. Thus, the Kd‐peptide complex on the surface of antigen‐presenting cells should be stable, but high concentrations of peptides in the endoplasmic reticulum (ER) lumen would allow for peptide exchange on Kd before export to the surface. The apparent activation energy for PbCS 253–260 peptide binding to SC‐Kd was 6.78 ± 0.64 kcal/mole, similar to values previously reported for antigen‐antibody interactions.
86Rb+ ion fluxes in resting and immunologically stimulated mucosal mast cells
Authors: Pilatus Ulrich , Pecht Israel 
Published: March 2007

AbstractWe studied fluxes of Rb+ ions, using its 86Rb isotope as a radioactive tracer in living rat mucosal mast cell cultures (RBL‐2H3 line) grown to high density on beads. Continuously perfused samples of these cells could be immunologically stimulated by antigen clustering of IgE bound to the cells type I Fee receptors (FcεRI) and both the cellular response, as measured by the secreted mediators, as well as the uptake of 86Rb+ of the perfused sample could be monitored.The following results were obtained, (i) In resting cells, 86Rb+ influx is observed upon exposure to extracellular 86Rb+. It proceeds with a monoexponential time course (τ = 30.6 ± 8 min) reaching a steady‐state distribution of [86Rb+]int/[86Rb+]ext = 31.6 ± 6.4 and can be inhibited by ouabain, (ii) FcεRI clustering‐mediated stimulation of these cells causes an immediate and marked increase in both amplitude and rate of 86Rb+ uptake, which also fits a monoexponential function (τ = 26.8 ± 8.6 min). (iii) This stimulated 86Rb+ uptake can also be inhibited by ouabain. It is not caused by Ca2+ influx or by the exocytotic process as evidenced by the fact that it is also observed in buffer to which no Ca2+ ions were added. Analysis of these results by a simple model taking into account unidirectional 86Rb+ influx by the Na+/K+‐dependent ATPase and its efflux by K+ channels yields a resting cells unidirectionel K+ uptake of 3.0 ± 1.1 107 ions/cell/s, which is increased by ca. 10% upon clustering of the FcεRI by IgE and antigen. The stimulated influx is suggested to be due to enhanced activity of the Na+/K+‐dependent ATPase, reflecting increased permeability for Na+ ions.
Physical association of CD5 and the T cell receptor/CD3 antigen complex on the surface of human T lymphocytes
Authors: Osman Narin , Lazarovits Andrew I. , Crumpton Michael J. 
Published: March 2007

AbstractThe physical association of CD5 and the Tcell antigen receptor (TcR)/CD3 complex on the surface of intact human lymphocytes was investigated using co‐capping experiments and fluorescence resonance energy transfer (FRET) analyses. Antibody‐induced capping of CD5 or CD3 and double indirect immunofluorescence labeling revealed a specific co‐localization of a significant fraction of CD3 and CD5 molecules on the Tcell surface. By means of FRET measurements we studied further the physical proximity of CD5 and the TcR/CD3 complex at the surface of normal lymphocytes. Significant fluorescence energy transfer was measured between CD5 and CD3 molecules indicating that the associated molecules were within 10 nm of one another. No energy transfer was observed between the integrin α4β7 and CD3 or CD5. The close physical proximity measured between CD5 and CD3 correlates with our co‐capping data and taken together the results show that the association of CD5 and the TcR/CD3 complex first detected by immunoprecipitation occurs on the surface of human T cells under physiologically relevant conditions.
Lymphocytes bearing the γδ T cell receptor in acute Brucella melitensis infection
Authors: Bertotto Alberto , Gerli Roberto , Spinozzi Fabrizio , Muscat Christopher , Scalise Francesco , Castellueei Giuseppe , Sposito Maddalena , Candio Francesco , Vaeearo Renato 
Published: March 2007

AbstractA phenotypical analysis carried out by indirect immunofluorescence and two‐color cytofluorometry showed that the number of lymphocytes bearing the γδ T cell receptor (TcR) heterodimer was dramatically increased in the blood of six children with Brucella melitensis infection. Most in vivo expanded γδ T cells reacted with a monoclonal antibody which identifies Vδ2 gene products and a significant proportion expressed CD25 and HLA‐DR activation antigens. In addition, whereas only a few γδ T lymphocytes were CD8+, nearly all were CD4−. Highly enriched populations of both αβ and γδ T cells were obtained by negative immunoselection from three subjects with brucellosis sampled during convalescence. Despite the different form of their TcR, the proliferation of these two major T cell subsets in response to a mitogenic anti‐CD3 monoclonal reagent (OKT3) was optimal. In contrast, αβ, but not γδ, T lymphocytes proliferated vigorously in response to the antigenic stimulus elicited by heat‐killed Brucella. Further studies are, therefore, needed to determine whether the selective expansion of the γδ T cell subpopulation observed during the clinical course of the infection is driven by antigenic determinant(s) borne by the pathogen in vivo or is due to host‐derived stimuli, such as autologous heat‐shock proteins expressed on the surface of the infected cells.
Strict peptide length is not required for the induction of cytotoxic T lymphocyte‐mediated antiviral protection by peptide vaccination
Authors: Kast W. Martin , Brandt Remco M. P. , Melief Cornelis J. M. 
Published: March 2007

AbstractSendai virus nuclear protein peptides of different lengths were titrated in peptide vaccination experiments. We observed that peptide length was not important in inducing cytotoxic T lymphocyte‐mediated protective immunity in vivo against a challenge with a lethal dose of virus. These results suggest that long peptides are trimmed in vivo to peptides that fit into the groove of major histocompatibility complex class I molecules. In addition several adjuvants were screened for their effectiveness in peptide vaccination protocols. Incomplete Freund's adjuvant and Titermax™ turned out to be useful, whereas alum was much less effective.