bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polarity of immunogens: implications for vaccine design
Authors: Golvano José , Lasarte Juan J. , Sarobe Pablo , Gullón Arturo , Prieto Jesús , Borrás‐Cuesta Francisco 
Published: March 2007

AbstractPeptide constructs have been engineered consisting of amino acid sequence determinant recognized by T cells (TD) co‐linearly linked to haptenic peptides. It was found that high anti‐hapten antibody titers were induced after immunization with those constructs which had the TD sequence in the N‐terminal position with respect to the hapten. Low or zero titers were elicited when the TD was in C‐terminal position. Also, a high anti‐hapten antibody titer corresponded to a low or zero anti‐TD antibody titer and vice versa. These results suggest that immunogens are polar and stress the relevance of searching the more adequate position of the TD within a peptide construct when designing immunogens or synthetic peptide vaccines.
Interleukin 4 down‐regulates the expression of CD14 in normal human monocytes
Authors: Lauener Roger P. , Goyert Sanna M. , Geha Raif S. , Vercelli Donata 
Published: March 2007

AbstractRecombinant interleukin 4 (IL 4) down‐regulates the expression of CD 14 on normal human monocytes, as assessed by flow cytometry, binding assays with radiolabeled anti‐CD 14 monoclonal antibody (mAb), and immunoprecipitation of 125I‐labeled monocytes with anti‐CD14 mAb. In parallel, CD23 expression on monocytes was strongly increased by IL4 stimulation, as assessed by both flow cytometry and immunoprecipitation. Down‐regulation of surface CD14 was first detectable after 24–36 h of incubation with rIL 4, and was almost complete after 4 days of culture. None of the other recombinant lymphokines tested (IL 1, IL 2, IL 3, IL 5, IL 6, interferon‐γ, tumor necrosis factor α and β, granulocytemacrophage colony‐stimulating factor) decreased CD14 expression. Metabolic labeling studies with [35S]methionine showed that both the membrane‐associated and the soluble form of CD 14 are decreased by IL 4 stimulation. Northern blot analysis showed that incubation of monocytes with IL 4 induced a marked decrease in CD 14 mRNA. Nuclear run‐off assays revealed that the IL 4‐dependent down‐regulation of CD 14 resulted from decreased transcription. Thus, IL 4 exerts specific and opposite effects on the expression of monocytic antigens.
Differential effects of low and high concentrations of interleukin 6 on human B cells
Authors: Levy Yves , Fermand Jean‐Paul , Brouet Jean‐Claude 
Published: March 2007

AbstractIn this report we have studied the functional effects of a wide range of interleukin 6 concentrations on human B cells. B cells purified from tonsils and from five of six spleens proliferated directly in a dose‐dependent manner in the presence of low concentrations (1–100 ng/ml) of IL 6 whereas B cells from the sixth spleen proliferated only after in vitro anti‐μ antibodies activation. Only large B cells (presumably in vivo activated B cells) were responsive to IL 6. High concentrations of IL 6 (1–10 ng/ml) did not trigger B cell proliferation but were able to up‐regulate the expression of the B5 activation antigen on B cells, whereas the expression of two other B cell antigens (CD20 and CD23) was unchanged. At all concentrations of IL 6 tested (0.01–10 ng/ml) no B cell differentiation occurred after 7 days culture. Depletion before culture of B5+ cells from the B cell‐enriched spleen cell preparation abolished both the proliferative effect and up‐regulation of B5 antigen induced by IL 6, indicating that this lymphokine acted primarily on activated B cells. This differential effect of “low” and “high” concentrations of IL 6 on activated B cells may solve controversy on the role of IL 6 as an early or late agent in B cell maturation.
Spontaneous production of anti‐mouse red blood cell autoantibodies is independent of the polyclonal activation in NZB mice
Authors: Reininger Luc , Shibata Takanori , Schurmans StéPhane , Merino Ramon , Fossati Liliane , Lacour Marc , Izui Shozo 
Published: March 2007

AbstractNew Zealand Black (NZB) mice spontaneously develop an autoimmune hemolytic anemia together with a markedly increased production of polyclonal antibodies. The spontaneous generation of anti‐mouse red blood cells (MRBC), anti‐bromelain‐treated MRBC (BrMRBC) and anti‐DNA autoantibodies was compared to the polyclonal antibody formation in irradiated (800 rad) 2‐month‐old NZB mice reconstituted with bone marrow cells (BMC) from 2‐ or 10‐month‐old NZB mice. The injection of 10‐month‐old NZB BMC markedly accelerated the mortality rate in parallel with the progressive increase of anti‐MRBC and anti‐BrMRBC autoantibody production, but the spontaneous production of polyclonal IgM antibodies and anti‐DNA autoantibodies was completely abolished down to the levels of non‐autoimmune mice. In contrast, mice reconstituted with 2‐month‐old NZB BMC exhibited neither the acceleration of anemia nor the lack of polyclonal antibody production. These results strongly suggest that the spontaneous production of anti‐MRBC autoantibodies, including anti‐BrMRBC autoantibodies, in the NZB mouse occurs independently of the polyclonal B cell activation, and that they result from a specific immune stimulation, while the anti‐DNA autoantibody production is a consequence of polyclonal antibody formation.
The effect of mutations in the MHC class I peptide binding groove on the cytotoxic T lymphocyte recognition of the Kb‐restricted ovalbumin determinant
Authors: Nikolić‐Žugić Janko , Carbone Francis R. 
Published: March 2007

AbstractThe H‐2Kb‐restricted cytotoxic T lymphocyte (CTL) response directed against ovalbumin (OVA) is specific for a region contained within the sequence OVA253‐276. In this study we have characterized this response by examining the class I‐restricted presentation of OVA peptides by the naturally occurring Kb mutant (Kbm) glycoproteins Kbm1, Kbm3, Kbm5, Kbm8, Kbm10, Kbm11 and Kbm23. To facilitate this study we derived a series of somatic cell hybrid targets expressing the various Kbm class I molecules. Experiments using bulk OVA‐specific CTL from C57BL/6 mice demonstrated that all the Kbm molecules except for Kbm1 and Kbm8 could present OVA peptides for effective T cell recognition. Clonal analysis revealed a more complex and relatively diverse pattern of CTL recognition of the Kbm/peptide combinations. This diversity is unlikely to result from the existence of multiple, independent Kb‐restricted T cell determinants within OVA, since all CTL tested were specific for a single region between residues 259 and 273. Examination of the fine specificity of Kbm presentation identified individual changes at residues 77, 80 and 116 which affected T cell recognition. The results imply that these changes do not inhibit peptide binding since some clones could recognize peptide presented by a particular Kbm molecule, while other clones could not. All three residues reside within the peptide‐binding cleft of the class I protein and are not expected to directly contact the T cell receptor. Although we did not formally demonstrate that OVA binding by Kbm vs. Kb is quantitatively identical, our results are best explained by postulating that the changes at residues 77, 80 and 116 indirectly affect T cell recognition by altering peptide conformation. Taken together our results suggest that changes within the class I binding site can profoundly modify peptide presentation without significantly inhibiting peptide‐class I association.
Natural killer susceptibility is independent of HLA class I antigen expression on cell lines obtained from human solid tumors
Authors: Peña Jose , Alonso Corona , Solana Rafael , Serrano Rafael , Carracedo Julia , Ramirez Rafael 
Published: March 2007

AbstractThe susceptibility to natural killer (NK) cell‐mediated cytotoxicity of 20 cell lines obtained from human solid tumors and their class I histocompatibility antigen (HLA) levels were studied in an attempt to determine whether major histocompatibility complex (MHC) products expressed on cells derived from human solid tumors influence NK susceptibility. The effect of interferon‐γ (IFN‐γ) treatment on these elements was also analyzed. The MHC class I (HLA‐ABC, HLA‐A and HLA‐B) antigen levels and degree of NK lysis were very heterogeneous and no correlation was found on comparison. After treatment with IFN‐γ a marked decrease in NK susceptibility was observed in all the cell lines, including the control line K‐562. However, the level of HLA class I expression was not modified in any of the lines with the exception of the K‐562, which increased. In some cell lines the expression of HLA class I‐like antigens, CD1a, b and c, was also measured before and after IFN treatment; however, no correlation was found between CD1 levels and NK susceptibility. Consequently, from our results it is possible to conclude that HLA class I antigens do not play a decisive role in NK susceptibility of cell lines derived from human solid tumors and to suggest that molecules which are not HLA class I antigens but IFN‐γ inducible may confer NK resistance to these lines.
Functional implication for the topographical relationship between MHC class II and the low‐affinity IgE receptor: occupancy of CD23 prevents B lymphocytes from stimulating allogeneic mixed lymphocyte responses
Authors: Flores‐Romo Leopoldo , Johnson Gerald D. , Ghaderi Abbas A. , Stanworth Dennis R. , Veronesi Arianna , Gordon John 
Published: March 2007

AbstractFollowing the observation of Bonnefoy et al. (J. Exp. Med. 1988. 167: 57), that the low‐affinity IgE receptor (CD23) on B lymphocytes can be coupled (with the use of chemical cross‐linking reagents) to major histocompatibility complex (MHC) class II DR molecules, we now report that ligands binding within the lectin‐homology region of CD23 prevent B cells from stimulating allogeneic mixed lymphocyte responses. Ligands capable of blocking mixed lymphocyte responses include the anti‐CD23 antibodies MHM6 and EBVCS 4 but not EBVCS 1 and 5, IgE itself, and small peptides representing sequences within the CH3 domain of IgE. The detailed topographical relationship between CD23 and MHC class II on the B lymphocyte surface was examined using dual immuno‐fluorescence labeling of cells and direct visualization of the staining by confocal laser scanning microscopy. On transformed B lymphoblasts, the two antigens were seen to co‐localize in discrete patches; on normal B cells which had been cultured for 2 days with interleukin 4, CD23 and MHC class II converged at a single pole which exhibited a tendency to pseudopod formation and provided a focus for homotypic cell‐cell interactions. The possibility that CD23 could serve as a co‐stimulatory‐adhesion molecule in antigen presentation by B lymphocytes is discussed with special reference to a potential role in the regulation of IgE synthesis.
J chain deficiency in human IgM monoclonal antibodies produced by Epstein‐Barr virus‐transformed B lymphocytes
Authors: Gloria Meng Y. , Criss Anne B. , Georgiadis Katy E. 
Published: March 2007

AbstractSix human IgM monoclonal antibodies against Pseudomonas aeruginosa were purified and characterized. On agarose‐acrylamide sodium dodecyl sulfate (SDS) gels run under nonreducing conditions, IgM monoclonal antibodies showed variable amounts of a slower migrating form of IgM in addition to the one co‐migrating with plasma IgM. Protein blotting with anti‐J chain antibody showed that the slower migrating form did not contain J chain. Analysis of one of the monoclonal antibodies by sucrose gradient centrifugation showed that the J chain‐deficient form sedimented faster than the complete IgM. It is known that IgM preparations lacking J chain sediment faster by sucrose gradient centrifugation analysis and tend to form hexamers. The slower migrating form of IgM we observed on SDS gels under nonreducing conditions could be hexameric IgM. Further evaluation of this monoclonal antibody demonstrated that both forms of IgM had the same antigen‐binding activity. Glycosylation of the light chain was demonstrated in two of the monoclonal antibodies.
In vitro analysis of age‐related changes in the developmental potential of bone marrow thymocyte progenitors
Authors: Sharp Ayala , Kukulansky Tova , Globerson Amiela 
Published: March 2007

AbstractMechanisms underlying the age‐related decrease in the developmental capacity of thymocyte progenitors from the bone marrow (BM) were analyzed, focussing on interactions of these cells with the thymic microenvironment. We employed the experimental model in which mixtures of young and old mouse BM cells, congenic for the Thy‐1 marker, were seeded onto fetal thymus (FT) explants depleted of self lymphocytes and the levels of Thy‐1+ cells developing from each of the two donor types were measured. When cells from young and old BM donors were seeded simultaneously, in saturating quantities, a higher level of T cells developed from the young donors.To find out whether there were originally more thymocyte progenitors in the young BM, we carried out the competitive colonization under limiting dilution conditions and found that the advantage of the young had diminished under these conditions, thus suggesting that the age‐related changes could not be related solely to quantitative differences. We then incubated the FT sequentially with old donor cells for 24 h, followed by young for an additional 48 h and found that the advantage of the young progenitors was eliminated. We thus established that the initial stage of colonization of the FT was important in determining the outcome of the subsequent development. The kinetics of simultaneous competition within the FT, however, revealed that the advantage of the young BM‐derived cells became significant only from day 7 in organ culture, thus suggesting that sequential divisions of these cells were at a higher level than those of the old. Recolonization of FT explants by young or old BM‐derived thymocytes obtained from the first colonization of the FT stroma showed a reduced, but still significant advantage for the young BM‐derived cells over the old. Thus, we concluded that the old BM thymocyte progenitors manifested a qualitative disadvantage which became apparent during competitive colonization of the FT.
Genetic recombination in the α2 domain of the Eα chain yields an Ed molecule with altered T cell activation
Authors: Chang Ming‐Der Y. , Kowal Czeslawa , Marzullo Laurie R. , Briner Thomas J. , Gefter Malcolm L. , Diamond Betty 
Published: March 2007

AbstractWe have used a novel T cell selection strategy to isolate a mutant of an H‐2d/f murine macrophage line defective in its ability to present antigen to some Ed‐restricted helper T cells. This mutant has an amino acid substitution in the α2 domain of the Ed molecule. The mutation changes the sequence at codon 177 from ACC to CAC, which results in a threonine to histidine substitution and appears to be the first in vitro mutation to have arisen by genetic recombination. Even though the mutation is distal to the proposed antigen‐binding groove, it affects antigen presentation, presumably by altering the scaffolding for the antigen‐binding groove. This type of mutant might not be readily isolated using other selection techniques.
Thyroid‐derived epithelial cells acquire alloantigen‐presenting capabilities following X‐irradiation and class II antigen induction
Authors: Czirjak Laszlo , Danko Katalin , Gaulton Glen N. , Stadecker Miguel J. 
Published: March 2007

AbstractThis work was undertaken to further define the antigen‐presenting capabilities of thyroid epithelial cells, as this is of paramount importance with regard to their potential to trigger autoimmune thyroiditis. For this purpose we developed the murine cloned thyroid‐derived epithelial cell line M.5 which, as previously reported, could be induced to express class II antigens with interferon (IFN)‐γ, but failed to stimulate a primary mixed leukocyte reaction.We now show that M.5 cells acquired alloantigen‐presenting function, under conditions in which their replication was arrested by X‐irradiation, during a 4‐day period of exposure to UV‐inactivated reovirus, or to IFN‐γ, for induction of class II antigens.The allostimulatory function by M.5 cells could not be explained on the basis of enhanced class II antigen expression, as equivalent numbers of M.5 cells, irradiated after the 4‐day exposure to reovirus, or to IFN‐γ, expressed higher amounts of class II antigens, but did not stimulate a primary mixed leukocyte reaction. Early X‐irradiation appeared to induce in the class II‐expressing M.5 cells a co‐stimulatory signal needed for T cell proliferation, similar to that otherwise provided by phorbol esters in this system. Preservation of alloantigenpresenting function by M.5 cells following fixation indicated that this costimulatory activity did not reside in a soluble molecule.We surmise that M.5 epithelial cells must provide a least two signals in order to be able to stimulate lymphocyte populations. Consequently, the mode and conditions of epithelial cell activation may determine whether these cells acquire the capacity to serve as antigen‐presenting cells, and ultimately whether or not they are able to induce autoimmune disease.
Evidence that in X‐linked immunodeficiency with hyperimmunoglobulinemia M the intrinsic immunoglobulin heavy chain class switch mechanism is intact
Authors: Hendriks Rudolf W. , Kraakman Margriet E. M. , Craig Ian W. , Espanol Teresa , Schuurman Ruud K. B. 
Published: March 2007

AbstractX‐linked immunodeficiency with hyperimmunoglobulinemia M (XHM) reflects an impairment of the immunoglobulin (Ig) heavy (H) chain class switch of B lymphocytes from IgM to IgG and IgA.XHM is recessive; female carriers manifest normal IgG and IgA production. Due to random X chromosome inactivation in all somatic cells of females, about half of the lymphocytes of XHM carriers are not able to express an intact XHM gene. An intrinsic defect of the Ig H chain class switch mechanism in XHM B lymphocytes would thus lead to a skewed X chromosome inactivation pattern in the IgG‐ and IgA‐expressing B lymphocytes of female carriers.IgM‐, IgG‐ and IgA‐expressing B lymphoblastoid cells (BLC) were established by Epstein‐Barr virus transformation of peripheral blood mononuclear cells of two female XHM carriers. In an analysis of differential methylation of the polymorphic DXS255 loci, random X chromosome inactivation patterns were found in populations of T lymphocytes, in IgM‐expressing B lymphocytes and in IgG‐ or IgA‐expressing B lymphocytes. The heterogeneity of Ig H chain rearrangements and the Ig light chain usage in the IgA‐ or IgG‐expressing BLC clones that had inactivated the X chromosome which carries the intact XHM gene and in BLC clones with the homologous X chromosome inactivated were similar.The results indicated that the intrinsic Ig H chain class switch mechanism in XHM B lymphocytes is fully intact. We conclude that the XHM gene encodes a class switch inducer that is transferred to B lymphocytes.
Processing without proteolytic cleavage is required for recognition of insulin by T cells
Authors: Gradehandt Gernot , Hampl Johannes , Milbradt Silke , Rüde Erwin 
Published: March 2007

AbstractBeef insulin as well as a chymotryptic A‐chain fragment [BI‐A1‐14(SSO3−)3] need uptake by antigen‐presenting cells (APC) for efficient presentation in combination with major histocompatibility complex class II molecules to insulinspecific T cells. This could be shown by the inability of aldehyde‐fixed APC to present these antigens to T cells. Furthermore, presentation of the insulin fragment as well as presentation of ovalbumin (OVA) was inhibited by treatment of APC with chloroquine, cerulenin or tunicamycin. This was not the case for a processing‐independent OVA peptide. Treatment of APC during antigen pulsing with various protease inhibitors, active on all classes of proteases, did not block presentation of insulin although some of these reagents did interfere with the presentation of OVA. Several inhibitors especially of serine or thiol proteases rather enhanced the presentation of insulin. This indicates that intracellular proteolytic cleavage of insulin does not seem to be required for generation of the antigenic determinant but, if it occurs, rather destroys the antigenic peptide. Insulin and its A‐chain fragment may, therefore, represent a model for a processing‐dependent antigen not requiring proteolytic cleavage but other modifications.
Cloning and sequencing of human λ immunoglobulin genes by the polymerase chain reaction
Authors: Songsivilai Sirirurg , Bye Jacqueline M. , Marks James D. , Hughes‐Jones Nevin C. 
Published: March 2007

AbstractUniversal oligonucleotide primers, designed for amplifying and sequencing genes encoding the rearranged human λ immunoglobulin variable region, were validated by amplification of the λ light chain genes from four human heterohybridoma cell lines and in the generation of a cDNA library of human Vλ sequences from Epstein‐Barr virus‐transformed human peripheral blood lymphocytes. This technique allows rapid cloning and sequencing of human immunoglobulin genes, and has potential applications in the rescue of unstable human antibody‐producing cell lines and in the production of human monoclonal antibodies.
VH and VL region structure of antibodies that recognize the (NANP)3 dodecapeptide sequence in the circumsporozoite protein of Plasmodium falciparum
Authors: Anker Roberto , Zavala Fidel , Pollok Brian A. 
Published: March 2007

AbstractThe sporozoite form of Plasmodium falciparum displays on its surface the circumsporozoite (CS) protein. The central domain of this protein possesses a reiterated tetrapeptide sequence Asn‐Ala‐Asn‐Pro (NANP), and > 90% of the sporozoite‐specific antibodies obtained from individuals living in malaria endemic areas recognize epitopes within this repeat sequence. Considering the highly repetitive structure of this naturally occurring antigen and its immunodominance, we were interested in analyzing the structural diversity of antibodies that bind to the (NANP)3 sequence. Molecular characterization of immunoglobulin heavy and light chain mRNA was performed for five hybridomas that produce antibodies with binding specificity for the dodecapeptide (NANP)3. These hybridomas were produced in BALB/c mice by inoculation with whole P. falciparum sporozoites. Sequence analysis and Northern blotting showed that for heavy chain, three hybridomas used VH elements that belong to the VHIX family and two to the VHJ558 family. Four different Vχ subgroups were represented among the light chains. Different D and Jχ segments are also utilized, while four heavy chain gene rearrangements involved the JH4 segment. These results indicated that multiple VH‐VL gene combinations can code for reactivity to the (NANP)3 sequence, demonstrating that the murine antibody response to this immunodominant region is structurally heterogeneous.