bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular cloning of cDNAs for the rat interleukin 2 receptor α and β chain genes: Differentially regulated gene activity in response to mitogenic stimulation
Authors: Page Theresa H. , Dallman Margaret J.
Published: March 2007

We have isolated, by transient expression and screening using an oligonucleotide probe, cDNA clones encoding the rat interleukin 2 receptor (IL 2R) α and β chains, respectively. Both chains are approximately 60% identical at the amino acid level to their human counterparts. In common with the human and mouse IL 2R β chains, the rat β chain is a member of the cytokine receptor family. The rat IL 2R β chain contains no conventional signal transduction machinery and, like the mouse IL 2R β chain, has a significant number of deletions in its cytoplasmic tail in comparison to the human protein. Northern analysis indicates that the rat β chain message is constitutively transcribed in normal resting lymphocytes, whereas the α chain message is absent. Transcription of both chains of the receptor is up‐regulated by cellular activation. However, kinetic studies have shown that whereas α chain message is rapidly induced, and can be detected 5 h after the addition of phytohemagglutinin, levels of β chain mRNA increase at a much later time point and are not seen to rise until approximately 24 h after the addition of mitogen. These data suggest that the expression of high‐affinity IL 2R is controlled by factors which influence transcription of both the α and the β chain genes.
Expansion and high proliferate potential of the macrophage system throughout life time of lupus‐prone NZB/W and MRL lpr/lpr mice. Lack of down‐regulation of extramedullar macrophage proliferation in the postnatal period
Authors: Müller Meike , Emmendörffer Andreas , Lohmann‐Matthes Marie‐Luise
Published: March 2007

Systemic lupus erythematosus is an autoimmune disease, characterized by high liters of autoantibodies against many cell‐membrane and intracellular antigens. Polyclonal B cell activation and alterations in the T cell compartment have been described. The present report deals with the organ‐associated macrophage (MΦ) system of two lupus‐prone mouse strains (NZB/W and MRL lpr/lpr) and demonstrates that in both mouse strains the MΦ compartment of liver and spleen is clearly expanded. In the liver the number of F 4/80+ MΦ is strongly elevated. In addition, presence of early MΦ precursors and of extramedullary organassociated monocyte proliferation in response to colony‐stimulating factor (CSF) is documented in liver and spleen of these mice. Further, in normal animals during the first two weeks of life extramedullar monocytopoiesis is present in liver and spleen, which is then down‐regulated in the third week of life. In the two lupus‐prone mouse strains down‐regulation does not occur but extramedullar monocyte proliferation is sustained at high level throughout life time. As possible correlates for the expansion of the MΦ system elevated CSF‐1 mRNA levels are demonstrated in kidney, spleen and liver of NZB/W mice and elevated CSF serum levels are documented in MRL lpr/lpr mice. The possible contribution of the expanded MΦ system to B and T cell dysregulation is discussed.
Distinction of naive and memory BoCD4 lymphocytes in calves with a monoclonal antibody, CC76, to a restricted determinant of the bovine leukocyte‐common antigen, CD45
Authors: Howard Chris J. , Sopp Paul , Parsons Keith R. , McKeever Declan J. , Taracha Evans L N. , Jones Brenda V. , MacHugh Niall D. , Morrison W. Ivan
Published: March 2007

A murine IgG1 monoclonal antibody (mAb), CC76, has been produced that, based on findings of the relative molecular mass of polypeptides that it recognized, staining of leukocytes in blood and tissues, and the biological properties of the T lymphocyte subpopulations with which it reacts, is considered to identify an isoform of the leukocyte common antigen (LCA) family of molecules in cattle. The mAb is more similar to human CD45R which detect products requiring the presence of the B exon within the LCA gene and to the anti‐rat mAb MRC‐OX22, than to CD45RA or CD45RO. mAb CC76 reacts with an antigen expressed by subpopulations of cells in bovine blood that express BoCD2 and either the BoCD4 or BoCD8 antigens. T cells that express the γ/δ T cell receptor identified with mAb to BoWC1 antigen did not react with CC76. The molecule detected is expressed on B cells but not on monocytes or granulocytes. Only 2% of cells in thymic suspensions stained with mAb CC76. Immature cortical thymocytes that were BoCD1+ did not react with CC76 and 90% of the cells in thymic suspensions that were CC76+ had the phenotype of mature thymocytes. These cells were primarily in the medulla. The LCA isoform detected thus appears to be acquired by mature cells shortly before emigration from the thymic medulla into the periphery. Expression of the molecule detected by mAb CC76 on cells from lymph nodes was similar to that in blood, but expression on cells from the gut mucosa was quite different. Almost all, 95% and 93% respectively, of the BoCD4+ cells in the gut mucosa or discrete Peyer's patches were CC76−. A greater proportion of BoCD8+ cells from these sites, 35% and 26%, expressed the antigen.

Lymphocytes from animals that had been immunized with Trypanosoma brucei were sorted into BoCD4+, CC76+ and BoCD4+, CC76− populations and cultured in vitro with the variable surface glycoprotein antigen from the parasite. Lymphocyte transformation responses were entirely within the CC76− population indicating that the mAb distinguished naive from memory BoCD4+ T cells in cattle. Major histocompatibility complex (MHC) class I‐restricted cytotoxic precursor cells that expressed the BoCD8 antigen sorted from cattle that were immune to Theileria parva were both CC76+ and CC76− indicating that different isoforms of the LCA may be expressed on MHC class 1‐ and class II‐restricted memory cells and that BoCDS memory cells are heterogeneous with respect to the LCA isoform that they express.
Interleukin 4 receptor targeted cytotoxicity: Genetic construction and in vivo immunosuppressive activity of a diphtheria toxin‐related murine interleukin 4 fusion protein
Authors: Lakkis Fadi , Steele Alan , Pacheco‐Silva Alvaro , Rubin‐Kelley Vicki , Strom Terry B. , Murphy John R.
Published: March 2007

The interleukin 4 (IL 4) receptor is expressed on various cells of the immune system, including T and B lymphocytes, macrophages and mast cells. We have constructed a recombinant protein, DAB389‐mIL 4, that is composed of the enzymatically active and membrane translocation domains of diphtheria toxin fused to murine IL 4. We demonstrate that this fusion toxin selectively inhibits protein synsthesis in eukaryotic cells which express the murine IL 4 receptor. The cytotoxic potency of this fusion toxin is shown to be directly proportional to the reported number of IL 4 receptors on the surface of target cells. Since the action of DAB389‐mIL 4 can be blocked with either excess mIL 4 or antibody to mIL 4, we conclude that its entry into target cells is mediated through the mIL 4 receptor. A mutant form of DAB389‐mIL 4, DA(197)B389‐mIL 4, in which the fragment A‐associated ADP‐ribosyltransferase is inactive, is not cytotoxic to murine IL 4 receptor‐bearing cells. Finally, we demonstrate that DAB389‐mIL 4 administered subcutaneously to DBA/2 mice results in suppression of delayed‐type hypersensitivity (DTH); whereas, the non‐toxic DA(197)B389‐mIL 4 fails to dampen the DTH response.
Late treatment with anti‐LFA‐1 (CD11a) antibody prevents cerebral malaria in a mouse model
Authors: Falanga Pierre B. , Butcher Eugene C.
Published: March 2007

CBA/Ca mice injected with Plasmodium berghei develop cerebral malaria (CM) characterized by ataxia and progressive paralysis leading to death 7–9 days after experimental infection. The development of cerebral symptoms is a function of the immune response in susceptible strains, and depends on cell‐cell interactions involving T helper cells and mononuclear phagocytes. Here we ask whether antibodies to cell adhesion receptors of the immune system can influence the development of CM in this mouse model. When administrated on day 6 after infection, antibody to the leukocyte integrin leukocyte function‐antigen‐1 (LFA‐1) but not antibodies to MAC‐1, LECAM‐1 (the MEL‐14 antigen), α4 integrin or ICAM‐1 dramatically reduced the incidence of CM, leading to survival of most mice until the later onset of anemia. Anti‐LFA‐1 treatment did not result in a substantial decrease in the monocyte accumulation observed in cerebral vessels of susceptible mice. Its efficacy may be related to the broader roles of LFA‐1 in cell‐cell interactions important in the later pathogenic stages of the immune response to the parasite. Perturbation of immune cell function through interference with cell adhesion mechanisms may offer an important therapeutic tool in acute, life‐threatening immune‐mediated disorders.
CD4+CD8+CD3high thymocytes appear transiently during ontogeny: evidence from phenotypic and functional studies
Authors: Hugo Patrice , Boyd Richard L. , Waanders Gary A. , Scollay Roland
Published: March 2007

During T cell development thymocyte subsets emerge in a defined order, reflective of their maturational stage. In this study we determined the timing of appearance of CD4+CD8+CD3high thymocytes during in vivo and in vitro embryonic development, and thymic reconstitution after cortisone treatment. In these models, CD4+CD8+CD3high cells followed CD4+CD8+CD3low and preceded mature CD4+CD8+CD3high/CD4+CD8+CD3high thymocytes, while cortisone resistance was first seen among CD4+CD8+CD3high cells. CD4+CD8+CD3high thymocytes were also shown to display a pattern of antigen receptor‐mediated calcium influx intermediate between that induced in other CD4+CD8+ cells and mature thymocytes. These results are consistent with a precursor‐progeny relationship between CD4+CD8+CD3low and CD4+CD8+CD3high thymocytes, the latter developing to mature thymocytes (Hugo, P. et al., Int. Immunol. 1991. 3: 265).
Effect of ubiquitin on platelet functions: possible identity with platelet activity suppressive lymphokine (PASL)
Authors: Pancré Véronique , Pierce Raymond J. , Fournier Franck , Mehtali Majid , Delanoye Anne , Capron André , Auriault Claude
Published: March 2007

In an attempt to clone a suppressive lymphokine of platelet function (PASL), we have obtained a cDNA clone coding for the previously described human ubiquitin‐80 amino acid fusion protein. Our clone differs from the described sequence in that it contains the complete amino acid sequence of ubiquitin as well as a short (25 bp) 5′ noncoding region. In addition the 3′ untranslated region is slightly longer than that previously shown. Like PASL, purified ubiquitin can inhibit the cytotoxic properties of platelets and the production of oxygen metabolites by these cells. Moreover, this molecule is able to act as a proaggregating factor and seems of a great interest in pathologies involving defects in platelet aggregation. Ubiquitin could also have a potential use in the regulation of immunological disorders in which platelets seem to be implicated such as hymenoptera venom hypersensitivity and aspirin‐sensitive asthma, since in both situations, ubiquitin is able, as is PASL, to inhibit the cytotoxic function of platelets. Indeed ubiquitin possesses important pharmacological potentialities which have not been previously described. This molecule and PASL share several similarities in their functional and physicochemical properties. PASL could therefore belong to the family of ubiquitins.
In vivo induction of γ/δ T cells with highly potent and selective anti‐tumor cytotoxicity
Authors: Ericsson Per‐Olof , Hansson Johan , Widegren Bengt , Dohlsten Mikael , Sjögren Hans‐Olov , Hedlund Gunnar
Published: March 2007

High frequencies of CD5+TcR α/β− T cells were induced in the peritoneal cavity of rats immunized with syngeneic W439 lymphoma cells. These TcR α/β− cells expressed TcR δ mRNA as analyzed by the polymerase chain reaction technique. The δ+ (TcR γ/δ+) T cells were of the CD2+, CD3+, CD4−, CD8+, CD45RB+ phenotype and showed stronger anti‐tumor cytotoxicity compared to the TcR α/β+ T cells. The cytotoxic effects of both α/β and γ/δ T cells were selective for the W439 lymphoma cells and were not directed to other syngeneic tumors, natural killer targets and syngeneic or allogeneic normal cells. T cells, including both α/β and γ/δ cells, were induced when WF rats were immunized with allogeneic BN spleen cells. In this case the γ/δ T cells showed allo‐selective cytotoxicity, although weaker compared to the TcR α/β+ T cells. The γ/δ T cells, induced by immunization with either W439 cells or BN spleen cells, were selective for the immunogen used and had no effect on irrelevant target cells, indicating that these effector cells were not activated by a shared γ/δ T cell‐related superantigen. Since highly potent tumor‐selective γ/δ cytotoxic T lymphocytes could be induced by syngeneic lymphoma cells, we suggest a role for γ/δ T cells in the defense against certain types of tumors.
The use of the polymerase chain reaction to map CD4+ T cell epitopes
Authors: Nakagawa Terry Y. , Grafenstein Hermann Von , Sears Jonathan E. , Williams John , Janeway Charles A. , Flavell Richard A.
Published: March 2007

CD4+ T cells recognize processed exogenous antigen in the form of peptides bound to syngeneic major histocompatibility complex class II molecules on antigen‐presenting cells. We have developed a novel and convenient method to synthesize and map CD4+ T cell epitopes of cloned antigens using polymerase chain reaction (PCR)‐directed construction of genes expressing recombinant protein fragments. Unique restriction sites incorporated into the PCR primers were employed for the unidirectional cloning of gene fragments into a bacterial expression vector that can be induced to high‐level expression. The bacterial lysate could be used directly in T cell proliferation assays. Overlapping recombinant fragments spanning the entire protein were generated and tested. The length of the sequence containing the epitope was further reduced by utilizing PCR to generate 3′ truncations. Finally, a small number of overlapping peptides spanning a sequence of 39 amino acids were synthesized to identify a thirteen‐amino acid peptide epitope within chicken transferrin that stimulates the T helper cell clone D10.G4.1. PCR‐directed construction of fragments of antigen allows for optimal design of strategies for the mapping and analysis of CD4+ T cell epitopes.
Activation of the CD3/T cell receptor (TcR) complex or of protein kinase C potentiate adenylyl cyclase stimulation in a tumoral T cell line: involvement of two distinct intracellular pathways
Authors: Bihoreau Claire , Heurtier Agnès , Enjalbert Alain , Corvaïa Nicole , Bensussan Armand , Degos Laurent , Kordon Claude
Published: March 2007

A monoclonal antibody (OKT3) directed against the T cell receptor (TcR)/CD3 molecular complex, as well as a protein kinase C (PKC) activator (phorbol 12‐myristate 13‐acetate, PMA) were added to a culture of tumoral Jurkat T cells, in order to precise the sequence of intracellular signals leading to T cell activation. The experiments were performed in the presence or in absence of various stimulators of adenylate cyclase (AC) such as forskolin (FK), cholera toxin (CT) or prostaglandin E2 (PGE2). OKT3 increased inositol phosphate (IP) production; in parallel, it induced a slight accumulation of cAMP. The effect was markedly potentiated in presence of FK or CT, and to a lesser extent in the presence of PGE2. FK stimulated adenylate cyclase of Jurkat cell membranes, but the effect was not potentiated by OKT3, suggesting that potentiation of cAMP accumulation requires intact cells and is not mediated by direct receptor coupling. On the other hand, elevated cAMP accumulation induced a negative feedback on IP production. The effect of OKT3 on cAMP was mimicked by A23187, a Ca2+ ionophore, and abolished in the absence of extracellular Ca2+. PMA had the same effect as OKT3 on basal or FK‐ and CT‐induced accumulation of cAMP. In contrast, it inhibited the PGE2 effect on the cyclic nucleotide. After desensitization of PKC by pretreatment with a high concentration of PMA, the phorbol ester was no longer effective. Under those conditions, facilitation by OKT3 of FK‐induced accumulation of cAMP was preserved, whereas potentiation by the monoclonal antibody of the PGE2 stimulation of AC was even enhanced. The data indicate that cAMP accumulation indirectly elicited by phospholipase C activation is, at least partly, mediated by IP‐dependent Ca2+ mobilization, while PKC is preferentially effective as an inhibitor of PGE2 stimulation.
Recombinant soluble tumor necrosis factor receptor proteins protect mice from lipopolysaccharide‐induced lethality
Authors: Lesslauer Werner , Tabuchi Hisahiro , Gentz Reiner , Brockhaus Manfred , Schlaeger Ernst Juergen , Grau Georges , Piguet Pierre Francois , Pointaire Pascal , Vassalli Pierre , Loetscher Hunsruedi
Published: March 2007

The in vivo efficacy of human recombinant soluble tumor necrosis factor (TNF) receptor protein to prevent and to treat lipopolysaccharide (LPS)‐induced lethal toxicity in D‐galactosamine‐treated mice was investigated. Chimeric proteins of the receptor extracellular domains fused to the hinge region of human IgG3 were expressed in myeloma cells (rsTNFR‐hγ3). The fusion proteins had a disulfide‐bonded dimeric structure. Upon intravenous injection, their serum concentration decreased relatively slowly after an initial phase of rapid elimination. D‐galactosamine‐sensitized mice were fully protected from the toxic effects of LPS, if the animal were pretreated with rsTNFR‐hγ3 at 20 μg/animal. Partial protection was seen at significantly lower doses and when rsTNFR‐hγ3 was given up to 3 h after LPS.
Therapy against murine collagen‐induced arthritis with T cell receptor Vβ‐specific antibodies
Authors: Chiocchia Gilles , Boissier Marie‐Christophe , Fournier Catherine
Published: March 2007

Immunization with native type II collagen (CII) of susceptible strains of mice (H‐2q) induces a rheumatoid arthritis‐like disease. Collagen‐induced arthritis (CIA) is an experimental model for T cell‐mediated autoimmune disease. To investigate the T cell receptor (TcR) repertoire involved in the pathogenesis of CIA, CII‐primed DBA/1 mice were treated with various TcR VbT‐specific monoclonal antibodies (mAb) using a protocol resulting in a long‐term elimination of the target T cells. In vivo treatment with anti‐CD4 mAb led to nearly complete protection against CIA. Mice injected with anti‐Vβ8.1,2 or anti‐Vβ5.1,2 mAb had a reduced incidence of arthritis (respectively 28.6% and 50% vs 84.6% for the control group). Administration of anti‐VbT2 mAb delayed the onset of the disease whereas injection of anti‐VbT6 or anti‐VbT11 mAb did not alter CIA. Moreover, the combined treatment with anti‐VbT2 and anti‐Vβ5 mAb efficiently reduced the development of CIA. The humoral response to CII was down‐regulated only in the groups of mice that were improved by the treatment. In vitro proliferative response to CII of lymph node cells from primed DBA/1 was partially blocked by addition of several anti‐VbT mAb. Thus, our findings suggest that the overall T cell response to CII may be polyclonal while the T cell clones involved in the pathogenesis of CIA express a limited number of Vβ chains.
Direct interaction with primed CD4+ CD45R0+ memory T lymphocytes induces expression of endothelial leukocyte adhesion molecule‐1 and vascular cell adhesion molecule‐1 on the surface of vascular endothelial cells
Authors: Damle Nitin K. , Eberhardt Chris , Van Der Vieren Monica
Published: March 2007

The process of recruitment of leukocytes at sites of inflammation involves direct cell‐to‐cell interactions between leukocytes and vascular endothelial cells (EC) mediated by various adhesion receptors on leukocytes and their inducible endothelial ligands. In this study we have examined the induction on EC of endothelial leukocyte adhesion molecule‐1 (ELAM‐1), intercellular adhesion molecule‐1 (ICAM‐1), and vascular cell adhesion molecule‐1 (VCAM‐1) upon their interaction with subpopulations of human T cells. When co‐cultured with EC both resting CD4+ T and CD8+ T cells caused a modest increase in the expression of endothelial ICAM‐1. Moreover, resting CD4+ but not CD8+ T cells induced expression of ELAM‐1 and VCAM‐1 on a small fraction of unstimulated EC. Prior activation with phorbol 12‐myristate 13‐acetate (PMA) significantly increased the ability of T cells to up‐regulate endothelial ICAM‐1 and also induced the expression of both ELAM‐1 and VCAM‐1. PMA‐primed CD4+ T cells induced both VCAM‐1 and ELAM‐1 on EC more efficiently than CD8+ T cells. Furthermore, the ability to induce the expression of ELAM‐1 and VCAM‐1 was confined to the CD4+CD45R0+ memory/primed subpopulation of T cells. This induction of various endothelial adhesion ligands could also be mediated by antigen‐primed CD4+ T cell lines. The CD4+ T cell‐mediated induction of adhesion ligands required direct intercellular contact with EC because neither cultures of EC and PMA‐primed CD4+ T cells separated by a microporous membrane insert nor the conditioned medium of PMA‐primed T cells induced expression of ELAM‐1 and VCAM‐1 on EC. Cyclosporin A significantly inhibited the activation of T cells with PMA but had no effect on the ability of PMA‐primed T cells to up‐regulate endothelial CAM. Thus, CD4+CD45R0+ T cells via as yet unknown mechanism can significantly enhance the expression of each of the three endothelial adhesion ligands and, thereby, may facilitate the process of recruitment of additional leukocytes to exacerbate inflammation.
Environmental and allele‐specific influences on T cell receptor gene rearrangement: skewed α, δ and γ gene rearrangement patterns in chimeric mice
Authors: Larché Mark , Manzo Andrea R. , Hurwitz Julia L.
Published: March 2007

This study was performed as a means to examine the effects of environment and stem cell origin on the molding of T cell receptor gene rearrangements during T cell development. Lethally irradiated adult mice were first reconstituted with (C57BL/6 x DBA/2)F1 stem cells, which derived either from a fetal liver or adult bone marrow source. The gene rearrangements in the irradiated thymi were then compared to those in normal fetal or adult thymi by hybridoma analysis. Results showed a general absence of gene rearrangements typical of the normal fetal thymus in both sets of chimeras, α and γ gene rearrangements in chimeric mice matched normal adult patterns. However, chimeric thymocytes were unique in an unusually low frequency of rearrangements at the δ locus. The use of the bone marrow vs. fetal liver as stem cell sources in chimeric mice did not affect the patterns, indicating that environmental factors played a major role in the molding of gene rearrangement at multiple T cell receptor loci. Interestingly, the chromosomal sequence added an additional influence as homologous chromosomes showed allele‐specific rearrangement patterns. We now question whether the unique patterns of rearrangement in irradiated adult thymi may substantially affect developing T cell populations in chimeric animals, particularly with regard to the γ/δ T cell subset. Further analyses are warranted, both in experimental and clinical settings, regarding ultimate potentials for T cell diversity and function in transplantation recipients.
An abnormal signal transduction pathway in CD4−CD8− double‐negative lymph node cells of MRL lpr/lpr mice
Authors: Yokoyama Kazushige , Gachelin Gabriel
Published: March 2007

We describe here a novel 26‐kDa posphoprotein (p26), associated to the T cell receptor of CD4−CD8− lymph node cells of lpr/lpr mice, but not present in significant amounts in control mouse cells including polyclonally activated T cells. lpr p26 is constitutively phosphorylated on a tyrosyl residue. It is most likely a member of the G protein family and displays high GTP‐binding and GTPase activities both unsensitive to interleukin 2. Bordetella pertussis toxin has no effect on the spontaneously enhanced GTP hydrolysis. The traits associated to p26 could contribute to the distinctive features of lpr/lpr double‐negative cells.
Down‐regulation by tumor necrosis factor‐α of neutrophil cell surface expression of the sialophorin CD43 and the hyaluronate receptor CD44 through a proteolytic mechanism
Authors: Campanero Miguel R. , Pulido Rafael , Alonso Jose L. , Pivel Juan P. , Pimentel‐Muiños Felipe X. , Fresno Manuel , Sánchez‐Madrid Francisco
Published: March 2007

Adhesion of human neutrophils to endothelial cells is a crucial step during migration to the extravascular sites of inflammation. A large number of molecules, including the CD44 and LAM‐1 antigens, have been described to participate in this process. We have investigated the regulation by human recombinant tumor necrosis factor‐α (TNF‐α) of human neutrophil plasma membrane expression of both CD44 and LAM‐1 adhesion molecules, as well as that of CD43 sialophorin, which has been involved in adhesion and activation of leukocytes. The expression of these three antigens was down‐regulated in neutrophils upon TNF‐α treatment, as determimned by immunofluorescence and immunoprecipitation expriments. However, the expression of other cell surface molecules, such as CD45 or CD11b, was up‐regulated. Similar regulatory effects were also observed upon neutrophil treatment with other activating agents such as the chemoattractant peptide formyl‐Met‐Leu‐Phe, the calcium ionophore A23187, or the phorbol ester phorbol 12‐myristate 13‐acetate. Protease inhibitors virtually abrogated the TNF‐α‐induced down‐regulation of CD43 and CD44 expression, but not that of LAM‐1, suggesting the involvement of a protease activity in this process. These results underline the role of TNF‐α on the differential regulation of cell surface expression of neutrophil adhesion molecules, thus implying modifications in the neutrophil adhesive properties.
Prolonged survival of skin grafts following treatment with an antibody to a putative cell triggering molecule, QCA‐1
Authors: Aspinall Richard , Kampinga Jaap , Van Den Bogaerde Johan
Published: March 2007

The QCA‐1 molecule (quiescent cell antigen‐1) appears to be involved in the differentiation events undergone by T cell following occupancy of the antigen receptor. Here we show that modulation of the QCA‐1 antigen from the surface of the cell normally follows activation, and that treatment of animals with the antibodies against the QCA‐1 molecule inhibits the normal response to an allograft without appearing to alter the number of peripheral T cells or the expression by these cells of the α/β T cell antigen receptor.
Differential responses to interleukin 2 define functionally distinct subsets of human natural killer cells
Authors: Baume Daniel M. , Robertson Michael J. , Levine Herbert , Manley Thomas J. , Schow Peter W. , Ritz Jerome
Published: March 2007

Human natural killer (NK) cells can be subdivided into two populations based on the density of cell surface CD56 antigen. The great majority (∼ 90%) of NK cells express CD56 at low levels (the CD56dim phenotype), whereas a small NK cell subset (∼ 10%) exhibits approximately fivefold greater density of surface CD56. Exposure to exogenous interleukin 2 (IL 2) induces tenfold greater proliferation of CD56bright cells compared to CD56dim lymphocytes, even though both subsets constitutively express similar levels of intermediate affinity IL 2 receptor (IL 2R) p75 chains. Incubation with IL 2 alone or irradiated target cells alone could induce expression of the IL 2R p55 chain by both CD56bright and CD56dim NK cells; a combination of both stimuli was most effective. IL 2R p55 induction was evident after co‐culture of NK cells with both NK‐sensitive and NK‐resistant cell lines or with antibody‐coated target cells. Activation of NK cells with IL 2 plus target cells resulted in enhanced proliferation compared to activation with IL 2 alone; target cells alone did not induce significant proliferation. Although both NK cell subsets appeared to express high‐affinity IL 2R p75/p55 heterodimers after stimulation with target cells and IL 2, proliferation of CD56dim cells remained minimal after such activation; activated CD56dim cells consistently demonstrated less proliferation to IL 2 than did resting CD56bright cells. In contrast, CD56bright NK cells exhibited even greater proliferation after stimulation with target cells. Almost all CD56dim NK cells expressed CD16 (FcγR III) as well as the NK ζ chain, whereas <50% of CD56bright cells express either CD16 or ζ. CD56bright and CD56dim lymphocytes, thus, appear to represent distinct subpopulations of NK cells with different functional activities. Unlike CD56bright cells, CD56dim NK cells do not proliferate optimally to IL 2, even after the latter have been stimulated to express both IL 2R p55 and IL 2R p75. Efficient proliferation of CD56dim NK cells may, thus, require additional or alternative signals.
Intestinal intraepithelial lymphocyte T cells are resistant to Ipr gene‐induced T cell abnormalities
Authors: Aicher Wilhelm K. , Fujihashi Kohtaro , Taguchi Takashi , McGhee Jerry R. , Yamamoto Masafumi , Eldridge John H. , Gay Steffen , Kiyono Hiroshi
Published: March 2007

The mucosal immune system of the gastrointestinal (GI) tract consists of Peyer's patches (PP), which are IgA inductive sites, and more diffuse effector regions which include cells in the intraepithelial lymphocyte (IEL) compartment. Since autoimmune MRL lpr/lpr (MRL/lpr) mice develop a proliferating CD3+, CD4−, CD8− (double negative; DN), B220+ T cell subset in systemic lymphoid tissue, we have initiated studies to determine the distribution of CD3+, DN, B220+ T cells (B220+ T cells or lpr/lpr T cells) in the GI immune system. Specifically, we examined T cell subsets separated according to expression of CD4, CD8, Thy‐1, B220, α/β T cell receptor (TcR) and γ/δ TcR in PP and IEL of MRL/lpr mice at 6, 12 and 21 weeks of age. Increased numbers of CD3+ T cells were noted in both PP and spleen of 12‐ and 21‐week‐old mice in which the development of autoimmune disorders were also evident. However, normal numbers of CD3+ IEL T cells were seen in MRL/lpr mice in all three age groups tested. When the presence of T cell lymphadenopathy was examined in both IgA inductive and effector tissues, the PP followed the B220+ T cell pattern seen in the spleen, where ∼ 30%‐50% of CD3+ T cells in the PP of 12‐ and 21‐week‐old MRL/lpr mice expressed the phenotype of lpr/lpr T cells and >90% were α/β TcR+. On the other hand, B220+ T cells had not developed in PP or spleen of 6‐week‐old MRL/lpr mice. Of interest was the finding that IEL from lpr/lpr homozygous mice did not contain B220+ T cells in any age group tested. In this regard, the IEL of MRL/lpr mice comprised an identical pattern and frequency of CD4−/CD8−, CD4+/CD8−, DN and CD4+/CD8+ (double positive, DP) T cell subsets as their normal counterparts (i.e. MRL +/+, BALB/c and C3H/HeN mice) which consisted of ∼75%, ∼7.5%, ∼7.5% and ∼10%, respectively. Further, Thy‐1, γ/λ TcR and α/β TcR expression in these four subsets of MRL/lpr IEL were very similar to normal mice. These results suggest that the intestinal IEL compartment is minimally affected by the lpr/lpr mutation which induces T cell abnormalities and indicate that B220+ T cells do not preferentially home to IEL. Further, our results support the concept that IEL T cells develop as a separate T cell lineage from thymus‐derived cells.
ICAM‐1‐independent lymphocyte transmigration across high endothelium : Differential up‐regulation by interferon γ, tumor necrosis factor‐α and interleukin 1β
Authors: May Michael J. , Ager Ann
Published: March 2007

The adhesion of lymphocytes to cytokine‐treated high endothelium was studied using cultured high endothelial cells (HEC). Pretreatment of the HEC layer with a variety of cytokines caused up‐regulation of lymphocyte adhesion with the effects ordered interferon γ (IFN‐γ) > tumor necrosis factor‐α (TNF‐α) ⩾ interleukin 1β (IL 1β). Increased lymphocyte adhesion was found to be independent of ICAM‐1 as expression by HEC was not increased by cytokines and antibodies against ICAM‐1 did not block adhesion. The peptide CS1 and anti‐β1 integrin subunit antibodies, however, caused partial inhibition of lymphocyte adhesion thus indicating a role for fibronectin on HEC and α1β1 on lymphocytes. Study of the kinetics of lymphocyte adhesion showed that the effects of IFN‐γ and TNF‐α were persistent and remained detectable 2.5 h after removal of the cytokines whereas the effects of IL 1β were transient and were not sustained beyond 1 h. All of the cytokines used caused transient increases in the number of surface‐bound lymphocytes with IFN‐γ > TNF‐α ⩾ IL 1β, however, the most dramatic effect was on the transmigration of lymphocytes across the HEC. Both IFN‐γ and TNF‐α caused sustained increased transmigration with IFN‐γ having the greater effect. IL 1β had little effect on transmigration. This model demonstrates that the binding and transmigration of lymphocytes across HEC can be differentially regulated by the actions of individual cytokines. These results support the concept that locally produced cytokines regulate HEC function within the lymph node.
The human cord blood antibody repertoire. Frequent usage of the VH7 gene family
Authors: Mortari Frank , Newton J. Allen , Wang Jin Yi , Schroeder Harry W.
Published: March 2007

We have previously demonstrated a consistent preferential usage of a small set of VH, DH and JH gene segments in second‐trimester fetal liver. To examine the extent of heavy chain repertoire diversification in newborns, we generated an unrestricted cDNA library from cord blood mononuclear cells and sequenced the variable domains of randomly isolated Cμ+ transcripts. We found this set of transcripts to be enriched for JH4, 5 and 6, whereas previously reported fetal transcripts preferentially expressed JH3 and 4. The cord blood transcripts used a number of different DH gene segments, whereas fetal transcripts were enriched for DHQ52. Of the thirteen cord blood sequenced, three were members of the newly described VH7 family which to date has not been detected in fetal liver. Indeed, only one of the isolated VH gene segments had been previously observed in fetal transcripts. As a result of enhanced N‐region addition and use of longer DH and JH gene segments, both the sequence diversity and range of potential antigen‐binding structures of cord blood complementarity‐determining region 3 domains was vastly expanded. Thus, the repertoire bias evident in fetal liver was no longer apparent in this more mature population of cord blood B cells.
A major human thyroglobulin epitope defined with monoclonal antibodies is mainly recognized by human autoantibodies
Authors: Henry Mireille , Zanelli Eric , Piechaczyk Martine , Pau Bernard , Malthièry Yves
Published: March 2007

The antigenic nature of 15 anti‐human thyroglobulin (hTg) monoclonal antibody (mAb) epitopes was studied by two different approaches. First, we tested two successive protease‐digest products of hTg. Only four mAb from the same cluster of reactivity recognized a low‐molecular weight peptide, the other mAb only bound native hTg or high‐molecular weight digest fractions. Second, these 15 mAb were used to immunoscreen hTg expression libraries. Only the same four mAb revealed immunoreactive clones corresponding to region 1149–1295 on the hTg primary sequence. After subcloning, this antigenic determinant was reduced to a 102‐amino acid peptide (hTg region 1149–1250). The two different methodologies were coherent and complementary, and demonstrated that hTg sequence 1149‐1250 is the target for this cluster of four mAb. Moreover, anti‐hTg autoantibodies which cross‐reacted with these mAb bound the 102‐amino acid peptide. This epitope was the one most frequently detected by sera from autoimmune thyroid disease. The data confirm the presence of an immunodom‐inant domain in the central part of the hTg molecule and suggest that this mAb epitope may be a powerful probe for the diagnosis of autoimmune thyroid disorders.
Cyclosporin A can switch the immune response induced by antigen from a humoral to a cell‐mediated mode
Authors: Bretscher Peter A. , Havele Calliopi
Published: March 2007

Cyclosporin A (CsA) is known as a nontoxic inhibitor of the immune response that is primarily employed in humans to prevent the rejection of allografts. We report here on a novel activity for this drug as an immunomodulator. CsA can either inhibit or facilitate the induction of delayed‐type hypersensitivity (DTH) depending on the class of immune response that would be induced in the absence of the drug. The drug inhibits the in vivo and in vitro induction of DTH when antigen is given under conditions that normally result in the induction of this response. The same concentration or dose of CsA inhibits the in vitro and in vivo induction of an antibody response and the antigen induces DTH instead. An explanation for these different effects of CsA on the induction of DTH is proposed. This novel activity of CsA in modulating the immune response from an antibody to a cell‐mediated mode may have clinical applications.
Isoform‐specific associations of CD45 with accessory molecules in human T lymphocytes
Authors: Dianzani Umberto , Redoglia Valter , Malavasi Fabio , Bragardo Manuela , Pileri Alessandro , Janeway Charles A. , Bottomly Kim
Published: March 2007

Association of CD45 with surface molecules was investigated in human T lymphocytes by co‐capping. CD45 appeared to be associated with the CD3/T cell receptor complex and with CD4 or CD8 molecules in memory, but not in naive T cells, as previously reported in the mouse. Associations of CD45 isoforms with accessory molecules were then identified with seven anti‐CD45R monoclonal antibodies (mAb). An isoform‐specific association pattern was observed: CD2 co‐capped with CD45 molecules recognized by UCHL1 mAb (CD45R0), LFA‐1 with molecules bound by 2H4 mAb (CD45RA). and both CD4 and CD8 with molecules reacting with MCA. 347 mAb (whose isoform specificity was not known). Further information on the CD45 isoform(s) associated to CD4 and CD8 was sought by assessing the isoform specificity of MCA. 347. Cross‐competition experiments showed that it reacts with an epitope clearly different from those recognized by 2H4 and UCHL1, and only partially overlapping the PD7/26 epitope (CD45RB). Moreover, the competition between MCA. 347 and PD7/26 was maximal in naive T cells and minimal both in memory T cells and in a subset expressing CD11b, a marker of granular lymphocytes. Immunoprecipitation experiments showed that MCA. 347 binds to CD45 molecules with a molecular mass of 220, 205 and 190 kDa, the 190‐kDa molecules not being recognized by 2H4, PD7/26 or UCHL1. These data indicate that MCA. 347 recognizes amino acid sequences different from those coded by the exon A or B of the gene, and not expressed by CD45RO, suggesting that it binds to sequences coded by the exon C. In conclusion, this work shows that in human T cells different CD45 isoforms are associated to different surface molecules: LFA‐1 is associated to CD45RA, CD2 to CD45RO and CD4 and CD8 presumably to CD45RC. This peculiar behavior of CD45 suggests that it may play a crucial role in lymphocyte activation, probably by modulating the signals delivered to the cell by different receptor systems.
Preferential association of α and β chains of the T cell antigen receptor
Authors: Uematsu Yasushi
Published: March 2007

The cytotoxic T lymphocyte (CTL) clone B6.2.16 expresses a Vβ8.2/Jβ2.3/Cβ2‐encoded T cell receptor (TcR) β chain and an α chain that is encoded by a novel Vα gene segment, Jα27 and Cα. While expression of VαB6.2.16 and Jα27 is not detectable in lymph node cells of normal C57BL/6 mice, expression of these gene segments was readily seen in transgenic mice expressing the rearranged β chain gene of the B6.2.16 T cell clone. This finding indicates that only a limited number of α chains can associate with the B6.2.16 β chain and strongly suggests that the size of the TcR repertoire of mature T cells is not only limited by TcR ligand‐mediated thymic selection but also by restrictions in α‐β combinatorial chain association.
Vβ repertoire in rats and implications for endogenous superantigens
Authors: Smith Lawrence R. , Kono Dwight H. , Kammuller Michael E. , Balderas Robert S. , Theofilopoulos Argyrios N.
Published: March 2007

Endogenous superantigens of mice, encoded by mammary tumor virus proviral integrants, induce intrathymic deletion of entire T cell populations that express specific Vβ gene products, a phenomenon proposed to be important in self‐tolerance and prevention of toxic responses to exogenous microbial superantigens. Evidence for the presence of Vβ selecting/deleting endogenous superantigens in other species is lacking. We report here that rats do not exhibit endogenous superantigen‐induced Vβ clonal deletions despite their strong response to bacterial superantigens. These findings indicate that endogenous superantigens are not obligatory in Vβ repertoire shaping.
Ly‐1 B (B‐1) cells are the main source of B cell‐derived interleukin 10
Authors: O'garra Anne , Chang Ray , Go Ning , Hastings Robin , Haughton Geoffrey , Howard Maureen
Published: March 2007

We have previously reported (O'Garra, A. et al., Int. Immunol. 1990. 2: 821) that murine B lymphomas and purified normal peritoneal B cells produce interleukin (IL) 10. We now show that this production of IL 10 B cells correlates with the presence of Ly‐1 (B‐1) B cells, in both normal and diseased mice. Using a semi‐quantitative modification of the polymerase chain reaction, we show that IL 10 expression is detectable in peritoneal B cells but only becomes apparent in splenic B cells of aged mice of which a high proportion are Ly‐1+. Furthermore, the expression of IL 10 is constitutive in splenic B cells from mice carrying the Ly‐1+ BCL1 lymphoma. Since IL 10 is a potent regulator of in vitro immune function, its production by Ly‐1 lineage B (B‐1) cells raises the possibility that this subset of B cells may regulate their own development and/or the function of other immunocompetent cells.
Tissue‐specific migration pathways by phenotypically distinct subpopulations of memory T cells
Authors: Mackay Charles R. , Marston Wendy L. , Dudler Lisbeth , Spertini Olivier , Tedder Thomas F. , Hein Wayne R.
Published: March 2007

A proportion of T cells recirculate in a tissue‐selective manner. Recent studies which showed that the skin‐tropic subset of T cells was of memory/activated type, led us to examine whether the preferential homing of T cells to the gut also involved memory T cells, and if so whether these memory T cells were phenotypically distinct from other memory T cells. Lymphocytes migrating through the gut and the skin of sheep was collected by cannulating the lymphatic ducts draining these tissues. Both naive and memory T cells were found to recirculate through the gut, although only memory T cells migrated through the skin. However, when T cells from the gut were labeled with fluorescein isothiocyanate and assessed for their migration back to the gut, it was the memory population which showed a tropism for the gut. Gut‐tropic memory T cells migrated poorly through the skin, indicating that these cells were distinct from skin‐tropic memory T cells. This was confirmed by phenotypic analysis. Gut memory T cells expressed very low levels of the α6 and β1 integrins, in contrast to skin memory T cells which expressed high levels. There was no evidence for heterogeneity within the naive T cell population, which migrated preferentially to lymph nodes. This migration pattern could be explained in part by the high expression of the L‐selectin (lymph node homing receptor, LAM‐1) on naive T cells, in contrast to memory T cells from gut or skin which were mostly L‐selectin negative. These results in sheep indicate that subsets of α/β memory T cells show tissue‐selective migration patterns, which probably develop in a particular environment following encounter with antigen.
Memory T lymphocyte hyporesponsiveness to non‐cognate stimuli: a key factor in age‐related immunodeficiency
Authors: Flurkey Kevin , Stadecker Miguel , Miller Richard A.
Published: March 2007

Previous studies from our laboratory have suggested that aging leads to an accumulation of cells expressing high levels of CD44, thought to be a marker for memory lymphocytes, and that positively selected CD44hi T cells, from mice of any age, respond poorly to concanavalin A (Con A) in limiting dilution estimates of interleukin (IL)‐2‐producing cells. We now report the results of a more comprehensive analysis of memory T cell function, in old and young mice, to non‐cognate activators (Con A and the staphylococcal enterotoxin SEB). We report that memory T cells, isolated by removing cells bearing the CD45RB determinant, contain very few cells able to respond to either Con A or SEB under limiting dilution culture conditions, whether the responses are measured by IL‐2 or by IL‐3 accumulation. As a control, we show that memory T cells do respond strongly, at limiting dilution, to recently encountered priming antigens, i.e. Schistosoma mansoni egg antigen; the limiting dilution culture protocol thus does not preclude activation of memory T cells when cognate stimuli are presented to antigen‐specific cells. These data suggest that virgin and memory T cells may differ fundamentally in their activation requirements, and suggest further that the accumulation, with age, of memory T cells accounts for the low responsiveness of old mice to non‐cognate mitogens.
Induction of experimental autoimmune uveoretinitis in Lewis rats with purified recombinant human retinal S‐antigen fusion protein
Authors: Roberts Andrew J. , Kasp Eva , Stanford Miles , Dumonde Dudley C. , Paul Banga J.
Published: March 2007

Full‐length human retinal cDNA for S antigen (S‐ag) and for the α subunit of transducin (α‐Td) were subcloned into a bacterial expression plasmid vector to generate recombinant fusion proteins with glutathione‐S‐transferase (GST). The recombinant GST‐S‐ag and rGST‐α‐Td fusion proteins were purified from bacterial extracts by continuous flow preparative gel electrophoresis under denaturing conditions, and were assessed for their ability to induce experimental autoimmune uveoretinitis (EAU). Immunization of Lewis rats with single doses of 10 μg‐100 μg rGST‐S‐ag in Freund's complete adjuvant supplemented with Bordetella pertussis readily induced clinical signs of EAU. Immunization with GST alone did not induce EAU indicating that disease activity was ascribable to the S‐ag residues in the fusion protein. Although the α‐Td shares limited sequence homology with S‐ag, the rGST‐α‐Td fusion protein was also not uveitogenic in Lewis rats. The clinical severity of EAU in Lewis rats sensitized with rGST‐S‐ag was found to be milder than that induced with native S‐ag preparations purified from human retina. However, humoral antibody responses to sensitization with the recombinant S‐ag fusion protein were of a higher magnitude than with native S‐ag. The availability of recombinant preparations of human S‐ag protein will be of value in studying its processing and presentation to T cells derived from patients with autoimmune retinal vasculitis.