bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential expression of the T cell receptor/CD3 genes and their lymphoid‐specific transcription factor genes in murine T cell x fibroblast and T cell x B cell hybrids
Authors: Yamada Toshiyuki , Hitomi Yoshiaki , Satake Masanobu , Oikawa Tsuneyuki
Published: March 2007

We generated cell hybrids between mouse T cell lymphoma EL4 cells and mouse fibroblast B82 cells (BELIII and BELIV) to examine the expression of T cell receptor (TcR)/CD3 genes and their lymphoid‐specific transcription factor genes, which are normally detected in EL4 cells. In BELIII and BELIV, expression of the TcRα, TcRβ and CD3δ genes was extinguished, whereas expression of the CD3ϵ gene was still detected. Expression of the (lymphoid enhancer binding factor 1) LEF‐1 gene was extinguished and that of the GATA‐3 gene was hardly detected in BELIII and BELIV. Ets‐1 gene expression, observed not only in EL4 cells but also in B82 cells, was considerably reduced in BELIII and BELIV. A much higher level of PEBP2αA gene expression was observed in B82 cells than in EL4 cells and was preserved in BELIII and BELIV. To examine whether reduced expression of these genes is also found in T cell x B cell hybrids, we generated an additional cell hybrid between EL4 cells and mouse plasmacytoma S194 cells (SELIII). Marked differences were observed in the expression of the TcRα, CD3δ, LEF‐1 and PEBP2αA genes in BEL and SEL hybrids. Expression of the TcRα, CD3δ and LEF‐1 genes, which was extinguished in BELIII and BELIV, was detected in SELIII. PEBP2αA gene expression, not detected in S194 cells, was considerably reduced in SELIII. Almost the sum of the chromosomes from the parental cells were retained by, and the presence of every gene was proven, in each cell hybrid. These results suggest that suppression of the expression of lymphoid‐specific transcription factor genes may precede that of the TcR/CD3 genes in the cell hybrids, and that the presence of a different trans‐acting negative regulatory mechanism(s) suppresses the expression of T cell specific genes in fibroblasts and B cells.
Inhibition of resistance to hemopoietic allo‐grafts in granulocyte colony‐stimulating factor transgenic mice
Authors: Kokai Yasuo , Kaneko Hideo , Izuka Kooh , Matsuura Akihiro , Fujimoto Junichiro
Published: March 2007

Transplanted allogeneic marrow cells often fail to engraft in a lethally irradiated host. This phenomenon, termed resistance to allogeneic marrow grafts or allo‐resistance, is well documented, although its mechanism is not yet understood. Transplantation of major histocompatibility complex disparate allogeneic marrow cells into mice transgenic for granulocyte colony‐stimulating factor (G‐CSF) showed donor‐derived spleen colonies (CFU‐S) and resulted in stable allogeneic chimerism with excellent survival (100% up to 40 days and 89% up to 120 days). Under the same experimental conditions, all the littermate controls failed to show CFU‐S and died shortly after marrow transplantation. Thus, resistance to allogeneic marrow cells appeared to be severely impaired in this transgenic mouse. The observation that neutralizing antibody against G‐CSF restored allo‐resistance in G‐CSF transgenic mice and that CFU‐S was inducible upon administration of recombinant G‐CSF using a mini‐osmotic pump in non‐transgenic recipients, suggests that an elevated level of this cytokine is important for the inhibition of allo‐resistance. Thus, G‐CSF was found to play a role in allogeneic resistance to marrow grafts and the G‐CSF‐transgenic mice provide a useful model to study the inhibition of the resistance. The inhibition of allo‐resistance may be useful in preparing allogeneic bone marrow chimeras in both experimental and clinical settings.
Interleukin‐10 inhibits cytokine generation from mast cells
Authors: Arock Michel , Zuany‐Amorim Claudia , Singer Monique , Benhamou Marc , Pretolani Marina
Published: March 2007

This report examines the effect of recombinant murine interleukin‐10 (rmIL‐10) on antigen‐induced β‐hexosaminidase, leukotriene (LT)C4 and cytokine release from mouse bone marrow‐derived mast cells (BMMC). BMMC sensitized to hapten‐monoclonal IgE directed against dinitrophenol‐bovine serum albumin (DNP‐BSA) and challenged with 10 ng/ml DNP‐BSA generated β‐hexosaminidase and LTC4‐like material, which was followed by tumor necrosis factor‐α (TNF‐α) and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) mRNA expression and protein release. Incubation of BMMC with 1–100 ng/ml rmIL‐10 inhibited cytokine generation, without affecting β‐hexosaminidase and LTC4‐like material release. TNF‐α, but not GM‐CSF mRNA expression, was also diminished in rmIL‐10‐treated BMMC, suggesting that down‐regulation of cytokine production by rmIL‐10 involves different mechanisms. These results identify a novel biological action of IL‐10 as an inhibitor of cytokine production by stimulated mast cells.
Specific expression of surface interferon‐γ on interferon‐γ producing T cells from mouse and man
Authors: Assenmacher Mario , Scheffold Alexander , Schmitz Jürgen , Checa Juan Antonio Segura , Miltenyi Stefan , Radbruch Andreas
Published: March 2007

Interferon (IFN)‐γ is a potent immunoregulatory protein secreted by CD4+ and CD8+ T cells and by natural killer cells. Here, we show that IFN‐γ is specifically displayed at a low concentration on the cell surface of those activated T cells from mouse and man which express IFN‐γ. It is transiently expressed on the cell surface with kinetics similar to those of intracellular IFN‐γ expression. Detectable surface IFN‐γ is not expressed by activated T helper (Th) cells producing other cytokines but which do not express IFN‐γ. Thus, surface IFN‐γ is the first available marker for live T lymphocytes expressing IFN‐γ, e.g. Th1 cells.
Blimp‐1 overcomes the block in IgM secretion in lipopolysaccharide / anti‐μ F(ab′)2‐co‐stimulated B lymphocytes
Authors: Schliephake Dorothee E. , Schimpl Anneliese
Published: March 2007

A combination of signals transmitted through the antigen receptor, membrane‐bound cell interaction molecules and cytokine receptors induces B cell proliferation and differentiation into immunoglobulin‐secreting or memory cells. It has recently been suggested by Turner et al. (Cell 1994. 77: 297) that the complex changes in gene activities accompanying high levels of immunoglobulin secretion are under the common control of a master regulator, Blimp‐1 (B lymphocyte‐induced maturation protein). We show here that in naive mouse B cells stimulated with lipopolysaccharide (LPS) alone (which leads to high IgM production), Blimp‐1 is highly expressed, while cells co‐stimulated with LPS and anti‐μ F(ab′)2 show low levels of Blimp‐1 mRNA and no longer secrete Ig. Iγ1 sterile transcripts are, however, up‐regulated after receptor co‐ligation. Addition of interleukin (IL)‐2 and IL‐5 to LPS + anti‐μ F(ab′)2‐treated primary B cells led to up‐regulation of Blimp‐1 and IgM secretion. Transfection of a Blimp‐1 expression vector also induced IgM secretion. The data indicate that Blimp‐1 is an important regulator of immunoglobulin secretion by primary B cells, and suggest that its level of expression may determine the differentiation to Ig‐secreting plasma cells or entrance and maintenance in the memory pool.
Early development and progression of lymphocyte‐stimulatory cross‐reactive idiotypes expressed on antibodies to soluble egg antigens during Schistosoma mansoni infection of mice
Authors: Bosshardt Stephen C. , Nix Nancy A. , Colley Daniel G.
Published: March 2007

Idiotypes (Id) that stimulate immunoregulatory anti‐Id T lymphocyte proliferation are expressed on murine and human antibodies (Ab) to soluble egg antigens (SEA) of Schistosoma mansoni. Kinetics of early expression of these stimulatory Id have now been studied using immunoaffinity‐purified serum anti‐SEA Ab from mice infected with S. mansoni for 6, 7, 8, 12, or 16 weeks. Rabbit anti‐Id Ab specific for mouse anti‐SEA Id expressed at 8 weeks post‐infection (anti‐8WkId) demonstrated the strongest interactions with Id present at 7 and 8 weeks post‐infection by competitive enzyme‐linked immunosorbent assay. Anti‐8WkId Ab reacted progressively less well with 12WkId, 6WkId, and 16WkId. Splenocytes from mice infected for 8 weeks demonstrated the highest blast transformation responses in vitro to anti‐SEA Id from mice infected for 6 weeks, while 7, 8, 12, and 16 weeks post‐infection Id preparations stimulated progressively less proliferation. These data indicate that although eventual Id‐associated immunoregulatory events contribute to chronicity in this disease, production of anti‐SEA Ab that express stimulatory cross‐reactive immunoregulatory Id comprises a substantial portion of the initial, acute anti‐SEA response in mice infected with Schistosoma mansoni. Furthermore, either this particular Id‐expressing response is not maintained, or its proportional presence is greatly diminished by the cumulative production of other multiple anti‐SEA Ab during the establishment of chronicity, perhaps in response to its immunoregulatory influence very early in infection.
TAP1‐deficient mice select a CD8+ T cell repertoire that displays both diversity and peptide specificity
Authors: Sandberg Johan K. , Chambers Benedict J. , Van Kaer Luc , Kärre Klas , Ljunggren Hans‐Gustaf
Published: March 2007

Mice deficient in the gene encoding the transporter associated with antigen processing 1 (TAP1) are defective in providing major histocompatibility complex (MHC) class I molecules with cytosolic peptides. Consequently, these mice express reduced levels of MHC class I glycoproteins on the cell surface, and have reduced numbers of CD8+ T cells in the periphery. In the present study, we have addressed the diversity and specificity of the peripheral CD8+ T cell population in TAP1 ‐/‐ mice. CD8+ T cells were polyclonal with regard to T cell receptor (TCR) Vβ expression. Overall, Vβ usage in TAP1 ‐/‐ mice appeared to be very similar to that in wild‐type mice, with significantly reduced levels of Vβ5.1/5.2‐expressing CD8+ T cells as the only clear exception. This polyclonal population of CD8+ T cells readily mounted epitope‐specific CTL responses against four out of five well‐defined MHC class I‐restricted peptides. In contrast to allospecific CTL, peptide‐specific CTL from TAP1 ‐/‐ mice did not cross‐react on cells expressing normal levels of H‐2b class I. The present results demonstrate that a polyclonal CD8+ T cell repertoire, displaying both diversity and peptide specificity, is positively selected in mice devoid of a functional peptide transporter. These observations imply that TAP‐dependent peptides are not absolutely required for positive selection of a functionally diverse repertoire of CD8+ T cells.
CC chemokines induce the generation of killer cells from CD56+ cells
Authors: Maghazachi Azzam A. , Al‐Aoukaty Ala , Schall Thomas J.
Published: March 2007

We describe here that members of the CC chemokines exhibit biological activities other than chemotaxis. Macrophage inflammatory protein (MIP)‐1α, MIP‐1β, monocyte chemoattractant protein‐1 and RANTES, but not interleukin (IL)‐8, induce the generation of cytolytic cells, designated here as CHAK (CC chemokine‐activated killer) cells to distinguish them from IL‐2‐activated (LAK) cells. Like IL‐2, CC chemokines can induce the proliferation and activation of killer cells. While incubating CC chemokines with CD4+ or CD8+ cells did not generate CHAK activity, all CC chemokines were capable of inducing CHAK activity upon incubating with CD56+ cells, suggesting that the primary effectors are NK cells. However, the presence of other cell types, such as CD4+ or CD8+, are necessary to induce the proliferation of CD56+ cells. Confirming the involvement of T cell‐derived factors in inducing the proliferation of these cells, anti‐IL‐2 and anti‐interferon‐γ, but not anti‐IL‐1β, anti‐tumor necrosis factor‐α, anti‐IL‐8, or anti‐granulocyte/monocyte‐colony‐stimulating factor inhibited RANTES‐induced proliferation of nylon wool column‐nonadherent cells. Our results may have important clinical applications for the utilization of CHAK cells in the treatment of cancer and immunodeficient patients.
CD8/CD4 lineage commitment occurs by an instructional/default process followed by positive selection
Authors: Benveniste Patricia , Knowles Gisele , Cohen Amos
Published: March 2007

In the present study, we investigated the developmental potential of purified populations of transitional CD4in CD8hi and CD4hi CD8in thymocytes that were further defined according to their differentiation stage by their levels of T cell receptor (TCR) expression into TCRlo, TCRin and TCRhi subpopulations. The differentiation potential of each of these subsets was tested in vitro in a single‐cell suspension culture assay that showed that CD4in CD8hi TCRhi are precursors of CD8 single‐positive cells, whereas CD4hi CD8in TCRin/hi are precursors of both CD4 and CD8 single‐positive thymocytes. The analysis of transitional subsets in mutant mice for either β2‐microglobulin or major histocompatibility complex (MHC) class II further revealed that lineage commitment to the CD8 lineage requires a TCR‐MHC class I engagement, presumably at the immature double‐positive stage of thymic development, while CD4 commitment does not require an MHC class II‐mediated signal, but rather occurs by default. Using the addition of MHC class I‐ or class II‐expressing cells or the addition of total thymocytes to purified sorted transitional precursors for the duration of the cultures in vitro, we identified an additional stage of differentiation for both CD4 and CD8 lineages that requires a positive selection signal. Examination of protein tyrosine phosphorylation of transitional precursors revealed that CD4in CD8hi transitional cells contain a high level of a 70‐kDa phosphorylated protein consistent with a role for ZAP70 in the signal transduction during the positive selection of CD8+ cells.
Inhibition of thymocyte negative selection by T cell receptor antagonist peptides
Authors: Williams Owen , Tanaka Yujiro , Bix Mark , Murdjeva Marianna , Littman Dan R. , Kioussis Dimitris
Published: March 2007

The T cell receptor (TCR) recognizes antigenic peptide presented by major histocompatibility complex (MHC) molecules. Analogs of antigenic peptides have been shown to inhibit antigen‐specific T cell responses, a phenomenon described as TCR antagonism. We have examined the effect of a natural variant of an antigenic peptide and a synthetic peptide analog, on the responses of mature T cells and immature thymocytes from an αβ TCR‐transgenic mouse (F5), the TCR of which recognizes a nonamer peptide from the nucleoprotein (NP) of influenza virus in the context of the H‐2Db MHC molecule. Both peptides were shown to antagonize specifically the T cell cytolytic response without being able directly to stimulate mature T cells from these transgenic mice. Furthermore, a negative selection assay in vitro was used to demonstrate for the first time that antagonistic peptides are capable of antagonizing thymocyte deletion induced by antigenic peptides. These data suggest that the final selection of a T cell could be the result of a balance between the positive and negative influences of endogenous peptide ligands.
Interleukin‐13 is produced by activated human CD45RA+ and CD45R0+ T cells: modulation by interleukin‐4 and interleukin‐12
Authors: Jung Thomas , Wijdenes John , Neumann Christine , de Vries Jan E. , Yssel Hans
Published: March 2007

Interleukin (IL)‐13 is a cytokine originally identified as a product of activated T cells. Little is known, however, about IL‐13 production by human T cells and its modulation by other cytokines. Here, we show that IL‐13 is produced by activated human CD4+ and CD8+ CD45R0+ memory T cells and CD4+ and CD8+ CD45RA+ naive T cells. In contrast, IL‐4, which shares many biological activities with IL‐13, is only produced by CD45R0+ T cells following activation. Analysis of intracellular cytokine production by single CD45RA+ and CD45R0+ T cells indicated that IL‐13 continued to be produced for more than 24 h after stimulation, whereas IL‐4 could not be detected after 24 h. These data were confirmed by measurement of specific mRNA and suggest that IL‐13, unlike IL‐4, but like interferon‐γ (IFN‐γ), is a cytokine with long‐lasting kinetics. The majority of human CD45R0+ T cells produced IL‐4 and IL‐13 simultaneously. In contrast, IFN‐γ protein was generally not co‐expressed with IL‐4 or IL‐13. IL‐4 added to primary cultures of highly purified peripheral blood T cells activated by the combination of anti‐CD3+anti‐CD28 mAb enhanced IL‐13 production by CD45RA+ and to a lesser extent by CD45R0+ T cells. Under these conditions, however, IL‐12 inhibited IL‐13 production by CD45RA+ T cells and to a lesser extent by CD45R0+ T cells in a dose‐dependent fashion. These inhibiting effects were not related to enhanced IFN‐γ production induced by IL‐12, since IFN‐γ by itself did not affect IL‐13 production. Collectively, our data indicate that IL‐13 is produced by peripheral blood T cells which also produce IL‐4, but not IFN‐γ, and by naive CD45RA+ T cells which, in contrast, fail to produce IL‐4. These observations, together with the long‐lasting production of IL‐13, suggest that IL‐13 may have IL‐4‐like functions in situations where T cell‐derived IL‐4 is still absent or where its production has already been down‐regulated.
The Jβ segment of the T cell receptor contributes to the Vβ‐specific T cell expansion caused by staphylococcal enterotoxin B and Urtica dioica superantigens
Authors: Musette Philippe , Galelli Anne , Truffa‐Bachi Paolo , Peumans Willy , Kourilsky Philippe , Gachelin Gabriel
Published: March 2007

We have used a new polymerase chain reaction‐based technique to analyze at the clonal level the CDR3 diversity and the Jβ usage associated with the Vβ‐dependent T cell receptor (TCR) recognition of two superantigens: the staphylococcal enterotoxin B and the Urtica dioica agglutinin. Our results show that a subset of Jβ elements is preferentially expanded in a given Vβ family, independently of the nature of the superantigen. By contrast, the CDR3 loop does not contribute significantly to the T cell expansion induced by the superantigens. We conclude that the Jβ segment of the TCR β chain, but not the CDR3 region, participates in superantigen binding, presumably by influencing the quaternary structure of the TCR β chain.
Rapid killing of murine lymph node T blasts by intestinal intraepithelial lymphocytes in vitro
Authors: Kawamoto Yasuko , Sasaki Keiko , Kato Yutaka , Kojima Keisuke , Tsuji Takao , Miyama Akio
Published: March 2007

We examined the effect of murine intestinal intraepithelial lymphocytes (IEL) on the proliferation of murine lymph node T cells (LN‐T) in vitro. An IEL fraction prevented the proliferation of LN‐T stimulated with antigen and X‐irradiated spleen cells, or with anti‐CD3 monoclonal antibodies (mAb). Concanavalin A‐activated LN‐T were less sensitive. Such an inhibitory activity was recovered from a CD8‐depleted population by panning of bulk IEL using anti‐CD8α mAb. This population of BALB/c IEL showed less granzyme A activity, and its surface markers were positive for CD8 (∼4%), CD3 (80–90%), CD4 (2–6%), αβTcR (45–70%), and γδTcR (4–9%). Asialo‐GM1 and Thy1.2 were variably expressed, but interleukin‐2 (IL‐2) receptor‐α and FcγR were not. By contrast, no cytotoxicity against YAC‐1 was detected in a CD8‐depleted IEL population by a 6‐h 51Cr‐release assay. Although IEL from severe‐combined immunodeficient mice lacking CD4, CD8 and TcR, but expressing IL‐2 receptor, showed cytotoxicity against YAC‐1, their inhibitory activity against LN‐T was almost the same as that by IEL from BALB/c mice. When LN‐T blasts (>75% CD4+) activated with anti‐CD3 were treated with CD8‐depleted IEL, intact cellular DNA of the T blasts disappeared within 1 h with increased amounts of small‐sized DNA. These results suggest that CD8− IEL directly and nonspecifically kill lymph node CD4+ T blasts and possibly down‐regulate TcR‐mediated proliferation of peripheral T cells in the gut epithelium.
A third interferon‐γ‐induced subunit exchange in the 20S proteasome
Authors: Groettrup Marcus , Kraft Regine , Kostka Susanne , Standera Sybille , Stohwasser Ralf , Kloetzel Peter‐M.
Published: March 2007

The 20S proteasome is a protease complex of functional importance for antigen processing. Two of the 14 proteasome subunits, δ and MB1, can be replaced by the major histocompatibility complex (MHC)‐encoded and interferon‐γ (IFN–γ)‐inducible subunits LMP2 and LMP7, respectively. LMP2 and LMP7 alter the cleavage site specificity of the 20S proteasome and are required for the efficient generation of T cell epitopes from a number of viral proteins and for optimal MHC class I cell surface expression. We compared the 20S proteasome subunit pattern from IFN‐γ‐induced and non‐induced mouse fibroblasts on two‐dimensional gels and identified a third subunit exchange by microsequencing: the non‐MHC‐encoded subunit MECL‐1 is induced by IFN‐γ and replaces a so‐far barely characterized β subunit designated ‘MC14’. In analogy to LMP2 and LMP7, MECL‐1 may be functional in MHC class I‐restricted antigen presentation.
A novel “chimeric” antibody class in cartilaginous fish: IgM may not be the primordial immunoglobulin
Authors: Greenberg Andrew S. , Hughes Austin L. , Guo Jian , Avila David , McKinney E. Churchill , Flajnik Martin F.
Published: March 2007

Using a degenerate oligonucleotide primer specific for immunoglobulin (Ig) constant type 1 (C‐1 set) domain genes, products were amplified by the reverse transcriptase‐polymerase chain reaction from nurse shark spleen cDNA. The deduced protein sequence of one of these clones reveals a novel Ig class in cartilaginous fish. A complete mRNA could encode a mature protein bearing an amino‐terminal variable (V) domain, followed by six C‐1 set domains, and ending in a carboxy‐terminal tail typical of secreted IgM, IgA, and the new antigen receptor (NAR). The two amino‐terminal C domains are orthologous to IgX (or IgR), an Ig heavy (H) chain class in the skate, and the last four domains are homologous to the carboxy‐terminal four domains of NAR. We designate this “chimeric” Ig class IgNARC for Ig new antigen receptor from cartilaginous fish. Like NAR, but unlike shark IgM, IgNARC is encoded by very few V and C genes which apparently are not closely linked. The number of bands that hybridize with exon‐specific probes varies with genomic DNA from individual sharks, suggestive of different numbers of IgNARC genes in different animals. A protein of approximately 95 kDa, which is likely to be the IgNARC H chain, is immunoprecipitated with both light chain‐specific monoclonal antibodies and with antisera generated to a peptide comprising the IgNARC carboxy‐terminal tail. We conclude that the arsenal of secreted antigen receptors in cartilaginous fish is greater than previously believed. In addition, our data cast doubt on the dogma that IgM is the primordial Ig isotype.
Polyclonal expansion of adoptively transferred CD4+ αβ T cells in the colonic lamina propria of scid mice with colitis
Authors: Rudolphi Angelika , Bonhagen Kerstin , Reimann Jörg
Published: March 2007

The adoptive transfer of low numbers of peripheral, non‐fractionated CD4+ αβ T cells into histocompatible, severely immunodeficient (scid) hosts induces a colitis. This disease developed in C.B‐17 scid/scid hosts after the injection of 105CD4+ T cells purified from different peripheral lymphoid organs of immunocompetent C.B‐17 +/+ or BALB/cdm2 donor mice. Irrespective of their tissue origin, transferred CD4+ T cells selectively repopulated the scid host with gut‐seeking CD4+ T cells. A chronic inflammatory bowel disease (IBD) developed as polyclonal populations of mucosa‐seeking memory/effector CD4+ T cells accumulated in the gut lamina propria and epithelial layer of the adoptive host. The manifestation of colitis in the scid host correlated with the in situ polyclonal activation and expansion of adoptively transferred CD4+ T cells in the colonic lamina propria. Attempts were unsuccessful to select in vivo an oligoclonal CD4+ T cell population with an enhanced IBD‐inducing potential by repeatedly reinjecting 105 donor‐type CD4+ T cells from the colonic lamina propria of transplanted scid mice with an early and severe IBD into new scid hosts. The data indicate that the preferential repopulation of gut‐associated lymphoid tissues with immunocompetent CD4+ T cells, and their polyclonal activation and in situ expansion in the lamina propria of the histocompatible, immunodeficient host are critical events in the pathogenesis of an IBD in this model.
The role of oxygen in thymocyte apoptosis
Authors: McLaughlin Kelly A. , Osborne Barbara A. , Goldsby Richard A.
Published: March 2007

Signals generated by T cell receptor (TCR) cross‐linking (or phorbol 12‐myristate‐13‐acetate + Ca2+ ionophore), glucocorticoids or ionizing radiation all stimulate apoptotic cell death in thymocytes by signals that are initially distinct from each other. However, when these stimuli were administered to thymocyte cultures that were maintained under an atmosphere containing less than 20 ppm oxygen as opposed to one that contained 18.5 % molecular oxygen, cell death was inhibited or abrogated, suggesting that the induction of death by all three different stimuli depend on the presence of molecular oxygen. Studies of the effects of the cysteine analog N‐acetyl cysteine (NAC) with normal thymocytes demonstrated that this antioxidant inhibited the induction of death by each of the different stimuli in a manner that paralleled anaerobiosis. Furthermore, studies with thymocytes demonstrated that the induction of nur77, a gene shown to be involved in thymocyte apoptosis signaled through the TCR or its surrogates, is not inhibited by NAC or dependent upon molecular oxygen. The possible implications for negative selection of NAC‐mediated inhibition of TCR‐signaled thymocyte cell death was examined in thymic organ culture. Treatment of these cultures with NAC provided significant protection against staphylococcal enterotoxin B‐mediated deletion of Vβ8‐expressing thymocytes.
Differential modulation of B7‐1 and B7‐2 isoform expression on human monocytes by cytokines which influence the development of T helper cell phenotype
Authors: Creery W. David , Diaz‐Mitoma Francisco , Filion Lionel , Kumar Ashok
Published: March 2007

The co‐stimulatory molecules B7‐1/B7‐2 expressed on the surface of antigen‐presenting cells have been suggested to influence the development of T helper 1 (Th1)‐versus Th2‐immune responses. These studies were conducted to elucidate the effect of immunoregulatory cytokines which influence the development of Th1/Th2 immune responses on the expression of the B7 isoforms B7‐1 and B7‐2 on resting and activated human monocytes and B cells. Interleukin (IL)‐4 and IL‐10, which induce the development of Th2 immune responses, down‐regulated B7‐2 and moderately up‐regulated B7‐1 expression on resting CD14+ monocytes in peripheral blood mononuclear cells. Interferon‐γ (IFN‐γ), which induces the development of Th1 immune responses, enhanced the expression of both B7‐1 and B7‐2 isoforms. Tumor necrosis factor (TNF)‐α, which elicits both Th1‐ and Th2 characteristics depending on experimental conditions, down‐regulated B7‐2 but did not alter B7‐1 expression. The effect of TNF‐ä and B7‐2 expression is not mediated through endogenously produced IL‐10, as addition of anti‐IL10 antibodies did not restore B7‐2 expression. None of the other cytokines tested, including IL‐1α, IL‐1β, IL‐2, IL‐5, IL‐6, IL‐12, granulocyte/macrophage colony‐stimulating factor (GM‐CSF), and transforming growth factor (TGF)‐α, modulated the expression of B7 isoforms on resting monocytes. Lipoolysaccharide stimulation of monocytes down‐regulated B7‐2 and up‐regulated B7‐1 expression in a manner similar to IL‐10. The expression of B7‐1 and B7‐2 on purified B cells were not altered by any of the cytokines tested, including IL‐1α, IL‐1β, IL‐2, IL‐4, IL‐5, IL‐6, IL‐10, IL‐12, IFN‐γ, TNF‐α, TGF‐α and GM‐CSF. Taken together, our results suggest that the cytokines which induce Th1/Th2 immune responses exert differential effects on B7 isoform expression on resting monocytes but have no effect on resting or activated B cells.
HLA‐associated inverse correlation between T cell and antibody responsiveness to islet autoantigen in recent‐onset insulin‐dependent diabetes mellitus
Authors: Roep Bart O. , Duinkerken Gaby , Schreuder Geziena M. T. , Kolb Hubert , de Vries René R. P. , Martin Stephan
Published: March 2007

Insulin‐dependent diabetes mellitus (IDDM) is a T cell‐dependent immune‐mediated disease. Recently, a novel islet cell antigen (ICA69) recognized by autoantibodies was described. We tested T cell responsiveness to ICA69 in peripheral blood of patients with recent onset IDDM (n = 46), patients with long‐standing IDDM (n = 44), non‐diabetic age‐matched, islet cell autoantibody‐ and glutamic acid decarboxylase (GAD)65 antibody‐negative first‐degree relatives of IDDM patients (n = 15) and rheumatoid arthritis patients (n = 22). T cell responsiveness was significantly higher in recent onset IDDM patients, compared to IDDM patients post‐disease onset, non‐diabetic first degree relatives and rheumatoid arthritis patients (p < 0.001). In responding IDDM patients a significant inverse correlation between T cell and autoantibody responsiveness to ICA69 was observed (p < 0.0005). Immunogenetic evaluation revealed an association of HLA‐DR3 with T cell responsiveness to ICA69 (p < 0.02) and absence of ICA69‐reactive autoantibodies (p < 0.04). The increased T cell reactivity to ICA69 in the absence of antibody reactivity at onset of IDMM is associated with an HLA class II immune response gene, and therefore suggestive of a genetically controlled selective activation of T helper subsets to a specific autoantigen in humans.
Dispensability of Jak1 tyrosine kinase for interleukin‐2‐induced cell growth signaling in a human T cell line
Authors: Higuchi Masaya , Asao Hironobu , Tanaka Nobuyuki , Oda Katsuhiko , Takeshita Toshikazu , Nakamura Masataka , Van Snick Jacques , Sugamura Kazuo
Published: March 2007

The tyrosine kinases Jak1 and Jak3 are known to be associated with the β and γ chains of interleukin‐2 receptor (IL‐2R). They are activated by stimulation with IL‐2, IL‐4, IL‐7, IL‐9, or IL‐15, receptors of which share the γ chain of the IL‐2R. We have obtained direct evidence of Jak1 association with the α chains of receptors for IL‐4, IL‐7 and IL‐9 and with the β chain of IL‐2R, which is also common to the IL‐15R. Furthermore, we have prepared mutant IL‐2R β chains with a mutation in the box 1 region, which is conserved among the IL‐2R β chain and the α chains of the other cytokine receptors sharing the IL‐2R γ chain. Using MOLT‐4 transfectants with the mutant β chains, we found that two conserved proline residues within the box 1 region are essentially involved in association with Jak1. The MOLT‐4 transfectants with the mutant β chains lacking Jak1 association showed IL‐2 responsiveness, in terms of activation of Jak3 and Stat5 and induction of cell growth, indicating that Jak1 is dispensable for IL‐2‐mediated cell growth signaling and that Jak1 activation is not required for activation of Jak3 and Stat5 in the MOLT‐4 transfectants.
On the interaction between agalactosyl IgG and Fcγ receptors
Authors: Groenink Jasper , Spijker Jeroen , van den Herik‐Oudijk Ingrid E. , Boeije Leonie , Rook Graham , Aarden Lucien , Smeenk Ruud , van de Winkel Jan G. J. , van den Broek Maries F.
Published: March 2007

One of the serum abnormalities observed in autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) is the occurrence of IgG that lacks the terminal galactose on asparagine‐linked biantennary complex type oligosaccharides [Gal(0)‐IgG] located in the CH2 domain. Additionally, IgG without glycosylation is known to be defective in several effector functions due to a reduced ability to bind to its specific receptors (FcγR). It has thus been speculated that, by analogy with unglycosylated IgG, Gal(0)‐IgG may also be functionally impaired or exert altered effector mechanisms. If this were true, Gal(0)‐IgG could contribute to the phenotype of above‐mentioned autoimmune diseases, like impaired immune complex clearance and defective down‐regulation of activated B cells. Here, we show by three different methods that the interaction of Gal(0)‐IgG and normally glycosylated IgG with the low‐affinity FcγRII (CD32) is indistinguishable with respect both to binding and receptor‐mediated signalling. These data argue against a prominent role for FcγR‐dependent Gal(0)‐IgG interactions in the etiology or pathogenesis of autoimmune diseases.
Semi‐allogeneic (F1) versus fully allogeneic blood transfusions: differences in their ability to induce specific immunological unresponsiveness
Authors: Roelen Dave L. , Dover Emma L. , Niimi Masanori , Young Neil T. , Morris Peter J. , Wood Kathryn J.
Published: March 2007

The beneficial effect on graft survival achieved by pretransplant blood transfusions is well established. However, the type of major histocompatibility complex (MHC) mismatch between transfusion donor and recipient seems to play a role in determining the outcome. The hypothesis that this sharing of MHC antigens is correlated with the level of sensitization or tolerization was studied in mice by pretreatment with semi‐allogeneic (F1) or with fully allogeneic whole blood transfusions. Limiting dilution analysis (LDA) in vitro for donor‐specific T helper (Thp) and cytotoxic T lymphocyte precursors (CTLp) performed on splenocytes isolated from transfused recipients 2 or 4 weeks after transfusion showed that the duration and magnitude of the response was reduced after a semi‐allogeneic compared to a fully allogeneic transfusion. After a semi‐allogeneic transfusion, both Thp and CTLp frequencies had returned to naive levels 4 weeks after transfusion, whereas after infusion of fully allogeneic blood, they remained elevated after 4 weeks. When a fully allogeneic heart was transplanted 2 or 4 weeks after transfusion, a small but significant improvement in graft prolongation (2 weeks, not significant, 4 weeks: p < 0.01) was observed following pretreatment with a semi‐allogeneic transfusion (2 weeks: median survival time (MST) 30 days, 4 weeks: MST 29 days) compared to that obtained after fully allogeneic transfusion (2 weeks: MST 23 days, 4 weeks: MST 12 days). The semi‐allogeneic transfusions were correlated with a statistically significant prolonged (7 days) persistence of donor‐derived MHC class II+ cells in the recipient and with reduced levels of anti‐donor MHC class I‐specific antibody formation compared to these responses after transfusion with fully allogeneic cells. These results demonstrate that pretreatment with a semi‐allogeneic blood transfusion is more tolerizing and less sensitizing than pretreatment with a fully allogeneic blood transfusion. These findings may be explained by the sharing of MHC antigens between recipient and transfusion donor.
Neonatal and early life immune responses to various forms of vaccine antigens qualitatively differ from adult responses: predominance of a Th2‐biased pattern which persists after adult boosting
Authors: Barrios Christy , Brawand Pierre , Berney Monika , Brandt Christian , Lambert Paul‐Henri , Siegrist Claire‐Anne
Published: March 2007

Induction of neonatal immune responses to vaccine antigens is believed to be of limited efficacy because of immune immaturity and particular susceptibility to tolerogenic signals during this period of life. To characterize particular features of neonatal immune responses to vaccine antigens, we assessed the capacity of BALB/c mice at different stages of immunological maturation to respond to a selection of vaccine antigens and presentation systems. Significant B and T cell responses to vaccine antigens (tetanus and measles virus peptides, tetanus toxoid, live viral attenuated measles virus, canarypox recombinant measles vector or bacillus Calmette‐Guérin) were obtained as early as the first week of life. However, these neonatal responses differed qualitatively from adult responses by a decreased IgG2a/IgG1 ratio of vaccine‐specific antibodies, the secretion of significantly higher interleukin‐5 and lower interferon‐γ levels by vaccine‐specific T cells and an impaired induction of cytotoxic T cell precursors. This pattern of biased Th2 versus Th1 responses induced upon early exposure to vaccines was not reversed by decreasing the doses of vaccine antigens. It did not disappear with aging and was still reflected in adult responses to booster immunization with the corresponding antigen. Thus, neonatal immunization can induce significant vaccine specific responses with a predominance of a Th2 pattern which can persist in boosted adult mice.
Human lymphocytes shed a soluble form of CD21 (the C3dg/Epstein‐Barr virus receptor, CR2) that binds iC3b and CD23
Authors: Frémeaux‐Bacchi Véronique , Bernard Isabelle , Maillet Françoise , Mani Jean‐Claude , Fontaine Marc , Bonnefoy Jean‐Yves , Kazatchkine Michel D. , Fischer Elizabeth
Published: March 2007

We report on a soluble (s) form of CD21 (the C3dg/Epstein‐Barr virus receptor, CR2) that is spontaneously released by B and T lymphocytes. Immunoprecipitation with anti‐CD21 mAb of culture supernatants of surface and biosynthetically labeled B and T cell lines revealed a single band with an apparent molecular mass of 135 kDa. The molecule exhibited a molecular mass 10 kDa lower than that of membrane CD21. The release of soluble CD21 (sCD21) was time dependent and correlated with a parallel decrease in the expression of the membrane‐associated molecule. The protein was also found in culture supernatants of tonsillar B cells and normal human thymocytes. Epitopic analysis using combinations of anti‐CD21 monoclonal antibodies (mAb) indicated that sCD21 and membrane CD21 were similarly recognized by mAb directed against short concensus repeats (SCR) 1–2, SCR 4–5 and SCR 9–11. Affinity‐purified sCD21 was capable of binding to purified human iC3b and to human recombinant CD23, as assessed by enzyme‐linked immunosorbent assay and by using the BIAcoreTM technology. In addition, normal human serum was found to contain a soluble form of CD21 that exhibited a similar molecular mass to that of the molecule shed by B and T cells in culture. The serum form of CD21 was recognized by all anti‐CD21 mAb that we tested and showed a high reactivity with mAb directed against SCR 1–2. Our observations suggest that B and T cells shed the extracellular portion of CD21 and release a soluble molecule that retains the ligand‐binding properties of CD21, thus having a potential role in immunoregulation.
An IgG‐transporting Fc receptor expressed in the syncytiotrophoblast of human placenta
Authors: Simister Neil E. , Story Craig M. , Chen Hua‐Liu , Hunt Joan S.
Published: March 2007

During normal human pregnancy, maternal IgG crosses the placenta and provides passive immunity for the fetus. In so doing, IgG passes through two cellular barriers: the syncytiotrophoblast and the fetal capillary endothelium. The Fc region of IgG is required for its transport across the placenta, but the Fc receptors responsible have not been identified definitively. We recently reported the isolation from a placental cDNA library of clones encoding the α chain of a human homologue of the major histocompatibility complex class I‐related Fc receptor, the neonatal Fc receptor (FcRn). In mice, FcRn is essential for the transport of maternal IgG to the fetus and the neonate. We report here the localization of human FcRn mRNA within the placenta by in situ hybridization, and of human FcRn protein by immunohistochemistry. Both methods show that human FcRn is expressed in syncytiotrophoblast, and is, thus, appropriately located to transport maternal IgG across the first barrier. We confirm previous findings that specific binding of IgG to placental membranes is greater at pH 6.0 than pH 7.5. This corresponds with the pH dependence of IgG binding to FcRn and is consistent with the presence of FcRn in syncytiotrophoblast. We propose a transport model in which maternal IgG binds FcRn at low pH in endosomes within the syncytiotrophoblast. FcRn is not expressed in fetal capillary endothelia, and the mechanism of IgG transport across the second barrier remains unknown.
CD28/CTLA4‐B7 interaction is dispensable for T cell stimulation by mouse mammary tumor virus superantigen but not for B cell differentiation and virus dissemination
Authors: Champagne Eric , Scarpellino Leonardo , Lane Peter , Acha‐Orbea Hans
Published: March 2007

B cells are the primary targets of infection for mouse mammary tumor virus (MMTV). However, for productive retroviral infection, T cell stimulation through the virally‐encoded superantigen (SAG) is necessary. It activates B cells and leads to cell division and differentiation. To characterize the role of B cell differentiation for the MMTV life cycle, we studied the course of infection in transgenic mice deficient for CD28/CTLA4‐B7 interactions (mCTLA4‐Hγ1 transgenic mice). B cell infection occurred in CTLA4‐Hγ1 transgenic mice as integrated proviral DNA could be detected in draining lymph node cells early after infection by polymerase chain reaction analysis. In mice expressing I‐E, B cells were able to present the viral SAG efficiently to Vβ6+ T cells. These cells expanded specifically and were triggered to express the activation marker CD69. Further stages of progression of infection appeared to be defective. Kinetics experiments indicated that T and B cell stimulation stopped more rapidly than in control mice. B cells acquired an activated CD69+ phenotype, were induced to produce IgM but only partially switched to IgG secretion. Finally, the dissemination of infected cells to other lymph nodes and spleen was reduced and the peripheral deletion of Vβ6+ T cells was minimal. In contrast, in mice lacking I‐E, T cell stimulation was also impaired and B cell activation undetectable. These data implicate B7‐dependent cellular interactions for superantigenic T cell stimulation by low‐affinity TCR ligands and suggest a role of B cell differentiation in viral dissemination and peripheral T cell deletion.
The mouse immunoglobulin ϰ locus contains about 140 variable gene segments
Authors: Kirschbaum Thomas , Jaenichen Rita , Zachau Hans G.
Published: March 2007

In continuation of our efforts to elucidate the immunoglobulin ϰ locus of the mouse we analyzed 46 yeast artificial chromosomes (YACs) containing Vϰ, Jϰ and Cϰ genes. The YACs, which were derived from DNA of C57BL/6 and C3H mice, ranged from 0.3–1.9 Mb in size. On the basis of hybridization with probes specific for the Vϰ gene families a group of 13 YACs was selected for detailed analysis. The Vϰ genes of the YACs were then characterized by hybridization to the family‐specific probes and by the sizes of the EcoRI fragments on which they were found. This way evidence was obtained for 140 different Vϰ gene signals on the YACs. Of these 63 had been characterized before on clones from a cosmid library of total mouse DNA (I. Zocher et al., Eur. J. Immunol. 1995. 25: 3326–3331) and 22 others were found now on cosmid clones derived from the YACs. Six Vϰ genes of the previous study which were not found on the YACs are probably located outside of the ϰ locus. The YACs were arrayed in a unique order establishing a YACs panel which most likely contains the whole ϰ locus. The cosmid contigs and solitary cosmid clones which contain the 63 plus 22 Vϰ gene signals mentioned above comprise about 2.0 Mb. Assuming that the remaining 55 Vϰ genes are spaced at the same average distance of 24 kb, one may extrapolate to a locus size of 3.3 Mb.
Peptide‐pulsed dendritic cells induce tumoricidal cytotoxic T lymphocytes from healthy donors against stably HLA‐A*0201‐binding peptides from the Melan‐A/MART‐1 self antigen
Authors: van Elsas Andrea , van der Burg Sjoerd H. , van der Minne Carolien E. , Borghi Martina , Mourer Jacqueline S. , Melief Cornelis J. M. , Schrier Peter I.
Published: March 2007

The melanoma antigen Melan‐A/MART‐1 was screened for the presence of potential HLA‐A*0201‐binding cytotoxic T lymphocytes (CTL) epitopes. The immunodominant nonamer epitope AAGIGILTV demonstrated weak binding to T2 but a significant half‐life of binding to HLA‐A*0201 in contrast to the decamer EAAGIGILTV. In addition to the immunodominant CTL epitope, we describe two peptides, GILTVILGV and ALMDKSLHV, that display stable binding to HLA‐A*0201. Using cultured autologous dendritic cells pulsed with these peptides, CTL lines were induced from peripheral blood lymphocytes that displayed reactivity with HLA‐A2+, Melan‐A/MART‐1+ melanoma cells. CTL reactivity against the immunodominant epitope could be induced with the nonamer epitope alone, but not with the decamer variant. CTL clones generated from an (EAAGIGILTV + AAGIGILTV)‐induced CTL line recognize the appropriate melanoma cells and normal melanocytes. Upon further characterization of one of these CTL clones, it was found to be of surprisingly high affinity considering that it is directed against a self antigen. This study demonstrates that immunogenic peptides can be selected based on stability (half‐life) of peptide/HLA binding. In addition, cultured DC were found to efficiently induce CTL responses in vitro against such selected peptides, and some of these CTL were capable of recognizing endogenously processed antigen.
Urtica dioica agglutinin, a Vβ8.3‐specific superantigen, prevents the development of the systemic lupus erythematosus‐like pathology of MRL lpr/lpr mice
Authors: Musette Philippe , Galelli Anne , Chabre Henri , Callard Patrice , Peumans Willy , Truffa‐Bachi Paolo , Kourilsky Philippe , Gachelin Gabriel
Published: March 2007

The Vβ8.3‐specific superantigenic lectin Urtica dioica agglutinin (UDA) was used to delete the Vβ8.3+ T cells in MRL lpr/lpr mice. In contrast to the systemic lupus erythematosus‐like pathology which progresses with age in the phosphate‐buffered saline‐injected MRL lpr/lpr controls, UDA‐treated animals did not develop overt clinical signs of lupus and nephritis. The pathogenic T cell clones thus reside within the Vβ8.3+ T cell population, which includes an expanded T cell clone described previously. Finally, UDA alters the production of autoantibodies in a sex‐dependent manner.
Lack of oral tolerance but oral priming for contact sensitivity to dinitrofluorobenzene in major histocompatibility complex class II‐deficient mice and in CD4+ T cell‐depleted mice
Authors: Desvignes Cyril , Bour Héléne , Nicolas Jean‐François , Kaiserlian Dominique
Published: March 2007

Oral tolerance is defined by immune unresponsiveness after oral administration of soluble antigens and by antigen‐specific inhibition of peripheral immune responses induced by prior antigen feeding. The aim of this study was to investigate the implication of the major histocompatibility complex (MHC) class II presentation pathway to CD4+ T cells in oral tolerance of contact sensitivity (CS) to the hapten dinitrofluorobenzene (DNFB). We used MHC class II knockout (ABº/º) and invariant chain knockout (Iiº/º) mice, which have, respectively, a total or partial defect in class II‐restricted activation of CD4+ T cells, as well as normal C57BL/6 mice depleted of CD4+ T cells by injection of a specific antibody. Intragastric administration of DNFB prior to skin sensitization induced specific inhibition of contact sensitivity to DNFB in Aβ+/º and Ii+/º heterozygotes comparable to that observed in C57BL/6 mice. In contrast, no oral tolerance was observed in either MHC class II‐deficient Aβº/º and Iiº/º homozygote mutants or in syngeneic anti‐CD4‐depleted C57BL/6 mice. Moreover, a single oral administration of DNFB, without skin sensitization, could prime Aβº/º, Iiº/º as well as anti‐CD4‐depleted C57BL/6 mice for DNFB‐specific CS. These findings demonstrate that the class II/CD4 pathway is involved in oral tolerance manifested both as the inhibition of CS by hapten feeding prior to skin sensitization, and as immune unresponsiveness of normal mice to oral administration of hapten. Furthermore, our data provide evidence that a single oral feeding with DNFB is able to prime mice for hapten‐specific CS, provided that the class II/CD4 pathway is bypassed.