bluuebunny/crossref_metadata_2025_split huggingface dataset:
RAG1 and RAG2 expression in human intestinal epithelium: evidence of extrathymic T cell differentiation
Authors: Lynch Sara , Kelleher Dermot , McManus Ross , O'Farrelly Cliona 
Published: March 2007

AbstractWe examined the hypothesis that the adult human gastrointestinal tract is a site of extrathymic T cell differentiation. When T lymphocytes undergo gene rearrangement, the products of both RAG1 and RAG2 genes are expressed; RAG mRNA is present only in tissue governing lymphocyte maturation. In this study, reverse transcription polymerase chain reaction (RT‐PCR) was used to detect RAG1‐ and RAG2‐specific mRNA. Total RNA was purified from small intestinal samples from five adults. Peripheral blood mRNA from the same patient was used as a negative control in two cases. Bone marrow RNA preparations from two healthy donors were used as positive controls. cDNA synthesis was carried out using random hexamers. Primers for first round and nested PCR of RAG1 and RAG2 were synthesized. RAG1 and RAG2 mRNA was detected in all bone marrow preparations but was absent in all peripheral blood samples. RAG1 and RAG2 mRNA was detected in the small intestine of four of the five patients studied. RAG1 and RAG2 expression was localized in the epithelial layer and absent in the lamina propria. RAG1 and RAG2 expression in the epithelial layer is strong evidence that T cell differentiation occurs in the adult human intestine.
Evidence for the stochastic acquisition of cytokine profile by CD4+ T cells activated in a T helper type 2‐like response in vivo
Authors: Kelso Anne , Groves Penny , Troutt Anthony B. , Francis Kari 
Published: March 2007

AbstractThe diversity of cytokine production patterns displayed by T cells activated in vivo was investigated by analyzing short‐term antigen‐specific CD4+ T cell clones and single CD4+ T cells derived from draining lymph nodes of mice undergoing a T helper 2 (Th2)‐like response to keyhole limpet hemocyanin (KLH). On average, 2.7% of CD4+ lymph node cells gave rise to clones in the presence of the immunizing antigen and, of these, about 90% secreted interleukin‐4 (IL‐4) and 20% secreted interferon‐γ (IFN‐γ) when restimulated after 2 weeks in vitro. Almost all IFN‐γ‐producing clones co‐produced IL‐4. The definition of clones as positive or negative for cytokine synthesis depended on assay sensitivity, however, since their titers were distributed continuously from the threshold of detection over at least a 1000‐fold range.Reverse‐transcription polymerase chain reaction analysis of 59 clones revealed multiple patterns of co‐expression of IL‐2, IL‐3, IL‐4, IL‐6, IFN‐γ and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) mRNA. Although most clones contained detectable IL‐4 and IL‐6 mRNA and a minority contained IFN‐γ mRNA, only 1 clone expressed the canonical Th2 cytokine profile. The observed frequencies of mRNA co‐expression for most of the six cytokines (including IL‐4 with IFN‐γ), and the frequency of co‐secretion of IL‐4 and IFN‐γ, were not significantly different from those predicted for random association. Independent regulation of IL‐4 and IFN‐γ mRNA expression was confirmed at the single‐cell level in a polyclonal population of KLH‐primed CD4+ cells, among which co‐expression of these cytokines again occurred at the frequency predicted for a random event. The data suggest that the polarization of this immune response towards a Th2 cytokine profile is achieved by altering the probabilities of expression of the IL‐4, IFN‐γ and other cytokine genes at the population level, rather than by selective expansion of a distinct T cell subset.
Biphasic effect of interferon‐γ in murine collagen‐induced arthritis
Authors: Boissier Marie‐Christophe , Chiocchia Gilles , Bessis Natacha , Hajnal Julia , Garotta Gianni , Nicoletti Ferdinando , Fournier Catherine 
Published: March 2007

AbstractInterferon‐γ (IFN‐γ) exerts both enhancing and suppressing influences on collagen‐induced arthritis (CIA), depending on the route and protocol of administration. To study the role of IFN‐γ on the autoimmune process of CIA, we treated DBA/1 mice with two different rat monoclonal antibodies (mAb) to murine IFN‐γ. Treatments, given twice weekly for 4 weeks, consisted of intraperitoneal injections of either mAb. In early treatments, starting from the day of immunization with type II collagen (CII), the severity of arthritis was reduced in both groups of anti‐IFN‐γ‐treated mice compared with control groups. Moreover, anti‐CII antibody levels decreased in the sera of these mice. CIA was also down‐regulated in mice treated from days 14 or 28 post immunization. In contrast, late treatments with anti‐IFN‐γ mAb either induced aggravating effects, or did not affect the course of the disease. On the other hand, administration of high doses (8 × 104 U three times/week) of rat recombinant IFN‐γ exerted a transient increase of CIA severity. These findings suggest that IFN‐γ may play a critical role during both the induction and the course of CIA, first enhancing the immune response, and then regulating the arthritis process.
Orally induced bystander suppression in experimental autoimmune uveoretinitis occurs only in the periphery and not in the eye
Authors: Wildner Gerhild , Thurau Stephan R. 
Published: March 2007

AbstractOral administration of retinal soluble antigen (S‐Ag) suppresses the induction of S‐Ag‐mediated experimental autoimmune uveitis (EAU) in Lewis rats. EAU induced with interphotoreceptor retinoid‐binding protein (IRBP), another retinal autoantigen, can also be suppressed by oral administration of IRBP. It has been speculated that feeding with one retinal autoantigen could suppress induction of uveitis with the other retinal protein by means of bystander suppression. Both uveitogenic effector and suppressor cells should find their antigens within the retina, where the suppressor cells would be expected to act on the effector cells. However, reciprocal combinations of antigens used for induction and suppression of uveitis failed to prevent onset of disease, demonstrating that bystander suppression obviously does not occur in the eye. To investigate further the localization of suppressor mechanisms, we fed Lewis rats either with retinal S‐Ag or with ovalbumin (OVA) and then immunized the animals either with a mixture of S‐Ag and OVA or with each antigen separately, injected into contralateral hind legs. Feeding of S‐Ag prior to immunization led to suppression of uveitis, whereas feeding of OVA had no tolerizing effect when S‐Ag and OVA were injected into different legs. Nevertheless, immunizing rats with a mixture of S‐Ag and OVA after OVA feeding suppressed uveitis to a high degree. These findings suggest that orally induced bystander suppression might not occur in the target organ, but rather peripherally at the site of induction of the autoimmune T cells.
Toxoplasma gondii‐specific CD4+ T cell clones from healthy, latently infected humans display a ThO profile of cytokine secretion
Authors: Prigione Ignazia , Facchetti Paola , Ghiotto Fabio , Tasso Paola , Pistoia Vito 
Published: March 2007

AbstractHuman Toxoplasma gondii (Tg)‐specific T cell clones were raised by infecting peripheral blood mononuclear cells (MNC) from two healthy, latently infected individuals with Tg trophozoites. All of the clones had a CD4+ immunophenotype and produced simultaneously interleukin (IL)‐2, interferon (IFN)‐γ, IL‐4 and IL‐5 upon mitogen or antigen stimulation. Tg‐specific T cell clones were classified as T helper of type 0 (ThO) since most of them released roughly comparable amounts of IFN‐γ and IL‐4. In some clones, a trend to an increased production of IFN‐γ following antigen‐specific as compared to non‐specific stimulation was observed. The ThO phenotype was also expressed by T cell clones that had been raised from bulk cultures performed in the presence of IL‐4 or IFN‐γ. All of the Tg‐specific T cell clones were cytolytic in a non‐specific assay which involves the triggering of the CD3‐T cell receptor (TcR) complex. Some clones specifically lysed an autologous lymphoblastoid cell line (LCL) that had been infected with Tg trophozoites. Finally, most of the Tg‐specific T cell clones produced IL‐10, irrespective of whether they had been raised from bulk cultures incubated in the presence or absence of IL‐4 or IFN‐γ. Taken together, these findings suggest that Tg‐specific ThO helper cell clones from healthy, latently infected individuals, beside activating toxoplasmacidal mechanisms through IFN‐γ release, might limit the magnitude of the immune response to the parasite by killing Tg‐infected antigen‐presenting cells and by releasing IL‐10.
An interleukin‐6 transgene expressed in B lymphocyte lineage cells overcomes the T cell‐dependent establishment of normal levels of switched immunoglobulin isotypes
Authors: Oka Yoshihiro , Rolink Antonius G. , Suematsu Sachiko , Kishimoto Tadamitsu , Melchers Fritz 
Published: March 2007

AbstractLong‐term proliferating, stromal cell/interleukin (IL)‐7‐reactive precursor B cell lines established from fetal liver and bone marrow of human IL‐6‐transgenic B6Ld46 mice produce and secrete human IL‐6. When transplanted into severecombined immunodeficient (SCID) or Rag2 knockout (Rag2‐T) mice, these pre‐B cell lines establish a part of the B cell compartment but yield no T cells, as do pre‐B cell lines from genetically matched non‐transgenic mice. Within 2 to 3 months after transplantation, the serum of mice transplanted with pre‐B cells from normal mice contains normal levels of IgM (200–600 μg/ml) but 10–100‐fold lower levels of the IgG subclasses and of IgA. In contrast, the sera of mice transplanted with IL‐6 transgenic pre‐B cells contain not only IgM, but also IgG and IgA at nearly normal levels. The results indicate that at least a part of the plasmacytosis and elevated IgG production observed previously in the IL‐6‐transgenic mice appears to be due to a T cell‐independent activation of IgG and IgA production by the IL‐6‐secreting pre‐B cells and their differentiated progeny in the immunodeficient hosts.
Signaling through murine CD38 is impaired in antigen receptor‐unresponsive B cells
Authors: Lund Frances E. , Solvason Nanette W. , Cooke Michael P. , Heath Andrew W. , Grimaldi J. Christopher , Parkhouse R. M. E. , Goodnow Christopher C. , Howard Maureen C. 
Published: March 2007

AbstractCD38 is a 42‐kDa membrane associated enzyme which converts NAD into cyclic ADP‐ribose (cADPR), a Ca2+‐mobilizing second messenger, and ADP‐ribose (ADPR). Agonistic antibodies to murine CD38 deliver a potent growth co‐stimulus to mature splenic B lymphocytes. In this report we demonstrate a striking relationship between CD38‐mediated mitogenesis and the ability of surface IgM to promote B cell proliferation. Tolerized B lymphocytes obtained from a double‐transgenic mouse model of B cell tolerance do not proliferate in response to antigen stimulation through the Ig receptor or to agonistic anti‐CD38 antibodies. Similarly, B‐1 cells isolated from the peritoneal cavity of normal mice, and splenic B cells isolated from newborn mice were also unresponsive to both anti‐IgM and anti‐CD38 stimulation. All of these CD38‐unresponsive B cells expressed normal levels of cell surface CD38 and responded to numerous other stimuli. CD38 immunoprecipitated from these B cell populations was normal in size and effectively hydrolyzed NAD, suggesting that the defect in CD38 signaling likely occurs downstream of CD38 itself. Signaling through CD38 and IgM does not always have identical effects on B cells since anti‐CD38 cannot deliver inhibitory growth or differentiation signals to normal B cells or immature B cell lines. Nevertheless, the correlative data with these multiple B cell models of unresponsiveness suggests that the signaling pathway utilized by CD38 and IgM intersect, possibly sharing at least one of the crucial components of the Ig receptor signaling cascade.
Increased dexamethasone sensitivity of neonatal leukocytes: different mechanisms of glucocorticoid inhibition of T cell proliferation in adult and neonatal cells
Authors: Kavelaars Annemieke , Zijlstra Jitske , Bakker Joost M. , Van Rees Emmelien P. , Visser Gerard H. A. , Zegers Ben J. M. , Heijnen Cobi J. 
Published: March 2007

AbstractGlucocorticoids (GC) are known to inhibit the proliferative response of leukocytes after mitogenic activation. Until now, the effects of GC on the immune system have been studied predominantly in adults. However, GC are frequently administered to human fetuses and newborns for the prevention and treatment of respiratory distress syndrome. The immune system of human newborns is still a functionally immature system. Therefore, we wondered whether the immaturity is also reflected by altered responses to hormonal signals such as glucocorticoids. We studied the effects of the GC dexamethasone (DEX) on the proliferation of peripheral blood mononuclear cells and T cells in vitro after stimulation with phytohemagglutinin, anti‐CD3, anti‐CD3/anti‐CD28 or anti‐CD2/anti‐CD28. Our data demonstrate that neonatal cells are much more sensitive to inhibition of the proliferative response by DEX than adult cells (ED50 1 ± 0.8 nM vs. 221 ± 135 nM). This difference in sensitivity is not related to differences in affinity and capacity of binding of [3H] DEX. Moreover, we show that the mechanisms of GC inhibition differ between adult and neonatal cells. In adult cells, addition of interleukin (IL)‐2 does not restore DEX inhibition of the proliferative response. In contrast, the proliferative response of neonatal cells can be restored completely by the addition of IL‐2. These data suggest that the primary target of GC in neonatal cells is inhibition of IL‐2 production. In adult cells, other mechanisms are responsible for inhibition of T cell proliferation.
Role of T helper cell precursor frequency on vesicular stomatitis virus neutralizing antibody responses in a T cell receptor β chain transgenic mouse
Authors: Freer Giulia , Burkhart Christoph , Rülicke Thomas , Ghelardi Emilia , Rohrer Urs Hoffmann , Pircher Hanspeter , Zinkernagel Rolf M. , Hengartner Hans 
Published: March 2007

AbstractDuring most immune responses, T cells help antigen‐specific B cells to make antibodies against the antigen. One of the contributions of T cells to antibody production is the induction of isotype switching from IgM to IgG, which is the most abundant isotype in blood serum during recall responses. Other features of memory responses are faster kinetics and higher titers of antibody in the serum. What causes a primary immune response to be different from a secondary is not yet very clear and, particularly, the influence of precursor frequencies of T and B cells on memory responses still remains to be answered. To address this issue, a transgenic (tg) mouse line (ADA) was developed; it expresses the β chain (Vβ2) of a major histocompalibility complex class II‐restricted T cell receptor (TcR) specific for the glycoprotein (G) of vesicular stomatitis virus (VSV) serotype Indiana (VSV‐IND). These mice exhibit an increased precursor frequency of VSV‐specific CD4+ T cells that leads to enhanced neutralizing IgG production against VSV in vivo in unprimed mice. The data indicate that increased frequency of naive specific helper T cells alone may account for features of a memory phenotype such as high titer of antibodies and isotype switching.
Antibody responses to Toxoplasma gondii antigen in human peripheral blood lymphocyte‐reconstituted severe‐combined immunodeficient mice reproduce the immunological status of the lymphocyte donor
Authors: Walker William , Roberts Craig W. , Brewer James M. , Alexander James 
Published: March 2007

AbstractThese studies describe the production of specific antibodies in human peripheral blood lymphocyte‐reconstituted severe‐combined immunodeficient (PBL‐SCID) mice following vaccination with antigen from the protozoan parasite Toxoplasma gondii. To determine the effect of previous exposure of the lymphocyte donor to antigen, human‐PBL‐SCID animals were created by transferring peripheral blood lymphocytes from either a single T. gondii‐seronegative or a single seropositive donor. These reconstituted animals were subsequently inoculated with T. gondii soluble tachyzoite antigen (STAg) entrapped within non‐ionic surfactant vesicles as an immunological adjuvant. Animals were bled at pre‐determined time points post‐vaccination and the expression of human anti‐STAg antibodies in the plasma determined by enzyme‐linked immunosorbent assay. Human antibodies specific for STAg were readily inducible in both groups of reconstituted animals, although the pattern of isotype production differed markedly between groups. The response in animals reconstituted with lymphocytes from the T. gondii‐seronegative donor consisted primarily of IgM and subsequently of IgG (predominantly IgG1). In animals reconstituted with lymphocytes from the seropositive donor, no parasite‐specific IgM could be demonstrated. The detectable response to STAg consisted entirely of human antibodies of the IgG isotype (IgG1), indicative of a memory‐type response. These results mimicked exactly the antibody responses that would be expected had the lymphocyte donors been directly challenged with either the antigen or the live infectious agent, demonstrating that the immune system within these animals is functional and reproducible with regard to both the primary and secondary responses of the human donors.
The role of γδ T cells in priming macrophages to produce tumor necrosis factor‐α
Authors: Nishimura Hitoshi , Emoto Masashi , Hiromatsu Kenji , Yamamoto Shunsuke , Matsuura Keiko , Gomi Hiroshi , Ikeda Toshio , Itohara Shigeyoshi , Yoshikai Yasunobu 
Published: March 2007

AbstractThe secretion of tumor necrosis factor (TNF)‐α from macrophages is regulated by both priming and triggering signals. We found that macrophages from mice lacking γδ T cells [T cell receptor (TCR) δ−/‐ mice], which lack the gene encoding the δ chain, produced only small amounts of TNF‐α in response to lipopolysaccharide (LPS) and showed a reduced level of expression of CD14. Pre‐incubation of macrophages from TCR δ‐/‐ mice with γδ T cells from their TCR δ+/‐ littermates restored their capacity to produce TNF‐α in response to LPS. The priming activity of γδ T cells was in part inhibited by neutralizing anti‐interferon (IFN)‐γ monoclonal antibodies. Collectively, these results suggest that γδ T cells play a role in priming macrophages to a steady state of activation via IFN‐γ secretion, which allows them to produce TNF‐α when exposed to LPS.
CD38 ligation induces discrete cytokine mRNA expression in human cultured lymphocytes
Authors: Ausiello Clara M. , Urbani Francesca , la Sala Andrea , Funaro Ada , Malavasi Fabio 
Published: March 2007

AbstractHuman CD38 is a surface glycoprotein expressed by different immuno‐competent cells such as immature and activated lymphocytes, plasma cells and natural killer cells. It has recently been reported that the CD38 molecule exerts adenosine diphosphate ribosyl cyclase activity and is associated with distinct transmembrane signaling molecules. This study reports that ligation of CD38 by specific monoclonal antibodies (mAb) induces multiple cytokine mRNA expression in cultured peripheral blood mononuclear cells (PBMC). The mRNA for tumor necrosis factor‐α, interleukin (IL)‐1β, IL‐6, granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and IL‐12 were always detected, whereas interferon‐γ and IL‐10 mRNA expression were seen in most, but not all PBMC cultures. Low levels of IL‐2, IL‐4 and IL‐5 mRNA were also found. The key observation of this work is that CD38 ligation in PBMC induces a large spectrum of cytokines, many of which overlap with those induced via CD3 activation. The main differences between CD38 and CD3 activation are the low to undetectable levels of IL‐2 mRNA, and the sustained IL‐1β and IL‐6 mRNA accumulation found in PBMC cultures following treatment with anti‐CD38 mAb. Furthermore, PBMC proliferation was not found to be a prerequisite for CD38‐mediated cytokine induction. Together, these results suggest that human CD38 activates a signaling pathway which leads to the induction of a discrete array of cytokines, and that this pathway only partially overlaps with that controlled by T cell receptor CD3.
Covalent linkage of C3 to properdin during complement activation
Authors: Whiteman Leslie Y. , Purkall Donald B. , Ruddy Shaun 
Published: March 2007

AbstractActivation of the alternative complement pathway of serum produces complexes of properdin (P) and C3 as measured in a double antibody enzyme‐linked immunosorbent assay. When purified from serum, these complexes decrease factor B hemolytic activity in serum and do not restore the alternative pathway hemolytic activity of serum deficient in P. Sodium dodecylsulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE) of activated serum containing biotinylated P, followed by blotting to nitrocellulose and development with streptavidin‐alkaline phosphatase revealed a band at 53 kDa for monomeric P and an additional band at 160 kDa. P samples eluted from zymosan and purified from activated serum revealed a band at 116 kDa for C3α and 74 kDa for C3β, and an additional band at 160 kDa when analyzed by SDS‐PAGE, Western blotting and development with antibody to C3. The appearance of a 160 kDa band containing P and C3 indicates that these proteins are contained in a complex formed during activation of the alternative pathway. Activation of a purified reagent mixture containing factors B, D, and H, and 125I‐labeled P or 125I‐labeled C3, followed by SDS‐PAGE and autoradiography confirmed the presence of a 160‐kDa band which disappeared following hydroxylamine treatment of the sample. These data are consistent with a covalent linkage of C3 to P via the C3α chain, producing the 160‐kDa complex.
Selective variations in vivo of VH3 and VH1 gene family expression in peripheral B cell IgM, IgD and IgG during HIV infection
Authors: David Denis , Demaison Christophe , Bani Lynda , Zouali Moncef , Thèze Jacques 
Published: March 2007

AbstractWe have analyzed the expression of VH gene families in IgM, IgD and IgG of peripheral blood B cells from a group of HIV‐infected patients. CD19+CD20+ cells were purified and anchored reverse transcriptase‐polymerase chain reaction products were hybridized with VH gene family probes. IgM, IgD and IgG that expressed a VH3 gene family segment, were decreased in patients with low CD4 counts and to a greater extend in patients with AIDS symptoms (up to 85% for IgG) compared to adult healthy donors. This was correlated with elevated levels of IgM and IgG encoded by a VH1 gene family segment (around 60% for IgG). These results confirm and extend previous work that has detected the VH3 gene family under‐representation in HIV infection. Here, we show that, in vivo, this phenomenon actually affects the different B cell populations of the peripheral blood: IgM+ or IgG+ B cells and also IgM+IgD+ naive B cells. In the course of HIV infection, this results in their gradual depletion. Data presented here strengthen the hypothesis that a B cell superantigen exists in HIV infection. These pronounced variations of the normally most‐expressed VH gene family may be related to B cell abnormalities detected in HIV‐infected patients.