EJI is an immunology research journal, focusing on various aspects of immunology including, but not limited to: Basic: Adaptive immunity, Innate immunity, Leukocyte and lymphoid organ ontogeny, Molecular immunology and signaling, New technology, Tissue immunology and leukocyte trafficking Basic/Clinical studies*: Allergy and inflammation, Immunity to infection, Immunodeficiencies and autoimmunity, Transplantation and tolerance, Immunomodulation and Immune Therapies, Tumor immunology *Clinical studies EJI's editorial team understands the experimental restrictions of clinical/human studies. EJI considers descriptive clinical papers without a mechanism, provided that the studies are hypothesis-driven with a clear rationale and informative results that forward our understanding of immunological processes and disease.
Geoffrey L. Stephens, Qun Wang, Bonnie Swerdlow, Geetha Bhat, Roland Kolbeck, Michael Fung
The aryl hydrocarbon receptor (AhR) is a key transcriptional regulator of Th17‐cell differentiation. Although endogenous ligands have yet to be identified, evidence suggests that tryptophan metabolites can act as agonists for the AhR. Tryptophan metabolites are abundant in circulation, so we hypothesized that cell intrinsic factors might exist to regulate the exposure of Th17 cells to AhR‐dependent activities. Here, we find that Th17 cells preferentially express kynurenine 3‐monooxygenase (KMO), which is an enzyme involved in catabolism of the tryptophan metabolite kynurenine. KMO inhibition, either with a specific inhibitor or via siRNA‐mediated silencing, markedly increased IL‐17 production in vitro, whereas IFN‐γ production by Th1 cells was unaffected. Inhibition of KMO significantly exacerbated disease in a Th17‐driven model of autoimmune gastritis, suggesting that expression of KMO by Th17 cells serves to limit their continuous exposure to physiological levels of endogenous AhR ligands in vivo.
AbstractThe extent to which B cells newly formed in the bone marrow contribute to primary and secondary B cell responses was investigated. This was assessed by constructing chimeras between congenic strains of rats differing in their kappa light chain allotype. Recipient animals received 800 cGy whole body irradiation with hind limb shieldin to protect a proportion of their hemopoietic capacity. These rats then received 3 × 108 kappa allotype‐marked thoracic duct lymphocytes from donors previously immunized twice with either dinitrophenylated spider crab (Maia squinada) hemocyanin (DNP‐MSH) or MSH alone. The chimeras were immunized with DNP‐MSH and the production of anti‐DNP antibody of both donor and host origin was measured. In the period immediately after immunization both newly formed host virgin B cells and donor memory B cells gave rise to substantial proportions of the anti‐DNP antibody. After this initial period, antibody production became sustained by activation of memory B cells only. The chimeras were reimmunized with DNP‐MSH at 32 days after their first immunization. There was again evidence of a brief period of both virgin and memory B cell activation followed by memory B cell activation only. Donor B cell clones remained dominant in the established response throughout the 5 months each chimera was studied. The data are interpreted as indicating two phases of B cell activation. It is suggested that the first phase where both virgin and memory B cells are activated may be associated with antigen presentation on dendritic or interdigitating cells outside follicles. It is argued that the second phase where only memory B cells are activated is more likely to be associated with antigen on follicular dendritic cells.
AbstractThe adoptive secondary response of mice to conjugates of NIP (4‐hydroxy‐5‐iodo‐3‐nitro‐phenacetyl‐) and DNP (2,4‐dinitrophenyl‐) is here used to elucidate the mechanism of cellular cooperation. The framework into which the experiments fit can be formulated as follows. Priming immunization raises a crop not only of specific antibody‐forming‐cell‐precursors (AFCP) but also of specific helper cells. Upon secondary stimulation the helper cells serve a role as handlers or concentrators of antigen, thus enabling AFCP which would otherwise be incapable of reacting to initiate antibody synthesis. In this act of cooperation both cells recognise antigen; in the system examined here the helpers recognise carrier determinants and the AFCP recognise either the hapten or other carrier determinants.The first aim of the experiments was to raise populations of helpers and AFCP of distinguishable specificity. Mice were primed with NIP‐Ovalbumin (OA) mixed with chicken γ‐globulin (CGG) and bovine serum albumin (BSA); in comparison with controls primed with unmixed NIP‐OA, their cells after transfer were relatively more sensitive to secondary stimulation with NIP‐CGG or NIP‐BSA and similar findings were obtained in cross‐checks of these carriers. For reasons which are not entirely clear, non‐transferred cells did not show the same effect. In further experiments cells primed with one conjugate (e. g. NIP‐OA) were mixed with cells primed with another protein (e. g. BSA), transferred and challenged with the hapten conjugated to the second protein (i. e. NIP‐BSA). In comparison with controls lacking the protein‐primed cells, the mixture regularly showed greater sensitivity to stimulation. NIP and DNP were tested in many of the possible combinations with BSA, OA and CGG with the same result. The mixture system was used in the further analysis.Tests with allotype‐marked protein‐primed cells showed that these cells did not participate in the production of the anti‐hapten antibody and could therefore properly be regarded as helpers. Tests of specificity showed that physical union of the hapten and carrier were required: cells primed with BSA, for example, would not help NIP‐OA‐primed cells to make a response to NIP‐HSA even when stimulated at the same time with BSA. Transfer of less than one‐tenth of the spleen gives a maximum helper effect, whereas AFCP activity continues to rise as larger numbers of cells are transferred. Helper cells are therefore normally present in excess.Helper activity is more resistant than AFCP activity to irradiation, drugs and semi‐allogeneic cell transfer across an H‐2 barrier. This suggests that helper cells play a relatively passive role in the immune response.Several observations indicate that helper cells are thymus‐derived mediators of cellular immunity. Passively transferred antibody did not substitute for helper cells. After immunization helper activity developed faster than AFCP activity. Spleen cells obtained from lethally‐irradiated, thymocyte‐repopulated, immunized donors provided help. Cells from the thymus‐derived fraction of thymus/marrow chimeras also appear to provide help.Thus, the hapten‐carrier cooperative response maps onto the well‐established synergy of thymus and marrow in the response to foreign erythrocytes.
Xin Chen, Robin Winkler-Pickett, Nicholas H. Carbonetti, John R. Ortaldo, Joost J. Oppenheim, O. M. Zack Howard
AbstractWe observed a remarkable reduction in the frequency and immunosuppressive activity of splenic CD4+CD25+ T cells in C57BL/6 mice with MOG33–55‐induced experimental autoimmune encephalomyelitis (EAE). Our study revealed that pertussis toxin (PTx), one component of the immunogen used to induce murine EAE, was responsible for down‐regulating splenic CD4+CD25+ cells. Treatment of normal BALB/c mice with PTx in vivo reduced the frequency, suppressive activity and FoxP3 expression by splenic CD4+CD25+ T cells. However, PTx treatment did not alter the expression of characteristic phenotypic markers (CD45RB, CD103, GITR and CTLA‐4) and did not increase the expression of CD44 and CD69 by the residual splenic and lymph node CD4+CD25+ T cells. This property of PTx was attributable to its ADP‐ribosyltransferase activity. PTx did not inhibit suppressive activity of purified CD4+CD25+ T regulatory (Treg) cells in vitro, but did so in vivo, presumably due to an indirect effect. Although the exact molecular target of PTx that reduces Treg activity remains to be defined, our data suggests that alteration of both distribution and function of splenic immunocytes should play a role. This study concludes that an underlying cause for the immunological adjuvanticity of PTx is down‐regulation of Treg cell number and function.
Claudio Franceschi, Andrea Cossarizza, Daniela Monti, Enzo Ottaviani
AbstractThe hypothesis that natural killer (NK) cells represent an important form of cell recognition and cytotoxicity leads to the prediction that NK‐like activity should be preserved throughout phylogenetic development. This was tested in the invertebrate Planorbarius corneus. Two types of cells can be identified and separated from the hemolymph of this mollusc, i.e. glass‐adherent macrophage‐like spreading hemocytes (SH) and nonadherent round hemocytes (RH). Only RH are able to lyse the K‐562 human target cell line in a short‐term NK cytotoxicity test. This NK‐like activity, severely reduced after 18 h incubation at 24 °C, is preserved by human recombinant interleukin 2. A further analysis of P. corneus hemocytes has been performed by using several mouse anti‐human monoclonal antibodies and cytofluorimetric analysis. Unexpectedly, both SH and RH react with several monoclonal antibodies, including those directed against epitopes typical of mammalian NK cells and cell adhesion molecules. On the whole, these data support the hypothesis that a primitive NK‐like activity appeared early in evolution and is not shared by phagocytic cells.
Zvi H. Marcus, Y. Soffer, Alon Ben‐David, Sarah Peleg, L. Nebel
AbstractDelayed hypersensitivity to human and guinea pig sperm was demonstrated in guinea pigs of the Rockefeller strain by immunization with H37Ra adjuvant. The reaction in vivo was demonstrated by skin testing the animals and in vitro by the capillary method. It was found that the sensitivity is not only directed towards the sensitizing antigen, but also shows cross‐reactivity. Thus, peritoneal exudate cells derived from guinea pigs sensitized to human sperm were inhibited by guinea pig sperm. This cross‐reactivity revealed the possibility of a tissue specific antigen. In addition, supernatants obtained after incubation of the sensitized lymph node cells with the specific antigen were found to be spermatotoxic.
Paola Zaccone, Zoltán Fehérvári, Frances M. Jones, Stéphane Sidobre, Mitchell Kronenberg, David W. Dunne, Anne Cooke
AbstractInfection with Schistosoma mansoni (S. mansoni) or exposure to eggs from this helminth inhibits the development of type 1 diabetes in NOD mice. In this study we show that soluble extracts of S. mansoni worm or egg completely prevent onset of type 1 diabetes in these mice but only if injection is started at 4 weeks of age. T cells from diabetes‐protected mice make IL‐10 in recall responses to parasite antigens. These cells are furthermore impaired in their ability to transfer diabetes to NOD‐SCID recipients. Bone marrow dendritic cells derived from NOD mice are found to make more IL‐10 and less IL‐12 following culture with S. mansoni soluble egg antigens in conjunction with lipopolysaccharides. NOD mice are deficient in NKT cells. Soluble worm and egg antigens increase the numbers of Vα14i NKT cells in NOD mice. These effects of schistosome antigens on the innate immune system provide a mechanism for their ability to prevent type 1 diabetes in NOD mice.
Ioannis Vouldoukis, Pierre‐André Bécherel, V. Riveros‐Moreno, Michel Arock, Otamires Da Silva, Patrice Debré, Dominique Mazier, M. Djavad Mossalayi
AbstractThe host response to Leishmania infection is regulated by a specific pattern of local cytokine production. We investigated the effect of interleukin (IL)‐10 and IL‐4 on the leishmanicidal activity of human macrophages (Mϕ). As with L. major, intracellular killing of L. infantum by human Mϕ was obtained following ligation of surface CD23 or cell treatment with Interferon‐γ (IFN‐γ). This leishmanicidal activity required nitric oxide (NO) generation by activated Mϕ, and it was partially mimicked by cell treatment with chemical NO donors. Addition of recombinant human IL‐10 or IL‐4 to CD23 mAb or IFN‐γ decreased L. infantum and L. major killing by infected Mϕ. IL‐10 was more potent than IL‐4 in inhibiting the leishmanicidal activity of human Mϕ. Inhibition of Leishmania killing by IL‐4 and IL‐10 correlated with decreased NO generation from Mϕ, and was reversed when exogenous NO was added to cell cultures. Therefore, IL‐10 and IL‐4 down‐regulate leishmanicidal activity of human Mϕ, in part by inhibiting NO generation by these cells.
Hubertine Heremans, Chris Dillen, Marleen Groenen, Erik Martens, Alfons Billiau
AbstractExperimental autoimmune encephalomyelitis (EAE) is a T cell‐mediated inflammatory and demyelinating disorder of the central nervous system. Depending on the experimental conditions, it takes an acute monophasic or a chronic relapsing‐remitting course. We have previously reported that the incidence and severity of acute EAE in mice are reduced by administration of interferon (IFN)‐γ and augmented by treatment with neutralizing antibodies against IFN‐γ. Here, we investigated the role of IFN‐γ in chronic relapsing models of EAE (CREAE) in SJL/J and Biozzi ABH mice. Spontaneous relapses in Biozzi mice as well as induced relapses in SJL/J mice were facilitated by administration of neutralizing monoclonal antibody (mAb) against IFN‐γ in the disease‐free interval. The enhancing effect of anti‐IFN‐γ mAb given before and during the primary attack did not carry over to the relapses. However, early administration of IFN‐γ in Biozzi mice, which developed spontaneous relapses in a high proportion, provided partial protection not only against the first attack, but also against subsequent relapses. Administration of exogenous IFN‐γ during the remission phase provided some protection against subsequent relapses. These results indicate that in both types of relapses, IFN‐γ is produced and does provide a certain degree of protection against disease progression.
Elisa Monzón‐Casanova, Kirsty J. Bates, Christopher W. J. Smith, Martin Turner
AbstractThe maturation of immature B cells and the survival of mature B cells is stringently controlled to maintain a diverse repertoire of antibody specificities while avoiding self‐reactivity. At the molecular level this is regulated by signaling from membrane Ig and the BAFF‐receptor that sustain a pro‐survival program of gene expression. Whether and how posttranscriptional mechanisms contribute to B cell maturation and survival remains poorly understood. Here, we show that the polypyrimidine tract binding proteins (PTBP) PTBP1 and PTBP3 bind to a large and overlapping set of transcripts in B cells. Both PTBP1 and PTBP3 bind to introns and exons where they are predicted to regulate alternative splicing. Moreover, they also show high‐density of binding to 3’ untranslated regions suggesting they influence the transcriptome in diverse ways. We show that PTBP1 and PTBP3 are required in B cells beyond the immature cell stage to sustain transitional B cells and the B1, marginal zone and follicular B cell lineages. Therefore, PTBP1 and PTBP3 promote the maturation of quiescent B cells by regulating gene expression at the posttranscriptional level.
Chỉ số ảnh hưởng
Total publication
221
Total citation
36,278
Avg. Citation
164.15
Impact Factor
0
H-index
99
H-index (5 years)
99
i10
218
i10-index (5 years)
3
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