IFN-γ Synthesis Research Articles

Early IFN-gamma production after YF 17D vaccine virus immunization in mice and its association with adaptive immune responses.

Yellow Fever vaccine is one of the most efficacious human vaccines ever made. The vaccine (YF 17D) virus induces polyvalent immune responses, with a mixed TH1/TH2 CD4+ cell profile, which results in robust T CD8+ responses and high titers of neutralizing antibody. In recent years, it has been suggested that early events after yellow fever vaccination are crucial to the development of adequate acquired immunity. We have previously shown that primary immunization of humans and monkeys with YF 17D virus vaccine resulted in the early synthesis of IFN-γ. Herein we have demonstrated, for the first time that early IFN-γ production after yellow fever vaccination is a feature also of murine infection and is much more pronounced in the C57BL/6 strain compared to the BALB/c strain. Likewise, in C57BL/6 strain, we have observed the highest CD8+ T cells responses as well as higher titers of neutralizing antibodies and total anti-YF IgG. Regardless of this intense IFN-γ response in mice, it was not possible to see higher titers of IgG2a in relation to IgG1 in both mice lineages. However, IgG2a titers were positively correlated to neutralizing antibodies levels, pointing to an important role of IFN-γ in eliciting high quality responses against YF 17D, therefore influencing the immunogenicity of this vaccine.

Preparation of Neomytilan, a Bioglycan from the Mussel Crenomytilus grayanus, and its Immunostimulating Activity

Bioglycans isolated from the Far-East mussel Crenomytilus grayanus were compared analytically. It was found that neomytilan, a bioglycan with reduced protein content, and the previously isolated mytilan stimulated phagocytosis of murine peritoneal macrophages in vitro and influenced the synthesis of pro-inflammatory cytokines TNF-α, IL-6, and IFN-γ.

Dectin-2-Dependent NKT Cell Activation and Serotype-Specific Antibody Production in Mice Immunized with Pneumococcal Polysaccharide Vaccine

Although thymus-independent type 2 antigens generally do not undergo Ig class switching from IgM to IgG, pneumococcal polysaccharide vaccine (PPV) induces the production of serotype-specific IgG. How this happens remains unclear, however. In the present study, PPV immunization induced production of IgG as well as IgM specific for a serotype 3-pneumococcal polysaccharide in the sera of wild-type (WT) mice, but this phenomenon was significantly reduced in Dectin-2 knockout (KO) mice. Immunization with PPV caused IL-12p40 production in WT mice, but this response was significantly reduced in Dectin-2KO mice. Likewise, immunization with PPV activated natural killer T (NKT) cells in WT mice but not in Dectin-2KO mice. Furthermore, administration of α-galactosylceramide, recombinant (r)IL-12 or rIFN-γ improved the reduced IgG levels in Dectin-2KO mice, and treatment with neutralizing anti-IFN-γ mAb resulted in the reduction of IgG synthesis in PPV-immunized WT mice. Transfer of spleen cells from PPV-immunized WT mice conferred protection against pneumococcal infection on recipient mice, whereas this effect was cancelled when the transferred spleen cells were harvested from PPV-immunized Dectin-2KO mice. These results suggest that the detection of PPV antigens via Dectin-2 triggers IL-12 production, which induces IFN-γ synthesis by NKT cells and subsequently the production of serotype-specific IgG.

CD8+ Memory T Cells Appear Exhausted within Hours of Acute Virus Infection

CD8(+) memory T cells are abundant and are activated in a near-synchronous manner by infection, thereby providing a unique opportunity to evaluate the coordinate functional and phenotypic changes that occur in vivo within hours of viral challenge. Using two disparate virus challenges of mice, we show that splenic CD8(+) memory T cells rapidly produced IFN-γ in vivo; however, within 18-24 h, IFN-γ synthesis was terminated and remained undetectable for ≥ 48 h. A similar on/off response was observed in CD8(+) memory T cells in the peritoneal cavity. Cessation of IFN-γ production in vivo occurred despite the continued presence of immunostimulatory viral Ag, indicating that the initial IFN-γ response had been actively downregulated and that the cells had been rendered refractory to subsequent in vivo Ag contact. Downregulation of IFN-γ synthesis was accompanied by the upregulation of inhibitory receptor expression on the T cells, and ex vivo analyses using synthetic peptides revealed a concurrent hierarchical loss of cytokine responsiveness (IL-2, then TNF, then IFN-γ) taking place during the first 24 h following Ag contact. Thus, within hours of virus challenge, CD8(+) memory T cells display the standard hallmarks of T cell exhaustion, a phenotype that previously was associated only with chronic diseases and that is generally viewed as a gradually developing and pathological change in T cell function. Our data suggest that, instead, the "exhaustion" phenotype is a rapid and normal physiological T cell response.

Toll like receptor 2 agonists lipoteichoic acid and peptidoglycan are able to enhance antigen specific IFNγ release in whole blood during recall antigen responses

BackgroundInterferon gamma release assays (IGRA) have been developed to support the diagnosis of diseases like tuberculosis, which lack robust serological test systems. IGRAs focus on cellular immunity especially memory T cells and thus complement serological testing. However, the low frequency of antigen-specific memory T cells in peripheral blood limits IFNγ production to minute amounts and constitutes a major challenge for downstream test systems. We hypothesized that certain toll like receptor (TLR) agonists might enhance IFNγ production in IGRAs after antigen challenge without inducing background cytokine production. In addition, we investigated the potential use of IL2 release after TLR agonist application as another surrogate marker in cytokine release assays. Methods176 healthy controls (HC) were tested for IFNγ- and IL2-secretion in whole blood in the presence of different TLR agonists with and without antigen challenge by ELISA. The selected TLR agonists were lipopolysaccharide (LPS ≙ TLR4), lipoteichoic acid (LTA ≙ TLR2), peptidoglycan (PGN ≙ TLR2), zymosan (Zym ≙ TLR2 and 6), polyinosinic-polycytidylic acid (Poly I:C ≙ TLR3), flagellin (Fla ≙ TLR5), R848 (≙TLR7 and 8), loxoribine (Lox ≙ TLR7) and bropirimine (Bro ≙ TLR7). ResultsTLR2 agonists LTA and PGN increased IFNγ secretion after antigen challenge nearly twofold (740 vs. 443pg/ml for LTA and 969 vs. 469pg/ml for PGN, respectively) without eliciting higher background expression. TLR3 agonist Poly(I:C) and TLR5 agonist Fla also induced a twofold increase in IFNγ synthesis (2.230 vs. 1.085pg/ml for Poly(I:C) and 518 vs. 278pg/ml for Fla, respectively), but background expression was slightly increased (114 vs. 7pg/ml for Poly(I:C) and 47 vs. 12pg/ml for Fla, respectively). IL2 production was not increased after antigen challenge in the presence of LTA, PGN, Poly(I:C) or Fla. The agonists LPS, Zym, R848, Lox and Bro did not raise cytokine synthesis after antigen challenge or they generated high levels of cytokines by themselves. ConclusionOf all tested agonists TLR2-specific LTA and PGN met the requirements to increase IFNγ synthesis in whole blood after challenge with recall antigens without heightening basal cytokine levels alone. Thus, they constitute a potential costimulating reagent for IGRAs. IL2 did not show any potential as a surrogate marker in cytokine release assays in combination with TLR agonists.

Immunological Parameters of the Blood and Monoamine Content in the Brain of Rats during Long-Term Overcrowding

Blood immunological parameters (cytokine profile and interferon status) and the level of monoamines and their metabolites in various brain structures (amygdala, hippocampus, septum, and hypothalamus) were studied in rats kept under standard conditions or in overpopulated cages. Long-term overcrowding was associated with reduced expression of IL-4 gene, increased transcription of IL-17, and decreased production of IFN-γ, which attested to impaired humoral and cell-mediated immunity and disturbances in IFN-γ synthesis at the post-transcriptional level. Under these conditions, the levels of norepinephrine and dopamine decreased in the septum, but increased in the hypothalamus. The amount of dopamine metabolite dihydroxyphenylacetic acid decreased in both these structures, and the index of dopamine metabolism (dihydroxyphenylacetic acid/dopamine ratio, DOPAC/dopamine) decreased only in the hypothalamus. Overcrowding was not followed by changes in the parameters of noradrenergic and dopaminergic systems in the amygdala and hippocampus and serotoninergic system in all study structures.

Virtual memory CD8 T cells display unique functional properties

Previous studies revealed the existence of foreign antigen-specific memory phenotype CD8 T cells in unimmunized mice. Considerable evidence suggests this population, termed "virtual memory" (VM) CD8 T cells, arise via physiological homeostatic mechanisms. However, the antigen-specific function of VM cells is poorly characterized, and hence their potential contribution to immune responses against pathogens is unclear. Here we show that naturally occurring, polyclonal VM cells have unique functional properties, distinct from either naïve or antigen-primed memory CD8 T cells. In striking contrast to conventional memory cells, VM cells showed poor T cell receptor-induced IFN-γ synthesis and preferentially differentiated into central memory phenotype cells after priming. Importantly, VM cells showed efficient control of Listeria monocytogenes infection, indicating memory-like capacity to eliminate certain pathogens. These data suggest naturally arising VM cells display unique functional traits, allowing them to form a bridge between the innate and adaptive phase of a response to pathogens.

RKIP Contributes to IFN-γ Synthesis by CD8+ T Cells after Serial TCR Triggering in Systemic Inflammatory Response Syndrome

Systemic inflammatory response syndrome (SIRS) is associated with the development of severe medical complications, including progression to multiple organ dysfunction syndrome and even death. To date, only marginal improvements in terms of therapeutic options have been established for patients affected by SIRS. Raf kinase inhibitor protein (RKIP) is a regulator of MAPK and NF-κB signaling cascades, which are both critical for production of the proinflammatory cytokines responsible for SIRS initiation. By testing a T cell-dependent mouse model of SIRS that utilizes staphylococcal enterotoxin A specific for Vβ3(+) T cells, we show that RKIP is necessary for the exaggerated production of IFN-γ from SIRS splenocytes. This effect was not due to differences in T cell expansion, IL-10 production, or APC priming, but rather a cell-intrinsic defect lying downstream of the TCR in staphylococcal enterotoxin A-specific CD8(+) T cells. Importantly, mice lacking RKIP were still able to proliferate, survive, and contribute to cytokine production in response to pathogen associated molecular pattern-TLR-mediated stimuli, despite the TCR-dependent defects seen in our SIRS model. Finally, by blocking RKIP in wild-type SIRS splenocytes, the IFN-γ response by CD8(+) Vβ3(+) T cells was significantly diminished. These data suggest that RKIP may be a potential therapeutic target in SIRS by curbing effector cytokine production from CD8(+) T cells during serial TCR triggering.

Reactivity of bovine WC1+ γδ T cells to viral dsRNA (P6107)

Abstract Bovine γδ T cells have properties of both innate and adaptive immune cells. However, detailed studies of how bovine γδ T cells execute their functions as innate or adaptive immune cells are lacking. In addition, their precise role in viral infections of cattle is not known. We have examined the reactivity of bovine γδ T cells to viral dsRNA isolated from bovine respiratory syncytial virus. Viral dsRNA was added to sorted peripheral blood WC1+ γδ T cells or directly delivered into the cells with DOTAP. Cell surface expression of CD80, CD335, MHC I and II, and synthesis of TNFα and IFNγ were investigated following stimulation with viral dsRNA. Addition of viral dsRNA to the culture of γδ T cells does not lead to changes in expression of CD335, MHC I and II but induces increased expression of CD80, although not statistically significant compared to non-stimulated cells. Direct delivery of viral dsRNA into WC1+ γδ T cells by DOTAP induced a twofold increase in expression of CD335 and MHC I with smaller increases in expression of MHC II and CD80. Although WC1+ γδ T cells synthesized low levels of TNFα and IFNγ in the presence of viral dsRNA or not, they significantly increased synthesis of IFNγ upon direct delivery of viral dsRNA into the cells. Results suggest that viral dsRNA may induce expression of molecules that promote innate function of γδ T cells and are discussed in context of pathways for enhancing bovine γδ T cell function against viral infections.

Chromone linked nitrone derivative induces the expression of iNOS2 and Th1 cytokines but reduces the Th2 response in experimental visceral leishmaniasis

In our previous work we have shown that the novel synthetic chromone derivative could effectively inhibit the Leishmania donovani replication in vitro and in vivo with less cytotoxicity on murine splenocytes. The aim of the present study is to explore the possible mechanism of anti-leishmanial effect of C-(6-methyl-4-oxo-4H-1-benzopyran-3-yl)-N-(p-tolyl) nitrone (designated as NP1) in vitro and in vivo in experimental visceral leishmaniasis caused by L. donovani. The cytotoxic effect of this derivative was studied in murine peritoneal macrophages by MTT method. NP1 at a dose of 17.06μM showed 50% inhibition on L. donovani promastigotes but found less cytotoxic to the RAW 264.7 cells. Even the higher concentration of IC50 (up to four fold) did not exert much cytotoxic effect on RAW 264.7. Interestingly, NP1 at lower concentration (8.53μM) could inhibit 50% of intracellular amastigotes in murine peritoneal macrophages. L. donovani is known to exert its pathogenic effects mainly by the suppression of NO generation and subversion of the cellular inflammatory responses in the macrophages. NP1 was found to induce a potent host-protective immune response by enhancing NO generation and iNOS2 expression at mRNA level and by up-regulating proinflammatory cytokines such as IL-12 and IFN-γ and limiting the expression of IL-10 in vivo. The NO dependent killing was further confirmed in iNOS−/− mice compared to wild type. In agreement with the fact, induced synthesis of IL-12 and IFN-γ and associated down-regulation of IL-10 by the treatment of NP1 clearly indicated the possibility of novel strategy of drug development against Leishmania infection.

Overexpression of microRNA-21 is associated with elevated pro-inflammatory cytokines in dominant-negative TGF-β receptor type II mouse

Dominant-negative TGF-β receptor II (dnTGF-βRII) mice spontaneously develop an autoimmune cholangitis resembling human primary biliary cirrhosis (PBC). Interestingly, the dominant-negative TGF-β receptor is expressed by both CD4+ and CD8+ T cells and leads to greatly reduced (but not absent) TGF-β signaling resulting in T cell intrinsic cell mediated autoimmunity. However, the mechanisms of the T cell dysregulation remain unclear. Recently it has been shown that TGF-β signaling is intimately involved with miRNA biogenesis and control. Herein we show that lack of T cell TGF-β signaling leads to down regulation of T cell miRNAs but up-regulation of the key inflammatory miRNA 21. Furthermore, the expression of miR-21 from hepatic effector CD8+ T cells is significantly higher than in the same subsets isolated from spleen and mesenteric lymph nodes of the dnTGF-βRII mice. Previous studies indicate that miR-21 increases the synthesis of IFN-γ and IL-17A by T cells and suppresses apoptosis via programmed cell death protein 4 (PDCD4). Data presented herein demonstrate that transfecting w.t. B6 T cell subsets with miR-21 resulted in up-regulation of the inflammatory cytokines TNF-α and IFN-γ, thus partly replicating the dnTGF-βRII T cell phenotype. In conclusion, these data suggest miR-21 plays a critical role in the production of pro-inflammatory cytokines in dnTGF-βRII mice, which could be a contributing factor for the development of the organ-specific autoimmune cholangitis and colitis in this murine model of human PBC.

Lack of in vitro effect of aglepristone on IFN-γ and IL-4 production by resting and mitogen-activated T cells of luteal bitches

BackgroundAglepristone (RU534) is an antiprogestin used for pregnancy termination, parturition induction and conservative pyometra treatment in bitches. Its molecular structure is similar to mifepristone, an antiprogestin used in human medicine. Mifepristone has been shown to suppress proliferation and cytokine production by T cells, whereas the effect of aglepristone on T cell function remains elusive. The purpose of this project was to investigate the in vitro influence of RU534 on IFN-γ and IL-4 synthesis by peripheral blood T cells isolated from healthy bitches (N = 16) in luteal phase. The peripheral blood mononuclear cells (PBMCs) were incubated with three different dosages of aglepristone, or dimethyl sulfoxide (DMSO), with or without mitogen. The production of cytokines by resting or mitogen-activated T cells was determined by intercellular staining and flow cytometry analysis or ELISA assay, respectively.ResultsOur results showed no statistically significant differences in the percentage of IFN-γ and IL-4-synthesizing CD4+ or CD8+ resting T cells between untreated and aglepristone-treated cells at 24 and 48 hours post treatment. Moreover, mitogen-activated PBMCs treated with RU534 displayed similar concentration of IFN-γ and IL-4 in culture supernatants to those observed in mitogen-activated DMSO-treated PBMCs. Presented results indicate that administration of aglepristone for 48 hours has no influence on IFN-γ and IL-4 synthesis by resting and mitogen-activated T cells isolated from diestral bitches.ConclusionsWe conclude that antiprogestins may differentially affect T cell function depending on the animal species in which they are applied.

DNA vaccine encoding hepatitis C virus proteins NS3-NS5B induces more effective immune response in comparison with DNAs expressing individual nonstructural genes

Event Abstract Back to Event DNA vaccine encoding hepatitis C virus proteins NS3-NS5B induces more effective immune response in comparison with DNAs expressing individual nonstructural genes Olga V. Masalova1*, Ekaterina I. Lesnova1, Alexander V. Ivanov2, Alexey V. Pichugin3, Kristina Y. Permyakova1, Ravshan I. Ataullakhanov3 and Alla A. Kushch1 1 D.I.Ivanovsky Institute of Virology, Russian Ministry of Health, Russia 2 Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Russia 3 Institute of Immunology, Russian Ministry of Health, Russia Currently, there are several DNA vaccines against hepatitis С virus (HCV) being tested, but the optimal composition of HCV genes is not yet defined. The goal of study was to evaluate the effectiveness of genetic immunization of mice with DNA pcNS3-NS5B encoding five hepatitis C virus (HCV) nonstructural proteins: NS3, NS4A, NS4B, NS5A and NS5B in comparison with plasmids containing genes of the same individual nonstructural proteins. The HCV DNA constructions with gene GM-CSF as adjuvant were injected intramuscularly in DBA mice three times. Humoral immune response was assessed with ELISA; cellular immune response - in blast transformation reaction, by quantitation of CD4+ and CD8+ T cell proliferation using flow cytofluorimetry, by intracellular synthesis and secretion of IFN-γ and IL-2 in ELISpot and ELISA. It was found that the functionally active T cell response was achieved to antigens presenting NS3, NS4, NS5A and NS5B epitopes of different HCV genotypes in response to pcNS3-NS5B plasmid and was stronger than that to plasmids carrying individual genes. Injection of pcNS3-NS5B induced high CD4+ Т cells proliferation, IL-2 and IFN-γ secretion, anti-NS3 and anti-NS5B IgG2a production. These findings indicate that genetic immunization with pcNS3-NS5B is promising approach for development of hepatitis C vaccine. Keywords: hepatitis C virus (HCV), nonstructural proteins, DNA immunization, immune response, gene GM-CSF Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Immune-mediated disease pathogenesis Citation: Masalova OV, Lesnova EI, Ivanov AV, Pichugin AV, Permyakova KY, Ataullakhanov RI and Kushch AA (2013). DNA vaccine encoding hepatitis C virus proteins NS3-NS5B induces more effective immune response in comparison with DNAs expressing individual nonstructural genes. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00162 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 11 Mar 2013; Published Online: 22 Aug 2013. * Correspondence: Dr. Olga V Masalova, D.I.Ivanovsky Institute of Virology, Russian Ministry of Health, Moscow, Russia, ol.mas@mail.ru Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Olga V Masalova Ekaterina I Lesnova Alexander V Ivanov Alexey V Pichugin Kristina Y Permyakova Ravshan I Ataullakhanov Alla A Kushch Google Olga V Masalova Ekaterina I Lesnova Alexander V Ivanov Alexey V Pichugin Kristina Y Permyakova Ravshan I Ataullakhanov Alla A Kushch Google Scholar Olga V Masalova Ekaterina I Lesnova Alexander V Ivanov Alexey V Pichugin Kristina Y Permyakova Ravshan I Ataullakhanov Alla A Kushch PubMed Olga V Masalova Ekaterina I Lesnova Alexander V Ivanov Alexey V Pichugin Kristina Y Permyakova Ravshan I Ataullakhanov Alla A Kushch Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

The immunological reactivity of blood cells in early pregnancy for predicting of pregnancy outcomes

The immunological reactivity of blood cells in early pregnancy for predicting of pregnancy outcomes

Evaluation of Immune Responses to Influenza Vaccination in Chronic Obstructive Pulmonary Disease

Background: Given that viral infections are common triggers for exacerbations of Chronic Obstructive Pulmonary Disease (COPD), current clinical guidelines recommend that all patients receive annual influenza vaccinations. A detailed examination of the immune response to vaccination in COPD has not previously been undertaken, so this study aimed to compare immune responses to influenza vaccination between COPD patients and healthy subjects. Methods: Twenty one COPD patients and fourteen healthy subjects were recruited and cellular immune function was assessed pre- and post- vaccination with trivalent inactivated influenza vaccine. Results: One month after vaccination, H1N1 specific antibody titres were significantly lower in COPD patients than in healthy controls (p=0.02). Multivariate analysis demonstrated that post vaccination antibody titres were independently associated with COPD, but not with age or smoking status. Innate immune responses to the vaccine preparation did not differ between the two populations. Serum concentrations of IL-21, a cytokine that is important for B cell development and antibody synthesis, were also lower in COPD patients than in healthy subjects (p<0.01). In vitro functional differences were also observed, with fewer proliferating B cells expressing CD27 (p=0.04) and reduced T-cell IFN-γ synthesis (p<0.01) in COPD patients, relative to healthy subjects. Conclusions: In conclusion, COPD was associated with altered immune responses to influenza vaccination compared to healthy controls with reductions in both T-cell and B-cell function. These findings provide a foundation for future research aimed at optimising the effectiveness of influenza vaccination in COPD.

Pou6f1 is dispensable for mouse T cell development and virus-specific memory CD8+ T cell generation

Event Abstract Back to Event Pou6f1 is dispensable for mouse T cell development and virus-specific memory CD8+ T cell generation Marlene J. Carrasco-Alfonso1*, Wenyu Jiang1 and John Luckey1* 1 Brigham and Women’s Hospital, Harvard Medical School, Department of Pathology, United States Pou6f1 is a POU-domain transcription factor whose paralogs control self-renewal (e.g. Oct-4) and cell fate determination (e.g. Pit-1, Brn3a). It has been shown to be selectively upregulated at the DN3a to DP stages in thymocytes; and across different models in antigen-specific memory/memory-precursors relative to shorter-lived mature CD8+ T lymphocytes. On these bases, we hypothesized that it is required for maintaining a multipotent and/or differentiation-poised state in T cells. To test this, we quantitatively validated its differential expression in lymphocytes, and generated and characterized conditional (Cre/loxP-based) Pou6f1 knockout mice. Germ-line deletion (EIIa-Cre-driven) resulted in viable and fertile progeny with no obvious morphological or behavioral abnormalities. Mice with an early deletion in thymocytes (Lck-Cre-driven) showed normal numbers and phenotype of thymic populations (DN, DP, SP4 and SP8) and peripheral CD4+ and CD8+ T cells, according to the expression of TCRβ, CD3, and activation (CD5, CD44, CD69), differentiation (CD25, CD27, CD28, CD62L, CD122), survival (CD127) and senescence (Klrg1) markers. Likewise, specific deletion in CD8+ cells (E8I/CD8a-Cre-driven) did not affect either antigen-specific CD8+ T cell effector response (ex-vivo OVA-induced IFN-γ synthesis), or memory generation (pentamer binder frequency) and response upon infection with vaccinia-OVA virus. The effects on both memory formation in a competitive adoptive transfer setting and secondary responses are under study. In conclusion, this is the first description of a Pou6f1 knockout mouse. Results to date suggest that Pou6f1 may not be involved in lineage commitment of thymocytes or CD8+ T lymphocytes, or that in the current experimental models its loss is compensated. Keywords: Pou6f1, CD8+ T cell memory, T cell development, POU-domain transcription factor, conditional knockout Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Adaptive Immunity Citation: Carrasco-Alfonso MJ, Jiang W and Luckey J (2013). Pou6f1 is dispensable for mouse T cell development and virus-specific memory CD8+ T cell generation. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.01013 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 Jun 2013; Published Online: 22 Aug 2013. * Correspondence: Dr. Marlene J Carrasco-Alfonso, Brigham and Women’s Hospital, Harvard Medical School, Department of Pathology, Boston, MA, 02115, United States, marleneca@hotmail.com Dr. John Luckey, Brigham and Women’s Hospital, Harvard Medical School, Department of Pathology, Boston, MA, 02115, United States, cluckey@partners.org Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Marlene J Carrasco-Alfonso Wenyu Jiang John Luckey Google Marlene J Carrasco-Alfonso Wenyu Jiang John Luckey Google Scholar Marlene J Carrasco-Alfonso Wenyu Jiang John Luckey PubMed Marlene J Carrasco-Alfonso Wenyu Jiang John Luckey Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Assessment of Cytokine Release After in Vitro Stimulation of Whole Blood with Legionella Pneumophila in Immunocompromised Patients

This study we examined ex vivo potential of the immune response after stimulation of whole blood with L. pneumophila SG 1, SG 2-14 and L. pneumophila standard strain ATCC 33152 in immunocompromised patients, such as: hemodialysis patients and patients after renal transplantation. The levels of TNF-α and IFN-γ in supernatants were measured with the use of commercial ELISA kits. The synthesis of TNF-α and IFN-γ after stimulation with L. pneumophila were analyzed in two aspects: differentiated stimulatory activity in relation to SG 1, SG 2-14 and ATCC 33152 L. pneumophila and differentiated response of the hemodialysis patients and patients after renal transplantation in relation to the control group. The positive and negative results of anti-L. pneumophila antibodies of two groups of our patients were found for the analysis of the stimulatory activity of L.pneumophila as a primary or secondary response. In patients with immunosuppression the response in the secretion of cytokines (TNF-α and IFN-γ) was reduced after stimulation of L. pneumophila SG 1 but in varying degrees after stimulation of L. pneumophila SG 2-14, which indicates that the risk of the infection is varied.

Target-Mediated Disposition Model Describing the Dynamics of IL12 and IFNγ after Administration of a Mifepristone-Inducible Adenoviral Vector for IL-12 Expression in Mice

Interleukin-12 (IL12) is a cytokine with potential applications in the treatment of cancer given the potent immune response that it triggers, in part due to its ability to stimulate expression of interferon-γ (IFNγ). To avoid the toxicity associated with systemic exposure to IL12, a high-capacity adenoviral vector carrying a liver-specific, mifepristone-inducible IL12 expression system (HC-Ad/RUmIL12) has been developed. However, the maintenance of IL12 expression at therapeutic levels is compromised by the inhibitory effect of IFNγ on inducible systems. The aim of this work is to develop a semi-mechanistic model to characterize the relationship between IL12 and IFNγ in wild-type and knock-out mice for the IFNγ receptor treated with HC-Ad/RUmIL12 under different dosing regimens in order to better understand the key mechanisms controlling the system. Rapid binding was considered to account for target-mediated disposition exhibited by both cytokines (equilibrium dissociation constant were 18 and 2.28pM for IL12 and IFNγ, respectively). The final model included: (1) IFNγ receptor turnover, (2) irreversible free cytokine elimination from the serum compartment, (3) internalization of the IL12 receptor complex, (4) IL12 expression upregulated by the co-administration of the adenoviral vector and mifepristone and downregulated by the IFNγ receptor, and (5) synthesis of IFNγ controlled by the relative increments in the bound IL12. In conclusion, a model simultaneously describing the kinetics of IL12 and IFNγ in the context of gene therapy was developed and validated with additional data. The model was applied to design an experimental dosing protocol intended to maintain sustained therapeutic IL12 levels.

Immunization with excreted/secreted proteins in AS/n mice activating cellular and humoral response against Toxoplasma gondii infection

This study investigated how Toxoplasma gondii excretory–secretory antigens (ESA) stimulate the humoral and cellular response in infected hosts. We evaluated IFN-γ, IL-4 TNF-α, and IL-10 levels as well as humoral response of ESA-immunized AS/n mice. T. gondii lysate antigen (TLA), a crude antigen, was used in all experiments to evaluate the immune response. Chronic infected and naive mice were used as control groups, since the immune response is well known. The challenge experiments showed the parasitemia levels, determined by real time PCR and survival index. The naive group had early mortality and higher parasitemia than the ESA-immunized mouse group. In addition the chronic infected group had no parasitemia and mortality. Both ESA-immunized and chronic infected mice produced a similar level of IFN-γ and TNF-α. ESA, also, activated cells from immunized mice to produce IL-4 and IL-10 in lower levels compared to those cells collected from chronic mice but sufficient to modulate IFN-γ and TNF-α synthesis, preventing an excessive immune response that could cause extensive inflammation and host tissue damage. After 6 weeks, ESA-immunized mice had low IgM and IgG2a levels and high IgG1 levels. Purified anti-ESA IgG were able to opsonize tachyzoites (RH strain), and mice that received these parasites had lower parasitemia, and mortality was delayed 48h, compared with the same results from those receiving parasites opsonized with IgG purified from naive mice. The protective immune response in the chronic infection was efficient in protecting the host against infection caused by other T. gondii strain and ESA participate in stimulating the host humoral and cellular responses. The immunization assays showed that ESA can elicit high IgG1, IFN-γ and TNF-α production and, a lower amount of IgM, IgG2, IL-10 and IL-4, suggesting a mixed Th1/Th2 profile.

Supplement of L‐Arg improves protective immunity during early‐stage Plasmodium yoelii 17XL infection

L-arginine (L-Arg), the precursor of nitric oxide (NO), plays multiple important roles in nutrient metabolism and immune regulation. L-Arg supplement serves as a potential adjunctive therapy for severe malaria, because it improves NO bioavailability and reverses endothelial dysfunction in severe malaria patients. In this study, we investigated the effect of dietary L-Arg supplement on host immune responses during subsequent malaria infection using the Plasmodium yoelii 17XL - BALB/c mouse model. We have shown that pretreatment of mice with L-Arg significantly decreased parasitemia and prolonged the survival time of mice after infection. L-Arg supplement led to significant increases in activated CD4(+)T-bet(+)IFN-γ(+) T cells and F4/80(+)CD36(+) macrophages during early-stage infection, which were accompanied by enhanced synthesis of IFN-γ, TNF-α and NO by spleen cells. Moreover, L-Arg-pretreated mice developed more splenic myeloid and plasmacytoid dendritic cells with up-regulated expression of MHC II, CD86 and TLR9. In comparison, L-Arg treatment did not change the number of regulatory T cells and the level of anti-inflammatory cytokine IL-10. Taken together, our results showed that L-Arg pretreatment could improve the protective immune response in experimental malaria infection in mice, which underlines potential importance of L-Arg supplement in malaria-endemic human populations.