ovalbumin and Herpes-Simplex

Cytosolic DNA-mediated activation of the transcription factor IRF3 is a key event in host antiviral responses. Here we found that infection with DNA viruses induced interaction of the metabolic checkpoint kinase mTOR downstream effector and kinase S6K1 and the signaling adaptor STING in a manner dependent on the DNA sensor cGAS. We further demonstrated that the kinase domain, but not the kinase function, of S6K1 was required for the S6K1-STING interaction and that the TBK1 critically promoted this process. The formation of a tripartite S6K1-STING-TBK1 complex was necessary for the activation of IRF3, and disruption of this signaling axis impaired the early-phase expression of IRF3 target genes and the induction of T cell responses and mucosal antiviral immunity. Thus, our results have uncovered a fundamental regulatory mechanism for the activation of IRF3 in the cytosolic DNA pathway.

Topics: Adenoviridae; Animals; Bone Marrow Cells; Cells, Cultured; Cytosol; Dendritic Cells; DNA; HEK293 Cells; Herpes Simplex; Herpesvirus 1, Human; Humans; Immunization; Immunoblotting; Interferon Regulatory Factor-3; Membrane Proteins; Mice, Inbred C57BL; Mice, Knockout; Nucleotidyltransferases; Ovalbumin; Protein Binding; Protein Serine-Threonine Kinases; Ribosomal Protein S6 Kinases, 90-kDa

DNGR-1 (CLEC9A) is a receptor for necrotic cells required by DCs to cross-prime CTLs against dead cell antigens in mice. It is currently unknown how DNGR-1 couples dead cell recognition to cross-priming. Here we found that DNGR-1 did not mediate DC activation by dead cells but rather diverted necrotic cell cargo into a recycling endosomal compartment, favoring cross-presentation to CD8(+) T cells. DNGR-1 regulated cross-priming in non-infectious settings such as immunization with antigen-bearing dead cells, as well as in highly immunogenic situations such as infection with herpes simplex virus type 1. Together, these results suggest that DNGR-1 is a dedicated receptor for cross-presentation of cell-associated antigens. Our work thus underscores the importance of cross-priming in immunity and indicates that antigenicity and adjuvanticity can be decoded by distinct innate immune receptors. The identification of specialized receptors that regulate antigenicity of virus-infected cells reveals determinants of antiviral immunity that might underlie the human response to infection and vaccination.

Topics: Alphavirus Infections; Animals; Antigen Presentation; Antigens, Surface; CD8-Positive T-Lymphocytes; Cells, Cultured; Cross-Priming; Dendritic Cells; Endocytosis; Fibroblasts; Herpes Simplex; Humans; Lectins, C-Type; Lung; Mice; Mice, Inbred C57BL; Myeloid Cells; Necrosis; Ovalbumin; Protein Transport; Receptors, Immunologic; Recombinant Proteins; Toll-Like Receptor 3

Apoptotic death of T lymphocytes is critical for shutdown of immune responses and hemopoietic cell homeostasis. Both death receptor (Fas) activation and mitochondrial apoptosis triggered by the BH3-only protein Bim have been implicated in the killing of antigen-stimulated T cells. We examined mice lacking the gene encoding Bim (Bcl2l11) and with the inactivating lpr mutation in the gene encoding Fas (Fas), designated Bcl2l11(-/-)Fas(lpr/lpr) mice. Shutdown of an acute T cell response to herpes simplex virus involved only Bim with no contribution by Fas, whereas both pathways synergized in killing antigen-stimulated T cells in chronic infection with murine gamma-herpesvirus. Bcl2l11(-/-)Fas(lpr/lpr) mice developed remarkably enhanced and accelerated fatal lymphadenopathy and autoimmunity compared to mice lacking only one of these apoptosis inducers. These results identify critical overlapping roles for Fas and Bim in T cell death in immune response shutdown and prevention of immunopathology and thereby resolve a long-standing controversy.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Autoimmunity; Bcl-2-Like Protein 11; CD8-Positive T-Lymphocytes; Chronic Disease; fas Receptor; Gammaherpesvirinae; Herpes Simplex; Herpesviridae Infections; Herpesvirus 1, Human; Lymphatic Diseases; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Ovalbumin; Proto-Oncogene Proteins; T-Lymphocyte Subsets

The mechanisms responsible for the immunosuppression associated with sepsis or some chronic blood infections remain poorly understood. Here we show that infection with a malaria parasite (Plasmodium berghei) or simple systemic exposure to bacterial or viral Toll-like receptor ligands inhibited cross-priming. Reduced cross-priming was a consequence of downregulation of cross-presentation by activated dendritic cells due to systemic activation that did not otherwise globally inhibit T cell proliferation. Although activated dendritic cells retained their capacity to present viral antigens via the endogenous major histocompatibility complex class I processing pathway, antiviral responses were greatly impaired in mice exposed to Toll-like receptor ligands. This is consistent with a key function for cross-presentation in antiviral immunity and helps explain the immunosuppressive effects of systemic infection. Moreover, inhibition of cross-presentation was overcome by injection of dendritic cells bearing antigen, which provides a new strategy for generating immunity during immunosuppressive blood infections.

Topics: Animals; Antigen Presentation; Antigens, Viral; CpG Islands; Dendritic Cells; Herpes Simplex; Herpesvirus 1, Human; Immune Tolerance; In Vitro Techniques; Ligands; Malaria; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Transgenic; Ovalbumin; Plasmodium berghei; T-Lymphocytes, Cytotoxic; Toll-Like Receptors

Immunization of the neonate is a highly desirable goal for vaccine developers, since the neonate is profoundly susceptible to a number of viral and bacterial pathogens. The neonatal immune system tends to generate Th2 recall responses, known as neonatal tolerance, which may not protect against viral challenge later in life. In this study we demonstrate that a potent immune proinflammatory stimulator, heat-shock protein 70 (hsp70), can act as an effective and safe adjuvant in neonates. Priming of neonates with hsp70 coupled to a viral MHC Class I-restricted epitope (gB498-505) and injection with recombinant gB generated strong cytotoxic T lymphocyte (CTL) responses and a Th1 primary T helper cell response during the neonatal period. In addition, enhanced CTL and predominant Th1 recall responses to viral antigens were observed following secondary challenge as adults. These responses were sufficient to allow protection against a lethal challenge with Herpes Simplex Virus Type-1 (HSV-1). Therefore, hsp70 in conjunction with viral epitopes and recombinant viral protein can perhaps prime protective immune responses to herpes viruses early in life when infection, which can be life-threatening, and the establishment of latency frequently occur.

Topics: Adjuvants, Immunologic; Animals; Animals, Newborn; Chlorocebus aethiops; Egg Proteins; Herpes Simplex; Herpes Simplex Virus Vaccines; HSP70 Heat-Shock Proteins; Mice; Mice, Inbred C57BL; Ovalbumin; Peptide Fragments; Simplexvirus; Vaccines, Synthetic; Vero Cells

The CC chemokine receptor (CCR) 7 ligands CCL21 and CCL19 were recently described as essential elements for establishing the microenvironment needed to initiate optimal immune responses in secondary lymphoid tissues. In the present study we have kinetically investigated the primary responses of naive DO11.10 TCR-transgenic CD4+ T cells (OVA323-339 peptide specific) adoptively transferred into normal BALB/c mice given plasmid DNA encoding CCR7 ligands. The primary responses of CD4+ Tg-T cells in CCR7 ligand DNA recipients occurred more promptly, reaching levels higher than those observed in vector controls. In line with enhanced specific immunity, the T-cell population in CCR7 ligand recipients underwent more in vivo cell division following Ag stimulation, and a higher percentage of Ag-specific T cells expressed an activation phenotype. Moreover, the enhanced primary responses of naive CD4+ T cells appeared to act via affects on migration and maturation of CD11c+ dendritic cells in the draining lymph nodes. In addition following mucosal challenge of herpes simplex virus-immune mice with virus, those that had received CCL21 or CCL19 during priming contained a higher frequency of responding CD4 T cells in lymph nodes and the site of infection. Moreover, CCL21- and CCL19-treated mice showed less severe disease and better survival following challenge. Our results are discussed in terms of the relevance of CCR7 ligand preimmunization to improve vaccine.

Topics: Adoptive Transfer; Animals; CD4-Positive T-Lymphocytes; Cell Division; Chemokine CCL19; Chemokine CCL21; Chemokines, CC; Dendritic Cells; Female; Herpes Simplex; Immunologic Memory; Ligands; Mice; Mice, Inbred BALB C; Ovalbumin; Peptide Fragments; Receptors, CCR7; Receptors, Chemokine; Simplexvirus; Vaccines, DNA; Vagina

Recent observations have indicated that viral persistence and tumor spreading could occur because of effector function-defective CD8(+) T cells. Although chronic exposure to Ag, lack of CD4 help, and epitope dominance are suggested to interfere with CTL differentiation, mechanisms underlying the defective effector function remain obscure. We demonstrate in this report that lymphotoxin alpha-deficient mice develop CD8(+) T cells at normal frequencies when infected with HSV or immunized with OVA Ag but show impaired cytotoxic and cytokine-mediated effector functions resulting in enhanced susceptibility to HSV-induced encephalitis. Although these cells display near normal levels of perforin and Fas ligand, they remain largely at a naive state as judged by high expression of CD62 ligand and failure to up-regulate activation or memory markers. In particular, these CD8(+) T cells revealed inadequate expression of the IL-12 receptor, thus establishing a link between CTL differentiation and LTalpha possibly through regulation of IL-12 receptor. Viruses and tumors could evade immunity by targeting the same pathway.

Topics: Amino Acid Sequence; Animals; Biomarkers; CD8-Positive T-Lymphocytes; Cells, Cultured; Cytotoxicity, Immunologic; Encephalitis, Viral; Epitopes, T-Lymphocyte; Female; Genetic Predisposition to Disease; Herpes Simplex; Herpesvirus 1, Human; Immunophenotyping; Lymphocyte Activation; Lymphotoxin-alpha; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, SCID; Molecular Sequence Data; Ovalbumin; Spleen; T-Lymphocytes, Cytotoxic

In the etiology of Behçet's disease (BD), viral infection has long been postulated as a contributing factor, and viral involvement has been demonstrated. However, viral infection alone is not sufficient to explain the pathogenesis of BD, and some evidence suggests that immunologic abnormalities are also important. To study the possible role of immune regulation in the development of BD-like symptoms induced by herpes simplex virus inoculation in ICR mice, macrophages were deleted by use of liposome-encapsulated clodronate (lip-Cl(2)MDP). Treatment with lip-Cl(2)MDP suppressed the development of BD-like symptoms, and this suppression was correlated with the induction of interleukin-4 expression in mouse spleens. When the Th2 adjuvant ovalbumin (OVA)-alum was injected into mice with BD-like symptoms, their cutaneous symptoms improved. Adoptive transfer with splenocytes from OVA-alum-injected mice also resulted in improvement. These findings suggest that up-regulated Th2 cytokine expression can attenuate the development of and improve some BD-like symptoms.

Topics: Animals; Behcet Syndrome; Clodronic Acid; Disease Models, Animal; Drug Carriers; Herpes Simplex; Herpesvirus 1, Human; Humans; Interleukin-4; Liposomes; Macrophages; Male; Mice; Mice, Inbred ICR; Ovalbumin; Spleen; Th2 Cells