Project description:The activation of TLR-MyD88 (Toll like receptor- Myeloid differentiation factor 88) signaling within T cells functions as a potent costimulatory signal that boosts antitumor and antiviral responses. However, the molecular mechanisms underlying the costimulatory processes are poorly understood. We compared microarray gene analysis data between TLR1-TLR2 stimulated and unstimulated T cell receptor transgenic âpmelâ and MyD88-/-pmel CD8+ T cells and identified changes in the expression levels of several TNF family members. In particular, TLR-stimulation increased 4-1BB levels in pmel but not in MyD88-/-pmel T cells. A link between 4-1BB and TLR1-TLR2 signaling in CD8+ T cells was highlighted by in fact that 4-1BB-/- T cells exhibited suboptimal responses to TLR1-TLR2 agonist, but responded normally to CD28 or OX40 costimulation. Moreover, blocking 4-1BB signaling with antibodies also hindered the costimulatory effects of the TLR1-TLR2 agonist. The elevated levels of 4-1BB transcripts in TLR1-TLR2âstimulated cells were not due to increased mRNA stability nor increased histone activation but instead were associated with increased binding of p65 and c-Jun to two distinct 4-1BB promoter sites. Combining TLR1-TLR2 ligand with an agonistic anti-4-1BB antibody enhanced the antitumor activity in mice with established melanoma tumors. These studies reveal that the costimulatory effects of TLR1-TLR2 signaling in CD8+ T cells are in part mediated by 4-1BB and are important for mounting an effective antitumor immune response. CD8+ T cells from the B6.Cg-Thy1/Cy Tg(TcraTcrb)8Rest/J mice, referred to as âpmelâ T cells or from MyD88 knockout pmel mice (MyD88â/âpmel) were sorted. pmel and MyD88â/âpmel T cells were activated using MyD88â/â CD8 T cell-depleted splenocytes pulsed with 10ng/ml of mgp100. This was with or without 10µg/ml of Pam3CSK4. pmel or MyD88â/âpmel CD8 T cells were enriched and used for the extraction of RNA used for genomic analysis.
Project description:The activation of TLR-MyD88 (Toll like receptor- Myeloid differentiation factor 88) signaling within T cells functions as a potent costimulatory signal that boosts antitumor and antiviral responses. However, the molecular mechanisms underlying the costimulatory processes are poorly understood. We compared microarray gene analysis data between TLR1-TLR2 stimulated and unstimulated T cell receptor transgenic ‘pmel’ and MyD88-/-pmel CD8+ T cells and identified changes in the expression levels of several TNF family members. In particular, TLR-stimulation increased 4-1BB levels in pmel but not in MyD88-/-pmel T cells. A link between 4-1BB and TLR1-TLR2 signaling in CD8+ T cells was highlighted by in fact that 4-1BB-/- T cells exhibited suboptimal responses to TLR1-TLR2 agonist, but responded normally to CD28 or OX40 costimulation. Moreover, blocking 4-1BB signaling with antibodies also hindered the costimulatory effects of the TLR1-TLR2 agonist. The elevated levels of 4-1BB transcripts in TLR1-TLR2–stimulated cells were not due to increased mRNA stability nor increased histone activation but instead were associated with increased binding of p65 and c-Jun to two distinct 4-1BB promoter sites. Combining TLR1-TLR2 ligand with an agonistic anti-4-1BB antibody enhanced the antitumor activity in mice with established melanoma tumors. These studies reveal that the costimulatory effects of TLR1-TLR2 signaling in CD8+ T cells are in part mediated by 4-1BB and are important for mounting an effective antitumor immune response.
Project description:Human T cells isolated from healthy donors were transduced with non-tonically signaling CARs or tonically signaling CARs, each with CD28z or 4-1BB costimulatory domains Human T cells isolated from healthy donors were transduced with non-tonically signaling CARs or tonically signaling CARs, each with CD28z or 4-1BB costimulatory domains
Project description:CD4+ T cells recognize antigens through their T cell receptors (TCRs); however, additional signals involving costimulatory receptors, for example, CD28, are required for proper T cell activation. Alternative costimulatory receptors have been proposed, including members of the Toll-like receptor (TLR) family, such as TLR5 and TLR2. To understand the molecular mechanism underlying a potential costimulatory role for TLR5, we generated detailed molecular maps and logical models for the TCR and TLR5 signaling pathways and a merged model for cross-interactions between the two pathways. Furthermore, we validated the resulting model by analyzing how T cells responded to the activation of these pathways alone or in combination, in terms of the activation of the transcriptional regulators CREB, AP-1 (c-Jun), and NF-κB (p65). Our merged model accurately predicted the experimental results, showing that the activation of TLR5 can play a similar role to that of CD28 activation with respect to AP-1, CREB, and NF-κB activation, thereby providing insights regarding the cross-regulation of these pathways in CD4+ T cells.
Project description:CD4+ T cells recognize antigens through their T cell receptors (TCRs); however, additional signals involving costimulatory receptors, for example, CD28, are required for proper T cell activation. Alternative costimulatory receptors have been proposed, including members of the Toll-like receptor (TLR) family, such as TLR5 and TLR2. To understand the molecular mechanism underlying a potential costimulatory role for TLR5, we generated detailed molecular maps and logical models for the TCR and TLR5 signaling pathways and a merged model for cross-interactions between the two pathways. Furthermore, we validated the resulting model by analyzing how T cells responded to the activation of these pathways alone or in combination, in terms of the activation of the transcriptional regulators CREB, AP-1 (c-Jun), and NF-κB (p65). Our merged model accurately predicted the experimental results, showing that the activation of TLR5 can play a similar role to that of CD28 activation with respect to AP-1, CREB, and NF-κB activation, thereby providing insights regarding the cross-regulation of these pathways in CD4+ T cells.
Project description:We generated a new B7-H3 CAR-T cell costimulatory domain using TMIGD2 and found it was as good or better than the CD28.4-1BB costimulatory domain. Little is known about TMIGD2 signaling, so we examined how each CAR signals individually compared to CD19.CD28.4-1BB control CAR-T cells.
Project description:mRNA vaccines have demonstrated efficacy against COVID-19. However, concerns regarding waning immunity and breakthrough infections have motivated the development of next-generation vaccines with enhanced efficacy. In this study, we investigated the impact of 4-1BB costimulation on immune responses elicited by mRNA vaccines in mice. We first vaccinated mice with an mRNA vaccine encoding the SARS-CoV-2 spike antigen like the Moderna and Pfizer-BioNTech vaccines, followed by administration of 4-1BB costimulatory antibodies at various times post-vaccination. Administering 4-1BB costimulatory antibodies during the priming phase did not enhance immune responses. However, administering 4-1BB costimulatory antibodies after 96 hours elicited a significant improvement in CD8 T cell responses, leading to enhanced protection against breakthrough infections. A similar improvement in immune responses was observed with multiple mRNA vaccines, including vaccines against common cold coronavirus, human immunodeficiency virus (HIV), and arenavirus. These findings demonstrate a time-dependent effect by 4-1BB costimulation and provide insights for developing improved mRNA vaccines.
Project description:Chimeric antigen receptors (CARs) are synthetic proteins that redirect T cell specificity by linking an extracellular ligand binding domain to intracellular T cell signaling domains. CAR-expressing T (CAR-T) cells have demonstrated significant efficacy for the treatment of refractory B cell malignancies and are being evaluated as immunotherapeutic reagents for many other cancers. CAR designs are based on the fundamental principles of TCR recognition and most CARs employ the T cell-activating CD3z endodomain alongside a costimulatory domain from CD28 or 4-1BB. However, emerging data suggest that CD28/CD3z and 4-1BB/CD3z signaling modules promote divergent metabolic pathways, gene expression programs, and cell fates. To determine how CAR phosphoprotein signaling drives these disparate cell fates, we analyzed CAR ligation-induced signaling networks in primary human T cells using shotgun mass spectrometry. We isolated CD8+CD62L+ T cells from healthy donors and introduced a CD28/CD3z or 4-1BB/CD3z CAR by lentiviral transduction. Transduced T cells were purified by FACS and expanded once in vitro. When the cells returned to a resting state, CD28/CD3z or 4-1BB/CD3z CAR-T cells were stimulated for 10 or 45 minutes with magnetic microbeads coated with a monoclonal antibody specific for a 9 amino acid tag in the CAR extracellular sequence. CAR-T cells were also left unstimulated for 10 or 45 minutes to serve as controls. Altogether, 8 unique conditions were tested in an experiment and three independent experiments were performed.
Project description:Human T cells isolated from healthy donors were transduced with non-tonically signaling CARs or tonically signaling CARs, each with CD28z or 4-1BB costimulatory domains
Project description:Innate immune signaling protects against pathogens, controls hematopoietic development and functions in oncogenesis, yet the relationship between these mechanisms is incompletely defined. Downregulating the GATA2 transcription factor in fetal hematopoietic progenitor cells upregulates genes encoding innate immune regulators, increases Interferon-g (IFNg) signaling and disrupts differentiation. Here, we demonstrate that deletion of an enhancer that confers GATA2 expression in fetal progenitor cells elevated Toll-Like Receptor (TLR) TLR1/2 and TLR2/6 expression and signaling. Genetic rescue by expressing GATA2 downregulated the elevated TLR signaling. IFNg amplified TLR1/2 and TLR2/6 signaling in GATA2-deficient progenitor cells, synergistically activating cytokine/chemokine genes and elevating cytokine/chemokine production in their myeloid cell progeny. Genome-wide analysis of how IFNg and TLR signaling remodels the progenitor cell transcriptome in GATA2-deficient cells revealed exaggerated responses at innate immune genes harboring motifs for signal-dependent transcription factors. Thus, GATA2 establishes a transcriptome that constrains innate immune signaling, and insufficient GATA2 renders fetal progenitor cells hypersensitive to innate immune signaling.