RESUMEN
The ability of different CD4+ T cell subsets to help CD8+ T-cell response is not fully understood. Here, we found using the murine system that Th17 cells induced by IL-1ß, unlike Th1, were not effective helpers for antiviral CD8 responses as measured by IFNγ-producing cells or protection against virus infection. However, they skewed CD8 responses to a Tc17 phenotype. Thus, the apparent lack of help was actually immune deviation. This skewing depended on both IL-21 and IL-23. To overcome this effect, we inhibited Th17 induction by blocking TGF-ß. Anti-TGF-ß allowed the IL-1ß adjuvant to enhance CD8+ T-cell responses without skewing the phenotype to Tc17, thereby providing an approach to harness the benefit of common IL-1-inducing adjuvants like alum without immune deviation.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Inmunidad Celular/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Anticuerpos Bloqueadores/inmunología , Anticuerpos Bloqueadores/farmacología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/metabolismo , Epítopos de Linfocito T/inmunología , Citometría de Flujo , Interferón gamma/inmunología , Interferón gamma/metabolismo , Interleucina-1beta/inmunología , Interleucina-1beta/metabolismo , Interleucina-1beta/farmacología , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Linfocitos T Colaboradores-Inductores/metabolismo , Células TH1/inmunología , Células TH1/metabolismo , Células Th17/efectos de los fármacos , Células Th17/inmunología , Células Th17/metabolismo , Factor de Crecimiento Transformador beta/inmunología , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
cAMP signalling is both a major pathway as well as a key therapeutic target for inducing immune tolerance and is involved in Treg cell (regulatory T-cell) function. To achieve potent immunoregulation, cAMP can act through several downstream effectors. One proposed mechanism is that cAMP-mediated suppression, including immunosuppression by Treg cells, results from activation of PKA (protein kinase A) leading to the induction of the transcription factor ICER (inducible cAMP early repressor). In the present study, we examined CD4(+)CD25(-) Teff cell (effector T-cell) and CD4(+)CD25(+) Treg cell immune responses in Crem (cAMP-response-element modulator) gene-deficient mice which lack ICER (Crem(-/-)/ICER-deficient mice). ICER deficiency did not significantly alter the frequency or number of Treg cells and Teff cells. Treg cells or a pharmacological increase in cAMP suppressed Teff cells from Crem(+/+) and Crem(-/-)/ICER-deficient mice to an equivalent degree, demonstrating that ICER is dispensable in these functions. Additionally, activating the cAMP effector Epac (exchange protein directly activated by cAMP) suppressed Teff cells. Treg cells expressed low levels of all cyclic nucleotide Pde (phosphodiesterase) genes tested, but high levels of Epac. These data identify ICER as a redundant mediator of Treg cells and cAMP action on Teff cells and suggest that Epac may function as an alternative effector to promote cAMP-dependent Teff cell suppression.
Asunto(s)
Modulador del Elemento de Respuesta al AMP Cíclico/inmunología , Proteínas Quinasas Dependientes de AMP Cíclico/inmunología , AMP Cíclico/inmunología , Factores de Intercambio de Guanina Nucleótido/inmunología , Tolerancia Inmunológica/fisiología , Linfocitos T Reguladores/inmunología , Animales , Proliferación Celular/fisiología , AMP Cíclico/genética , Modulador del Elemento de Respuesta al AMP Cíclico/genética , Proteínas Quinasas Dependientes de AMP Cíclico/genética , Femenino , Factores de Intercambio de Guanina Nucleótido/genética , Ratones , Ratones Noqueados , Linfocitos T Reguladores/citologíaRESUMEN
Antigen-driven expansion of specific CD4 T cells diminishes, on a per cell basis, as infused cell number increases. There is a linear relation between log precursor number and log factor of expansion (FE), with a slope of â¼-0.5 over a range from 3 to 30,000 precursors. Cell number dependence of FE is observed at low precursor number, implying that the underlying process physiologically regulates antigen-driven T-cell expansion. FE of small numbers of transgenic precursors is not significantly affected by concomitant responses of large numbers of cells specific for different antigens. Increasing antigen amount or exogenous IL-2, IL-7, or IL-15 does not significantly affect FE, nor does FE depend on Fas, TNF-α receptor, cytotoxic T-lymphocyte antigen-4, IL-2, or IFN-γ. Small numbers of Foxp3-deficient T-cell receptor transgenic cells expand to a greater extent than do large numbers, implying that this effect is not mediated by regulatory T cells. Increasing dendritic cell number does result in larger FE, but the quantitative relation between FE and precursor number is not abrogated. Although not excluding competition for peptide/MHC complexes as an explanation, fall in FE with increasing precursor number could be explained by a negative feedback in which increasing numbers of responding cells in a cluster inhibit the expansion of cells of the same specificity within that cluster.
Asunto(s)
Antígenos , Linfocitos T CD4-Positivos/citología , Proliferación Celular , Animales , Citocinas/farmacología , Células Dendríticas/citología , Retroalimentación Fisiológica , Activación de Linfocitos , Recuento de Linfocitos , RatonesRESUMEN
Vaccine-induced T-helper 17 (Th17) cells are necessary and sufficient to protect against fungal infection. Although live fungal vaccines are efficient in driving protective Th17 responses and immunity, attenuated fungi may not be safe for human use. Heat-inactivated formulations and subunit vaccines are safer but less potent and require adjuvant to increase their efficacy. Here, we show that interleukin 1 (IL-1) enhances the capacity of weak vaccines to induce protection against lethal Blastomyces dermatitidis infection in mice and is far more effective than lipopolysaccharide. While IL-1 enhanced expansion and differentiation of fungus-specific T cells by direct action on those cells, cooperation with non-T cells expressing IL-1R1 was necessary to maximize protection. Mechanistically, IL-17 receptor signaling was required for the enhanced protection induced by IL-1. Thus, IL-1 enhances the efficacy of safe but inefficient vaccines against systemic fungal infection in part by increasing the expansion of CD4(+) T cells, allowing their entry into the lungs, and inducing their differentiation to protective Th17 cells.
Asunto(s)
Adyuvantes Inmunológicos/administración & dosificación , Blastomyces/inmunología , Vacunas Fúngicas/inmunología , Interleucina-1/administración & dosificación , Células Th17/inmunología , Animales , Blastomicosis/inmunología , Blastomicosis/mortalidad , Blastomicosis/prevención & control , Linfocitos T CD4-Positivos/inmunología , Diferenciación Celular , Movimiento Celular , Proliferación Celular , Modelos Animales de Enfermedad , Femenino , Vacunas Fúngicas/administración & dosificación , Pulmón/inmunología , Ratones , Ratones Endogámicos C57BL , Análisis de SupervivenciaRESUMEN
The transmembrane helical bundle of G protein-coupled receptors (GPCRs) dimerize through helix-helix interactions in response to inflammatory stimulation. A strategy was developed to target the helical dimerization site of GPCRs by peptidomimetics with drug like properties. The concept was demonstrated by selecting a potent backbone cyclic helix mimetic from a library that derived from the dimerization region of chemokine (C-C motif) receptor 2 (CCR2) that is a key player in Multiple Sclerosis. We showed that CCR2 based backbone cyclic peptide having a stable helix structure inhibits specific CCR2-mediated chemotactic migration.
Asunto(s)
Quimiotaxis/efectos de los fármacos , Peptidomiméticos/química , Peptidomiméticos/farmacología , Multimerización de Proteína/efectos de los fármacos , Receptores CCR2/química , Receptores CCR2/metabolismo , Línea Celular , Humanos , Monocitos/citología , Monocitos/efectos de los fármacos , Monocitos/metabolismo , Péptidos Cíclicos/química , Péptidos Cíclicos/farmacología , Estructura Secundaria de Proteína , Urea/química , Urea/farmacologíaRESUMEN
IL-1 causes a marked increase in the degree of expansion of naïve and memory CD4 T cells in response to challenge with their cognate antigen. The response occurs when only specific CD4 T cells can respond to IL-1beta, is not induced by a series of other cytokines and does not depend on IL-6 or CD-28. When WT cells are primed in IL-1R1(-/-) recipients, IL-1 increases the proportion of cytokine-producing transgenic CD4 T cells, especially IL-17- and IL-4-producing cells, strikingly increases serum IgE levels and serum IgG1 levels. IL-1beta enhances antigen-mediated expansion of in vitro primed Th1, Th2, and Th17 cells transferred to IL-1R1(-/-) recipients. The IL-1 receptor antagonist diminished responses to antigen plus lipopolysaccharide (LPS) by approximately 55%. These results indicate that IL-1beta signaling in T cells markedly induces robust and durable primary and secondary CD4 responses.
Asunto(s)
Antígenos/inmunología , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/inmunología , Diferenciación Celular/inmunología , Interleucina-1/inmunología , Animales , Antígenos CD28/inmunología , Proliferación Celular , Femenino , Inmunoglobulinas/inmunología , Memoria Inmunológica/inmunología , Interleucina-17/inmunología , Interleucina-6/inmunología , Ratones , Ratones Noqueados , Receptores Tipo I de Interleucina-1/deficiencia , Receptores Tipo I de Interleucina-1/genética , Receptores Tipo I de Interleucina-1/inmunología , Receptores Tipo I de Interleucina-1/metabolismoRESUMEN
Here, we show that interleukin-1 (IL-1) enhances antigen-driven CD8 T cell responses. When administered to recipients of OT-I T cell receptor transgenic CD8 T cells specific for an ovalbumin (OVA) peptide, IL-1 results in an increase in the numbers of wild-type but not IL1R1(-/-) OT-I cells, particularly in spleen, liver, and lung, upon immunization with OVA and lipopolysaccharide. IL-1 administration also results in an enhancement in the frequency of antigen-specific cells that are granzyme B(+), have cytotoxic activity, and/ or produce interferon γ (IFN-γ). Cells primed in the presence of IL-1 display enhanced expression of granzyme B and increased capacity to produce IFN-γ when rechallenged 2 mo after priming. In three in vivo models, IL-1 enhances the protective value of weak immunogens. Thus, IL-1 has a marked enhancing effect on antigen-specific CD8 T cell expansion, differentiation, migration to the periphery, and memory.
Asunto(s)
Linfocitos T CD8-positivos/efectos de los fármacos , Memoria Inmunológica/efectos de los fármacos , Interleucina-1/farmacología , Animales , Linfocitos T CD8-positivos/inmunología , Femenino , Inmunización , Interferón gamma/biosíntesis , Listeria monocytogenes/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BLRESUMEN
BACKGROUND: Abolishing the inhibitory signal of intracellular cAMP by phosphodiesterases (PDEs) is a prerequisite for effector T (Teff) cell function. While PDE4 plays a prominent role, its control of cAMP levels in Teff cells is not exclusive. T cell activation has been shown to induce PDE8, a PDE isoform with 40- to 100-fold greater affinity for cAMP than PDE4. Thus, we postulated that PDE8 is an important regulator of Teff cell functions. METHODOLOGY/PRINCIPAL FINDINGS: We found that Teff cells express PDE8 in vivo. Inhibition of PDE8 by the PDE inhibitor dipyridamole (DP) activates cAMP signaling and suppresses two major integrins involved in Teff cell adhesion. Accordingly, DP as well as the novel PDE8-selective inhibitor PF-4957325-00 suppress firm attachment of Teff cells to endothelial cells. Analysis of downstream signaling shows that DP suppresses proliferation and cytokine expression of Teff cells from Crem-/- mice lacking the inducible cAMP early repressor (ICER). Importantly, endothelial cells also express PDE8. DP treatment decreases vascular adhesion molecule and chemokine expression, while upregulating the tight junction molecule claudin-5. In vivo, DP reduces CXCL12 gene expression as determined by in situ probing of the mouse microvasculature by cell-selective laser-capture microdissection. CONCLUSION/SIGNIFICANCE: Collectively, our data identify PDE8 as a novel target for suppression of Teff cell functions, including adhesion to endothelial cells.
Asunto(s)
3',5'-AMP Cíclico Fosfodiesterasas/metabolismo , Modulador del Elemento de Respuesta al AMP Cíclico/metabolismo , Linfocitos T/citología , 3',5'-AMP Cíclico Fosfodiesterasas/antagonistas & inhibidores , 3',5'-AMP Cíclico Fosfodiesterasas/genética , Animales , Linfocitos T CD4-Positivos/citología , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/metabolismo , Adhesión Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Quimiocina CXCL12/genética , Claudina-5 , AMP Cíclico/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 4/genética , Citocinas/metabolismo , Dipiridamol/farmacología , Endotelio Vascular/citología , Femenino , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Hidrólisis , Espacio Intracelular/efectos de los fármacos , Espacio Intracelular/metabolismo , Proteínas de la Membrana/metabolismo , Ratones , Inhibidores de Fosfodiesterasa/farmacología , Linfocitos T/efectos de los fármacos , Linfocitos T/metabolismo , Células TH1/efectos de los fármacos , Células TH1/metabolismo , Uniones Estrechas/efectos de los fármacos , Uniones Estrechas/metabolismo , Factores de TiempoRESUMEN
TH1 memory T cells derived from T cell receptor transgenic mice, in which the T cell antigen receptor is specific for a cytochrome C peptide in association with I-E(k), were transferred into normal B10.A mice and allowed to adopt a resting phenotype. When challenged, 30-60 days after transfer, with i.v. cytochrome C, the transgenic cells rapidly became activated, expressed mRNA for IFNgamma, and began to divide. However, after 48 h, the frequency of the cells fell progressively, reaching levels only slightly above the limit of detection by day 8 and thereafter remain depressed for up to 90 days. The remaining cells were anergic as shown by limitation in proliferation and IFNgamma production in response to in vitro antigen stimulation. Even if challenged with antigen emulsified in complete Freund's adjuvant, the overall pattern was similar, except that in the draining lymph nodes, the surviving antigen-specific cells were not anergic, although spleen cells were still strikingly anergic. Thus, antigenic challenge of mice possessing resting memory TH1 CD4 T cells leads to the unanticipated loss of most of the specific cells and an apparent depletion rather than enhancement of immunologic memory.