RESUMEN
We have previously shown that gammadelta T cells traffic to the CNS during EAE with concurrently increased expression of beta(2)-integrins and production of IFN-gamma and TNF-alpha. To extend these studies, we transferred bioluminescent gammadelta T cells to WT mice and followed their movement through the acute stages of disease. We found that gammadelta T cells rapidly migrated to the site of myelin oligodendrocyte glycoprotein peptide injection and underwent massive expansion. Within 6 days after EAE induction, bioluminescent gammadelta T cells were found in the spinal cord and brain, peaking in number between days 10 and 12 and then rapidly declining by day 15. Reconstitution of gammadelta T cell(-/-) mice with gammadelta T cells derived from beta(2)-integrin-deficient mice (CD11a, -b or -c) demonstrated that gammadelta T-cell trafficking to the CNS during EAE is independent of this family of adhesion molecules. We also examined the role of gammadelta T-cell-produced IFN-gamma and TNF-alpha in EAE and found that production of both cytokines by gammadelta T cells was required for full development of EAE. These results indicate that gammadelta T cells are critical for the development of EAE and suggest a therapeutic target in demyelinating disease.
Asunto(s)
Movimiento Celular/inmunología , Citocinas/metabolismo , Encefalomielitis Autoinmune Experimental/inmunología , Encefalomielitis Autoinmune Experimental/fisiopatología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Subgrupos de Linfocitos T/inmunología , Traslado Adoptivo , Animales , Encéfalo/inmunología , Encéfalo/patología , Antígenos CD11/genética , Antígenos CD18/metabolismo , Movimiento Celular/genética , Citocinas/genética , Citocinas/inmunología , Encefalomielitis Autoinmune Experimental/diagnóstico , Glicoproteínas/administración & dosificación , Glicoproteínas/inmunología , Interferón gamma/genética , Interferón gamma/metabolismo , Ganglios Linfáticos/citología , Ganglios Linfáticos/inmunología , Antígeno-1 Asociado a Función de Linfocito/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Mutantes , Ratones Transgénicos , Glicoproteína Mielina-Oligodendrócito , Fragmentos de Péptidos/administración & dosificación , Fragmentos de Péptidos/inmunología , Médula Espinal/inmunología , Médula Espinal/patología , Subgrupos de Linfocitos T/citología , Subgrupos de Linfocitos T/metabolismo , Subgrupos de Linfocitos T/trasplante , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
gammadelta T cells represent a small subpopulation of T cells expressing a restricted repertoire of T-cell receptors and, unlike alphabeta T cells, function more as cells of the innate immune system. These cells are found in skin and mucosal sites as well as secondary lymphoid tissues and frequently act as first line of defense sentinels. gammadelta T cells have been implicated in the pathogenesis of demyelinating disease, although little was known regarding their trafficking and effector functions. In this Mini-Review, we highlight recent studies demonstrating that gammadelta T cells migrate rapidly to the CNS during experimental autoimmune encephalomyelitis (EAE), the animal model for multiple sclerosis. gammadelta T-cell trafficking to the CNS is independent of beta(2)-integrins and occurs well before onset of clinical signs of disease, peaking early during the acute phase of disease. gammadelta T-cell-mediated production of inflammatory cytokines, including interferon-gamma and tumor necrosis factor-alpha, appears critical for EAE development, suggesting that these cells may set the stage for activation of other subsets of infiltrating effector cells. These data suggest that gammadelta T cells or subsets of gammadelta T cells may represent a new therapeutic target in demeylinating disease.
Asunto(s)
Encefalomielitis Autoinmune Experimental/inmunología , Subgrupos de Linfocitos T/inmunología , Animales , Citocinas/inmunología , Esclerosis Múltiple/inmunologíaRESUMEN
Lysophosphatidylcholine (LPC) is a chemotactic lysolipid produced during inflammation by the hydrolytic action of phospholipase A(2) enzymes. LPC stimulates chemotaxis of T cells in vitro through activation of the G protein-coupled receptor, G2A. This has led to the proposition that G2A contributes to the recruitment of T cells to sites of inflammation and thus promotes chronic inflammatory autoimmune diseases associated with the generation and subsequent tissue infiltration of auto-antigen-specific effector T cells. However, one study suggests that G2A may negatively regulate T cell proliferative responses to antigen receptor engagement and thereby attenuates autoimmunity by reducing the generation of autoreactive T cells. To address the relative contribution of these G2A-mediated effects to the pathophysiology of T cell-mediated autoimmune disease, we examined the impact of G2A inactivation on the onset and severity of murine experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis (MS). Wild type (G2A(+/+)) and G2A-deficient (G2A(-/-)) C57BL/6J mice exhibited a similar incidence and onset of disease following immunization with MOG(35-55) peptide. Disease severity was only moderately reduced in G2A(-/-) mice. Similar numbers of MOG(35-55) specific T cells were generated in secondary lymphoid organs of MOG(35-55)-immunized G2A(+/+) and G2A(-/-) mice. Comparable numbers of T cells were detected in spinal cords of G2A(+/+) and G2A(-/-) mice. We conclude that the proposed anti-proliferative and chemotactic functions of G2A are not manifested in vivo and therefore therapeutic targeting of G2A is unlikely to be beneficial in the treatment of MS.
Asunto(s)
Proteínas de Ciclo Celular/fisiología , Encefalomielitis Autoinmune Experimental/genética , Encefalomielitis Autoinmune Experimental/inmunología , Receptores Acoplados a Proteínas G/fisiología , Animales , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Proteínas de Ciclo Celular/genética , Proliferación Celular/efectos de los fármacos , Encefalomielitis Autoinmune Experimental/inducido químicamente , Citometría de Flujo/métodos , Eliminación de Gen , Glicoproteínas/efectos adversos , Interferón gamma/metabolismo , Ganglios Linfáticos/efectos de los fármacos , Ganglios Linfáticos/inmunología , Ganglios Linfáticos/patología , Activación de Linfocitos/genética , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Glicoproteína Mielina-Oligodendrócito , Fragmentos de Péptidos/efectos adversos , Receptores Acoplados a Proteínas G/deficiencia , Receptores Acoplados a Proteínas G/genética , Bazo/citología , Bazo/inmunología , Bazo/patología , Linfocitos T/inmunología , Factores de TiempoRESUMEN
The expression of beta 2-integrins on gammadelta T cells in naïve mice or those with experimental autoimmune encephalomyelitis (EAE) remains poorly characterized. We compared beta 2-integrin expression and cytokine production between gammadelta and alphabeta T cells over the acute course of EAE. We observed that unlike in alphabeta T cells, beta 2-integrin expression on gammadelta T cells increased significantly from baseline, peaked at Day 10, and remained unchanged in the draining lymph nodes or declined in the spleen and CNS by Day 15. In addition, IFN-gamma- and TNF-alpha-producing gammadelta T cells infiltrated the CNS rapidly and produced significantly more of these cytokines than alphabeta T cells throughout the course of EAE. These results suggest unique roles for beta 2-integrins in the trafficking of gammadelta versus alphabeta T cells during EAE and that gammadelta T cells infiltrate the CNS rapidly, producing cytokines, which modulate acute disease.
Asunto(s)
Antígenos CD18/biosíntesis , Citocinas/biosíntesis , Encefalomielitis Autoinmune Experimental/inmunología , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Subgrupos de Linfocitos T/inmunología , Animales , Antígenos CD18/inmunología , Citocinas/inmunología , Modelos Animales de Enfermedad , Encefalomielitis Autoinmune Experimental/patología , Femenino , Interferón gamma/biosíntesis , Masculino , Ratones , Ratones Endogámicos C57BL , Médula Espinal/inmunología , Bazo/inmunología , Factor de Necrosis Tumoral alfa/biosíntesisRESUMEN
Multiple sclerosis (MS) is an autoimmune disease characterized by central nervous system (CNS) inflammation and leukocyte infiltration, demyelination of neurons, and blood-brain barrier breakdown. The development of experimental autoimmune encephalomyelitis (EAE), the animal model for MS is dependent on a number of components of the immune system including complement and adhesion molecules. Previous studies in our lab have examined the role of C3, the central complement component, and intercellular adhesion molecule-1 (ICAM-1) a key cell adhesion molecule involved in leukocyte trafficking to sites of inflammation including the CNS. In these studies we demonstrated that myelin oligodendrocyte glycoprotein (MOG)-induced EAE is markedly attenuated in both ICAM-1(-/-) and C3(-/-) mice. Given the pivotal role that these proteins play in EAE, we hypothesized that EAE in ICAM-1(-/-) and C3(-/-) double mutant mice would likely fail to develop. Unexpectedly, EAE in ICAM-1(-/-)xC3(-/-) mice was only modestly attenuated compared to wild type mice and significantly worse than C3(-/-) mice. Leukocyte infiltration was commensurate with disease severity between the three groups of mice. Spinal cord T cells from ICAM-1(-/-)xC3(-/-) mice produced the highest levels of IFN-gamma and TNF-alpha, despite reduced disease severity compared to wild type mice. The mechanisms behind the elevated EAE severity in ICAM-1(-/-)xC3(-/-) mice may relate to altered homing of leukocytes or processing of self-antigens in the double mutant background.
Asunto(s)
Complemento C3/deficiencia , Encefalomielitis Autoinmune Experimental/genética , Encefalomielitis Autoinmune Experimental/fisiopatología , Molécula 1 de Adhesión Intercelular/fisiología , Animales , Antígenos CD/metabolismo , Proliferación Celular/efectos de los fármacos , Complemento C3/genética , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Encefalomielitis Autoinmune Experimental/inducido químicamente , Encefalomielitis Autoinmune Experimental/patología , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/genética , Molécula 1 de Adhesión Intercelular/genética , Leucocitos/metabolismo , Ratones , Ratones Noqueados , Proteínas de la Mielina , Glicoproteína Asociada a Mielina/efectos adversos , Glicoproteína Mielina-Oligodendrócito , Índice de Severidad de la Enfermedad , Médula Espinal/patología , Linfocitos T/efectos de los fármacos , Linfocitos T/metabolismoRESUMEN
PURPOSE: Increasing evidence supports a role for complement in the pathogenesis of age-related macular degeneration (AMD). This study evaluated retinal microglia, T-lymphocytes, and complement deposition in a light-induced retinopathy model. The effect of a serotonin (5-hydroxytryptamine, 5-HT(1A)) agonist on these processes was investigated. METHODS: Rats were dark adapted for 24 hours before a 6-hour blue light exposure. Some animals were predosed subcutaneously with AL-8309A. Retinas were evaluated at different times after light exposure. Paraffin sections were stained with antibody for a microglial marker (Iba1), a T-lymphocyte marker (CD3), and complement components C1q, C3, factor B, factor H, and membrane attack complex (MAC). RESULTS: Light exposure resulted in substantial photoreceptor and RPE loss. Robust microglia activation and migration to the outer retina occurred rapidly. Substantial T-lymphocyte recruitment did not occur. Complement alternative pathway was strongly activated, resulting in the deposition of C3, factor B, factor H, and MAC in the area of photic lesions. Dosing with AL-8309A prevented retinal lesions and decreased microglia activation/recruitment and complement deposition in the outer retina. CONCLUSIONS: In blue light exposed retinas, microglia were activated and migrated toward the outer retina, whereas a T-lymphocyte response was minimal. The innate immune system was markedly activated, with substantial complement deposition in the outer retina after light exposure. This complement deposition was prevented by AL-8309A. This model may be useful in the evaluation of complement inhibitors and other neuroprotectants intended for ocular use. AL-8309 is under evaluation in the clinic and may be useful in the treatment of AMD.
Asunto(s)
Proteínas del Sistema Complemento/metabolismo , Luz/efectos adversos , Microglía/metabolismo , Traumatismos Experimentales por Radiación/prevención & control , Retina/efectos de la radiación , Degeneración Retiniana/prevención & control , Agonistas del Receptor de Serotonina 5-HT1/uso terapéutico , Animales , Recuento de Células , Movimiento Celular , Complemento C3/metabolismo , Factor B del Complemento/metabolismo , Factor H de Complemento/metabolismo , Complejo de Ataque a Membrana del Sistema Complemento/metabolismo , Adaptación a la Oscuridad , Inmunohistoquímica , Inyecciones Subcutáneas , Estrés Oxidativo/efectos de la radiación , Traumatismos Experimentales por Radiación/etiología , Traumatismos Experimentales por Radiación/metabolismo , Ratas , Ratas Sprague-Dawley , Degeneración Retiniana/etiología , Degeneración Retiniana/metabolismo , Linfocitos T/inmunologíaRESUMEN
Activation of islet-specific T cells plays a significant role in the development of type 1 diabetes. In an effort to control T cell activation, we expressed the inhibitory receptor, Ly-49A, on islet-specific mouse CD4 cells. Ag-mediated activation of Ly-49A T cells was inhibited in vitro when the Ly-49A ligand, H-2D(d), was present on APCs. Ag-driven T cell proliferation, cytokine production, and changes in surface receptor expression were significantly reduced. Inhibition was also evident during secondary antigenic challenge. Addition of exogenous IL-2 did not rescue cells from inhibition, suggesting that Ly-49A engagement does not lead to T cell anergy. Importantly, in an adoptive transfer model, Ly-49A significantly delays the onset of diabetes. Together these results demonstrate that the inhibitory receptor Ly-49A effectively limits Ag-specific CD4 cell responses even in the presence of sustained autoantigen expression in vivo.