RESUMEN
Resident memory T cells (TRM cells) are an important first-line defense against respiratory pathogens, but the unique contributions of lung TRM cell populations to protective immunity and the factors that govern their localization to different compartments of the lung are not well understood. Here, we show that airway and interstitial TRM cells have distinct effector functions and that CXCR6 controls the partitioning of TRM cells within the lung by recruiting CD8 TRM cells to the airways. The absence of CXCR6 significantly decreases airway CD8 TRM cells due to altered trafficking of CXCR6-/- cells within the lung, and not decreased survival in the airways. CXCL16, the ligand for CXCR6, is localized primarily at the respiratory epithelium, and mice lacking CXCL16 also had decreased CD8 TRM cells in the airways. Finally, blocking CXCL16 inhibited the steady-state maintenance of airway TRM cells. Thus, the CXCR6/CXCL16 signaling axis controls the localization of TRM cells to different compartments of the lung and maintains airway TRM cells.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Memoria Inmunológica , Inmunomodulación , Receptores CXCR6/metabolismo , Mucosa Respiratoria/inmunología , Mucosa Respiratoria/metabolismo , Animales , Expresión Génica , Humanos , Inmunofenotipificación , Ratones , Ratones Noqueados , Unión Proteica , Receptores CXCR6/genética , Especificidad del Receptor de Antígeno de Linfocitos TRESUMEN
Although influenza virus infection remains a concerning disease for public health, the roles of individual cytokines during the immune response to influenza infection are not fully understood. We have identified IL-36γ as a key mediator of immune protection during both high- and low-pathogenesis influenza infection. Il36g mRNA is upregulated in the lung following influenza infection, and mice lacking IL-36γ have greatly increased morbidity and mortality upon infection with either H1N1 or H3N2 influenza. The increased severity of influenza infection in IL-36γ-knockout (KO) mice is associated with increased viral titers, higher levels of proinflammatory cytokines early in infection, and more diffuse pathologic conditions late in the disease course. Interestingly, the increased severity of disease in IL-36γ-KO mice correlates with a rapid loss of alveolar macrophages following infection. We find that the alveolar macrophages from naive IL-36γ-KO mice have higher expression of M2-like surface markers compared with wild-type (WT) mice and show increased apoptosis within 24 h of infection. Finally, transfer of WT alveolar macrophages to IL-36γ-KO mice restores protection against lethal influenza challenge to levels observed in WT mice. Together, these data identify a critical role for IL-36γ in immunity against influenza virus and demonstrate the importance of IL-36γ signaling for alveolar macrophage survival during infection.
Asunto(s)
Subtipo H1N1 del Virus de la Influenza A/fisiología , Subtipo H3N2 del Virus de la Influenza A/fisiología , Gripe Humana/inmunología , Interleucina-1/metabolismo , Pulmón/patología , Macrófagos Alveolares/fisiología , Infecciones por Orthomyxoviridae/inmunología , Traslado Adoptivo , Animales , Supervivencia Celular , Células Cultivadas , Humanos , Interleucina-1/genética , Macrófagos Alveolares/trasplante , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Regulación hacia Arriba , Replicación ViralRESUMEN
Resident memory CD8 T (TRM) cells in the lung parenchyma (LP) and airways provide heterologous protection against influenza virus challenge. However, scant knowledge exists regarding factors necessary to establish and maintain lung CD8 TRM. Here we demonstrate that, in contrast to mechanisms described for other tissues, airway, and LP CD8 TRM establishment requires cognate antigen recognition in the lung. Systemic effector CD8 T cells could be transiently pulled into the lung in response to localized inflammation, however these effector cells failed to establish tissue residency unless antigen was present in the pulmonary environment. The interaction of effector CD8 T cells with cognate antigen in the lung resulted in increased and prolonged expression of the tissue-retention markers CD69 and CD103, and increased expression of the adhesion molecule VLA-1. The inability of localized inflammation alone to establish lung TRM resulted in decreased viral clearance and increased mortality following heterosubtypic influenza challenge, despite equal numbers of circulating memory CD8 T cells. These findings demonstrate that pulmonary antigen encounter is required for the establishment of lung CD8 TRM and may inform future vaccine strategies to generate robust cellular immunity against respiratory pathogens.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Subtipo H1N1 del Virus de la Influenza A/fisiología , Vacunas contra la Influenza/inmunología , Gripe Humana/inmunología , Pulmón/inmunología , Infecciones por Orthomyxoviridae/inmunología , Mucosa Respiratoria/fisiología , Animales , Antígenos/inmunología , Antígenos CD , Antígenos de Diferenciación de Linfocitos T , Células Cultivadas , Humanos , Memoria Inmunológica , Integrina alfa1beta1/metabolismo , Lectinas Tipo C , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Carga ViralRESUMEN
CD8+ tissue-resident memory T cells (TRM cells) reside permanently in nonlymphoid tissues and provide a first line of protection against invading pathogens. However, the precise localization of CD8+ TRM cells in the lung, which physiologically consists of a markedly scant interstitium compared with other mucosa, remains unclear. In this study, we show that lung CD8+ TRM cells localize predominantly in specific niches created at the site of regeneration after tissue injury, whereas peripheral tissue-circulating CD8+ effector memory T cells (TEM cells) are widely but sparsely distributed in unaffected areas. Although CD69 inhibited sphingosine 1-phosphate receptor 1-mediated egress of CD8+ T cells immediately after their recruitment into lung tissues, such inhibition was not required for the retention of cells in the TRM niches. Furthermore, despite rigid segregation of TEM cells from the TRM niche, prime-pull strategy with cognate antigen enabled the conversion from TEM cells to TRM cells by creating de novo TRM niches. Such damage site-specific localization of CD8+ TRM cells may be important for efficient protection against secondary infections by respiratory pathogens.
Asunto(s)
Antígenos CD/inmunología , Antígenos de Diferenciación de Linfocitos T/inmunología , Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica , Virus de la Influenza A/inmunología , Lectinas Tipo C/inmunología , Pulmón/inmunología , Infecciones por Orthomyxoviridae/inmunología , Animales , Antígenos CD/genética , Antígenos de Diferenciación de Linfocitos T/genética , Linfocitos T CD8-positivos/patología , Lectinas Tipo C/genética , Pulmón/patología , Ratones , Ratones Transgénicos , Infecciones por Orthomyxoviridae/genética , Infecciones por Orthomyxoviridae/patologíaRESUMEN
The nature and anatomic location of the protective memory CD8(+) T cell subset induced by intranasal vaccination remain poorly understood. We developed a vaccination model to assess the anatomic location of protective memory CD8(+) T cells and their role in lower airway infections. Memory CD8(+) T cells elicited by local intranasal, but not systemic, vaccination with an engineered non-replicative CD8(+) T cell-targeted antigen confer enhanced protection to a lethal respiratory viral challenge. This protection depends on a distinct CXCR3(LO) resident memory CD8(+) T (Trm) cell population that preferentially localizes to the pulmonary interstitium. Because they are positioned close to the mucosa, where infection occurs, interstitial Trm cells act before inflammation can recruit circulating memory CD8(+) T cells into the lung tissue. This results in a local protective immune response as early as 1 day post-infection. Hence, vaccine strategies that induce lung interstitial Trm cells may confer better protection against respiratory pathogens.
Asunto(s)
Antígenos Virales/inmunología , Linfocitos T CD8-positivos/inmunología , Memoria Inmunológica , Infecciones del Sistema Respiratorio/prevención & control , Vaccinia/prevención & control , Vacunas Virales/administración & dosificación , Administración Intranasal , Secuencia de Aminoácidos , Animales , Antígenos Virales/química , Peso Corporal/efectos de los fármacos , Linfocitos T CD8-positivos/virología , Expresión Génica , Inmunidad Mucosa/efectos de los fármacos , Inmunofenotipificación , Pulmón/efectos de los fármacos , Pulmón/inmunología , Pulmón/virología , Ratones , Ratones Transgénicos , Receptores CXCR3/genética , Receptores CXCR3/inmunología , Infecciones del Sistema Respiratorio/inmunología , Infecciones del Sistema Respiratorio/patología , Infecciones del Sistema Respiratorio/virología , Vacunación , Vaccinia/inmunología , Vaccinia/patología , Vaccinia/virología , Virus Vaccinia/química , Virus Vaccinia/efectos de los fármacos , Virus Vaccinia/crecimiento & desarrollo , Virus Vaccinia/patogenicidad , Carga Viral/efectos de los fármacos , Vacunas Virales/biosíntesisRESUMEN
The current influenza vaccine provides narrow protection against the strains included in the vaccine, and needs to be reformulated every few years in response to the constantly evolving new strains. Novel approaches are directed toward developing vaccines that provide broader protection by targeting B and T cell epitopes that are conserved between different strains of the virus. In this paper, we focus on developing mathematical models to explore the CD8 T cell responses to influenza, how they can be boosted, and the conditions under which they contribute to protection. Our models suggest that the interplay between spatial heterogeneity (with the virus infecting the respiratory tract and the immune response being generated in the secondary lymphoid organs) and T cell differentiation (with proliferation occurring in the lymphoid organs giving rise to a subpopulation of resident T cells in the respiratory tract) is the key to understand the dynamics of protection afforded by the CD8 T cell response to influenza. Our results suggest that the time lag for the generation of resident T cells in the respiratory tract and their rate of decay following infection are the key factors that limit the efficacy of CD8 T cell responses. The models predict that an increase in the level of central memory T cells leads to a gradual decrease in the viral load, and, in contrast, there is a sharper protection threshold for the relationship between the size of the population of resident T cells and protection. The models also suggest that repeated natural influenza infections cause the number of central memory CD8 T cells and the peak number of resident memory CD8 T cells to reach their plateaus, and while the former is maintained, the latter decays with time since the most recent infection.
RESUMEN
T cells have the remarkable ability to recognize antigen with great specificity and in turn mount an appropriate and robust immune response. Critical to this process is the initial T cell antigen recognition and subsequent signal transduction events. This antigen recognition can be modulated at the site of TCR interaction with peptide:major histocompatibility (pMHC) or peptide interaction with the MHC molecule. Both events could have a range of effects on T cell fate. Though responses to antigens that bind sub-optimally to TCR, known as altered peptide ligands (APL), have been studied extensively, the impact of disrupting antigen binding to MHC has been highlighted to a lesser extent and is usually considered to result in complete loss of epitope recognition. Here we present a model of viral evasion from CD8 T cell immuno-surveillance by a lymphocytic choriomeningitis virus (LCMV) escape mutant with an epitope for which TCR affinity for pMHC remains high but where the antigenic peptide binds sub optimally to MHC. Despite high TCR affinity for variant epitope, levels of interferon regulatory factor-4 (IRF4) are not sustained in response to the variant indicating differences in perceived TCR signal strength. The CD8+ T cell response to the variant epitope is characterized by early proliferation and up-regulation of activation markers. Interestingly, this response is not maintained and is characterized by a lack in IL-2 and IFNγ production, increased apoptosis and an abrogated glycolytic response. We show that disrupting the stability of peptide in MHC can effectively disrupt TCR signal strength despite unchanged affinity for TCR and can significantly impact the CD8+ T cell response to a viral escape mutant.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Epítopos de Linfocito T/genética , Epítopos de Linfocito T/inmunología , Virus de la Coriomeningitis Linfocítica/fisiología , Mutación , Receptores de Antígenos de Linfocitos T/metabolismo , Animales , Linfocitos T CD8-positivos/citología , Proliferación Celular , Supervivencia Celular , Regulación de la Expresión Génica , Antígenos de Histocompatibilidad/metabolismo , Interferón gamma/biosíntesis , Interleucina-2/biosíntesis , Subunidad alfa del Receptor de Interleucina-2/metabolismo , Activación de Linfocitos , Virus de la Coriomeningitis Linfocítica/inmunología , Ratones , Ratones Endogámicos C57BL , Monitorización Inmunológica , Transducción de SeñalRESUMEN
CD8 airway resident memory T (TRM) cells are a distinctive TRM population with a high turnover rate and a unique phenotype influenced by their localization within the airways. Their role in mediating protective immunity to respiratory pathogens, although suggested by many studies, has not been directly proven. This study provides definitive evidence that airway CD8 TRM cells are sufficient to mediate protection against respiratory virus challenge. Despite being poorly cytolytic in vivo and failing to expand after encountering Ag, airway CD8 TRM cells rapidly express effector cytokines, with IFN-γ being produced most robustly. Notably, established airway CD8 TRM cells possess the ability to produce IFN-γ faster than systemic effector memory CD8 T cells. Furthermore, naive mice receiving intratracheal transfer of airway CD8 TRM cells lacking the ability to produce IFN-γ were less effective at controlling pathogen load upon heterologous challenge. This direct evidence of airway CD8 TRM cell-mediated protection demonstrates the importance of these cells as a first line of defense for optimal immunity against respiratory pathogens and suggests they should be considered in the development of future cell-mediated vaccines.
Asunto(s)
Antígenos Virales/inmunología , Linfocitos T CD8-positivos/inmunología , Interferón gamma/biosíntesis , Pulmón/inmunología , Infecciones por Orthomyxoviridae/inmunología , Traslado Adoptivo , Animales , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/patología , Linfocitos T CD4-Positivos/virología , Linfocitos T CD8-positivos/citología , Linfocitos T CD8-positivos/trasplante , Tratamiento Basado en Trasplante de Células y Tejidos , Interacciones Huésped-Patógeno , Memoria Inmunológica , Subtipo H1N1 del Virus de la Influenza A/inmunología , Interferón gamma/metabolismo , Pulmón/patología , Pulmón/virología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Infecciones por Orthomyxoviridae/patología , Infecciones por Orthomyxoviridae/terapia , Infecciones por Orthomyxoviridae/virología , Carga Viral , Replicación ViralRESUMEN
Skin has gained substantial attention as a vaccine target organ due to its immunological properties, which include a high density of professional antigen presenting cells (APCs). Previous studies have demonstrated the effectiveness of this vaccination route not only in animal models but also in adults. Young children represent a population group that is at high risk from influenza infection. As a result, this group could benefit significantly from influenza vaccine delivery approaches through the skin and the improved immune response it can induce. In this study, we compared the immune responses in young BALB/c mice upon skin delivery of influenza vaccine with vaccination by the conventional intramuscular route. Young mice that received 5 µg of H1N1 A/Ca/07/09 influenza subunit vaccine using MN demonstrated an improved serum antibody response (IgG1 and IgG2a) when compared to the young IM group, accompanied by higher numbers of influenza-specific antibody secreting cells (ASCs) in the bone marrow. In addition, we observed increased activation of follicular helper T cells and formation of germinal centers in the regional lymph nodes in the MN immunized group, rapid clearance of the virus from their lungs as well as complete survival, compared with partial protection observed in the IM-vaccinated group. Our results support the hypothesis that influenza vaccine delivery through the skin would be beneficial for protecting the high-risk young population from influenza infection.
Asunto(s)
Sistemas de Liberación de Medicamentos/métodos , Vacunas contra la Influenza/administración & dosificación , Vacunas contra la Influenza/inmunología , Infecciones por Orthomyxoviridae/prevención & control , Animales , Anticuerpos Antivirales/sangre , Femenino , Inmunoglobulina G/sangre , Subtipo H1N1 del Virus de la Influenza A/inmunología , Inyecciones Intradérmicas/métodos , Inyecciones Intramusculares , Pulmón/virología , Ratones Endogámicos BALB C , Modelos Animales , Análisis de Supervivencia , Linfocitos T/inmunología , Resultado del Tratamiento , Vacunas de Subunidad/administración & dosificación , Vacunas de Subunidad/inmunología , Carga ViralRESUMEN
Influenza virus is a source of significant health and economic burden from yearly epidemics and sporadic pandemics. Given the potential for the emerging H7N9 influenza virus to cause severe respiratory infections and the lack of exposure to H7 and N9 influenza viruses in the human population, we aimed to quantify the H7N9 cross-reactive memory T cell reservoir in humans and mice previously exposed to common circulating influenza viruses. We identified significant cross-reactive T cell populations in humans and mice; we also found that cross-reactive memory T cells afforded heterosubtypic protection by reducing morbidity and mortality upon lethal H7N9 challenge. In context with our observation that PR8-primed mice have limited humoral cross-reactivity with H7N9, our data suggest protection from H7N9 challenge is indeed mediated by cross-reactive T cell populations established upon previous priming with another influenza virus. Thus, pre-existing cross-reactive memory T cells may limit disease severity in the event of an H7N9 influenza virus pandemic.