Project description:Lung resident memory B cells (BRM cells) are elicited after influenza infections of mice, but connections to other pathogens and hosts have yet to be determined, as has their functional significance. We postulate that BRM cells are core components of lung immunity. To test this, we examined whether lung BRM cells are elicited by the respiratory pathogen pneumococcus, are present in humans, and are important in pneumonia defense. Lungs of mice recovered from pneumococcal infections did not contain organized lymphoid structures, but did have non-circulating memory B cells that expressed distinctive surface markers (including CD69, PD-L2, CD80, and CD73) and were poised to secrete antibodies upon stimulation. Human lungs also contained B cells with a resident memory phenotype. In mice recovered from pneumococcal pneumonia, depletion of PD-L2+ B cells, including lung BRM cells, drastically compromised bacterial clearance. These data define lung BRM cells as a common feature of pathogen-experienced lungs and provide direct evidence of a role for these cells in pulmonary anti-bacterial immunity.
Project description:Lung-resident memory B cells (BRM cells) are elicited after influenza infections of mice, but connections to other pathogens and hosts - as well as their functional significance - have yet to be determined. We postulate that BRM cells are core components of lung immunity. To test this, we examined whether lung BRM cells are elicited by the respiratory pathogen pneumococcus, are present in humans, and are important in pneumonia defense. Lungs of mice that had recovered from pneumococcal infections did not contain organized tertiary lymphoid organs, but did have plasma cells and noncirculating memory B cells. The latter expressed distinctive surface markers (including CD69, PD-L2, CD80, and CD73) and were poised to secrete antibodies upon stimulation. Human lungs also contained B cells with a resident memory phenotype. In mice recovered from pneumococcal pneumonia, depletion of PD-L2+ B cells, including lung BRM cells, diminished bacterial clearance and the level of pneumococcus-reactive antibodies in the lung. These data define lung BRM cells as a common feature of pathogen-experienced lungs and provide direct evidence of a role for these cells in pulmonary antibacterial immunity.
Project description:Congenital cytomegalovirus (cCMV) is the most common intrauterine infection, leading to infant neurodevelopmental disabilities. An improved knowledge of correlates of protection against cCMV is needed to guide prevention strategies. Here, we employed a unique ex vivo model of human CMV (HCMV) infection in decidual tissues of women with and without preconception immunity, recapitulating nonprimary versus primary infection at the authentic maternofetal transmission site. We showed that decidual tissues of women with preconception immunity exhibited intrinsic resistance to HCMV, mounting a rapid activation of tissue resident memory CD8+ and CD4+ T cells upon nonprimary infection. We further revealed the role of HCMV-specific decidual-tissue resident CD8+ T cells in local protection against nonprimary HCMV infection. The findings could inform the development of vaccine against cCMV, and provide insights for further studies of the integrity of immune defense against cCMV and other pathogens in the human maternal-fetal interface.
Project description:Leishmaniasis causes a significant disease burden worldwide. Although Leishmania-infected patients become refractory to reinfection following disease resolution, effective immune protection has not yet been achieved by human vaccines. While circulating Leishmania-specific T cells are known to play a critical role in immunity, the role of memory T cells present in peripheral tissues has not been explored. Here, we identify a population of skin-resident Leishmania-specific memory CD4+ T cells. These cells produce IFNγ, and remain resident in the skin when transplanted by skin graft onto naïve mice. They function to recruit circulating T cells to the skin in a CXCR3 dependent manner, resulting in better control of the parasites. Our findings are the first to demonstrate that CD4+ TRM cells form in response to a parasitic infection, and indicate that optimal protective immunity to Leishmania, and thus the success of a vaccine, may depend on generating both circulating and skin-resident memory T cells. Two conditions were analyzed. For each condition, four mice were used, resulting in eight samples in total.
Project description:Tissue resident memory T (TRM) cells mediate the frontline protection against melanoma lung metastasis. We utilized scRNA-seq to investigate the underlying molecular mechanism of central memory T (TCM) to lung TRM development in the prime-boost vaccinaiton regimen.
Project description:Tissue resident memory T cells (TRM) provide superior protection against infection localised to extra-lymphoid compartments in the body. Here we show that CD103+CD8+ TRM cells develop in skin from killer cell lectin-like receptor (KLR)G1-negative precursors that selectively infiltrate the epithelial layer. In the skin, a combination of chemokine-guided epithelial entry, local interleukin (IL)-15 and transforming growth factor (TGF)-β signalling is required for formation and survival of these long-lived memory cells. Importantly, TRM differentiation results in the gradual acquisition of a unique transcriptional profile that differs from that expressed by memory cells in the circulation and other types of skin-resident intra-epithelial T cells, such as the dendritic epidermal T cells (DETC). We provide a comprehensive molecular and developmental framework for the local differentiation of a distinct type of peripheral memory T cell that contributes to an important first-line of immune defence in barrier tissues such as skin and mucosa. 24 samples were analyzed: 3 replicates of memory gB-T CD8+. CD103+ T cells isolated from the skin of C57/BL6 mice on day 30 p.i. with HSV KOS. 3 replicates of memory P14 CD8+ T cells isolated from gut of mice on day 60 p.i. with LCMV Armstrong. 3 replicates of memory gB-T CD8+ T cells from the lung of mice on day 30 p.i. with influenza WSN. 3 replicates of memory CD62L high CD8+ T cells from the spleen of mice on day 30 p.i. with HSV KOS. 3 replicates of memory CD62L low CD8+ T cells from the spleen of mice of day 30 p.i. with HSV KOS. 3 replicates of γδ-DETC isolated from the skin of C57/BL6 mice on day 30 p.i. with HSV KOS. 3 replicates of αβ-DETC from naive TCRδ-/- mice; and 3 replicates of naive gB-T CD8+ T cells from the spleen of naive gB-T transgenic mice.
Project description:Tissue resident memory (Trm) represent a newly described memory T cell population. We have previously characterized a population of Trm that persists within the brain following acute virus infection. Although capable of providing marked protection against a subsequent local challenge, brain Trm do not undergo recall expansion following dissociation from the tissue. Furthermore, these Trm do not depend on the same survival factors as the circulating memory T cell pool as assessed either in vivo or in vitro. To gain greater insight into this population of cells we compared the gene-expression profiles of Trm isolated from the brain to circulating memory T cells isolated from the spleen following an acute virus infection. Trm displayed altered expression of genes involved in chemotaxis, expressed a distinct set of transcription factors and overexpressed several inhibitory receptors. Cumulatively, these data indicates that Trm are a distinct memory T cell population disconnected from the circulating memory T cell pool and displaying a unique molecular signature which likely results in optimal survival and function within their local environment. 13 samples were analyzed: 5 replicates of memory OT-I CD8+.CD103- T cells isolated from the spleen of mice on day 20 p.i. with VSV-OVA. 5 replicates of memory OT-I CD8+CD103+ T cells isolated from the brain of mice on day 20 p.i. with VSV-OVA; and 3 replicates of memory OT-I.CD8+ CD103- T cells isolated from the brain of mice on day 20 p.i. with VSV-OVA
Project description:Tissue-resident memory T-cells (TRM) mediate optimal protection against respiratory infections. Little is known about human TRM. Here we characterized memory T-cells from human lungs. We identify two distinct memory T-cell populations in lung tissue. Lung TRM are poised for rapid, but restrained responsiveness by constitutive expression of genes encoding effector molecules and inhibitory regulators. Although TRM express little T-bet and Eomesodermin, transcription factor signatures revealed that multiple drivers of effector gene expression are active in TRM, including Notch. We show that Notch is required for maintenance of the CD103+ TRM population in mouse lungs. These findings suggests that the lung tissue environment actively maintains the T-cells that protect it from infectious assault through activating the Notch surface receptor in TRM.
Project description:Leishmaniasis causes a significant disease burden worldwide. Although Leishmania-infected patients become refractory to reinfection following disease resolution, effective immune protection has not yet been achieved by human vaccines. While circulating Leishmania-specific T cells are known to play a critical role in immunity, the role of memory T cells present in peripheral tissues has not been explored. Here, we identify a population of skin-resident Leishmania-specific memory CD4+ T cells. These cells produce IFNγ, and remain resident in the skin when transplanted by skin graft onto naïve mice. They function to recruit circulating T cells to the skin in a CXCR3 dependent manner, resulting in better control of the parasites. Our findings are the first to demonstrate that CD4+ TRM cells form in response to a parasitic infection, and indicate that optimal protective immunity to Leishmania, and thus the success of a vaccine, may depend on generating both circulating and skin-resident memory T cells.