Project description:Innate and adaptive immune cells can acquire “memory” of encounters with a diverse range of activating signals to tune their response to secondary stimuli. Group 1 innate lymphoid cells (ILC1) are recently discovered tissue-resident sentinels that are essential for early host protection from intracellular pathogens at initial sites of infection. However, whether ILC1 function as short-lived effectors or persist and refine their responsiveness following pathogen challenge is not well understood. Furthermore, whether pathogen-derived antigens directly modulate tissue-resident ILC responses remains unclear. Here, we found that liver-resident ILC1 expand locally and persist following the resolution of mouse cytomegalovirus (MCMV) infection. MCMVexperienced ILC1 acquired stable transcriptional, epigenetic, and phenotypic changes, with an enhanced protective effector response to secondary MCMV challenge. Protective memory ILC1 responses were dependent on the MCMV-encoded glycoprotein m12, but not formed during bystander cytokine activation following heterologous infection. Thus, liver ILC1 acquire adaptive features in a MCMV-specific manner.
Project description:Immunization with radiation-attenuated sporozoites (RAS) can confer sterilizing protection against malaria, although the mechanisms behind this protection are incompletely understood. We performed a systems biology analysis of samples from the Immunization by Mosquito with Radiation Attenuated Sporozoites IMRAS) trial, which comprised P. falciparum RAS-immunized (PfRAS), malaria-naive participants whose protection from malaria infection was subsequently assessed by controlled human malaria infection (CHMI). Blood samples collected after initial PfRAS immunization were analyzed to compare immune responses between protected and non-protected volunteers leveraging integrative analysis of whole blood RNA-seq, high parameter flow cytometry, and single cell CITE-seq of PBMCs.
Project description:We show that tissue-resident ILC1 serve a non-redundant early role in host immunity through rapid production of interferon (IFN)-γ following mouse cytomegalovirus (MCMV) infection.
Project description:We show that tissue-resident ILC1 serve a non-redundant early role in host immunity through rapid production of interferon (IFN)-γ following mouse cytomegalovirus (MCMV) infection.
Project description:This ordinary differential equation model is described in the following article:
"Autocrine and paracrine interferon signalling as ‘ring vaccination’ and ‘contact tracing’ strategies to suppress virus infection in a host"
G. Michael Lavigne, Hayley Russell, Barbara Sherry and Ruian Ke
DOI: 10.1098/rspb.2020.3002
Comment:
This model is based on the ordinary differential equations of the non-spatial model of well-mixed viral infection stated in the manuscript (Eq. 2.1 in the article).
Abstract:
The innate immune response, particularly the interferon response, represents a first line of defence against viral infections. The interferon molecules produced from infected cells act through autocrine and paracrine signalling to turn host cells into an antiviral state. Although the molecular mechanisms of IFN signalling have been well characterized, how the interferon response collectively contribute to the regulation of host cells to stop or suppress viral infection during early infection remain unclear. Here, we use mathematical models to delineate the roles of the autocrine and the paracrine signalling, and show that their impacts on viral spread are dependent on how infection proceeds. In particular, we found that when infection is well-mixed, the paracrine signalling is not as effective; by contrast, when infection spreads in a spatial manner, a likely scenario during initial infection in tissue, the paracrine signalling can impede the spread of infection by decreasing the number of susceptible cells close to the site of infection. Furthermore, we argue that the interferon response can be seen as a parallel to population-level epidemic prevention strategies such as ‘contact tracing’ or ‘ring vaccination’. Thus, our results here may have implications for the outbreak control at the population scale more broadly.
Project description:We present transcriptomic analysis of an infection by a cluster A4 mycobacteriophage of its host, Mycobacterium smegmatis, at six time points (n = 2). Viral transcription is detectable 5 minutes into infection, and viral mRNA makes up the vast majority of all transcription by 30 minutes. Kampy, like many phages, has a genome organized into two arms bearing early- and late-phase genes. We identify two transcriptional start sites (TSS’s) consistent with an early promoter driving expression of half of the genome, along with a second, late-stage promoter that becomes active around 30 minutes after the start of infection.
Project description:Latency-associated nuclear antigen (LANA), a multifunctional protein expressed by the Kaposi sarcoma-associated herpesvirus (KSHV) in latently-infected cells, is required for stable maintenance of the viral episome. This is mediated by two interactions: LANA binds to specific sequences (LBS1 and 2) on viral DNA, and also engages host histones, tethering the viral genome to host chromosomes in mitosis. LANA has also been suggested to affect host gene expression, but both the mechanism(s) and role of this dysregulation in KSHV biology remain unclear. Here we have examined LANA interactions with host chromatin on a genome-wide scale using ChIP-seq, and show that LANA predominantly targets human genes near their transcriptional start sites (TSSs). These host LANA-binding sites are generally found within transcriptionally active promoters and display striking overrepresentation of a consensus DNA sequence virtually identical to the LBS1 motif in KSHV DNA. Comparison of the ChIP-seq profile with whole transcriptome (RNA-seq) data reveals that few of the genes that are differentially regulated in latent infection are occupied by LANA at their promoters. This suggests that direct LANA binding to promoters is not the prime determinant of altered host transcription in KSHV-infected cells. Most surprisingly, the association of LANA to both host and viral DNA is strongly disrupted during the lytic cycle of KSHV. This disruption can be prevented by the inhibition of viral DNA synthesis, suggesting the existence of novel and potent regulatory mechanisms linked to either viral DNA replication or late gene expression. Profiling of KSHV LANA positioning on the host genome and examination of gene expression from promoters bound by KSHV LANA.
Project description:Upon viral infection, NK cells expressing certain germline-encoded receptors are selected, expanded and maintained in an adaptive-like manner. Currently, these are thought to differentiate along a common pathway. However, by fate mapping of single NK cells upon murine cytomegalovirus (MCMV) infection, we identified two distinct NK cell lineages that contributed to adaptive-like responses. One was equivalent to conventional NK (cNK) cells while the other was transcriptionally similar to type 1 innate lymphoid cells (ILC1s). ILC1-like NK cells showed splenic-residency and strong cytokine production but also recognized and killed MCMV-infected cells, guided by activating receptor Ly49H. Moreover, they induced clustering of conventional type 1 dendritic cells and facilitated antigen-specific T cell priming early during MCMV infection, which depended on Ly49H and the NK cell-intrinsic expression of transcription factor Batf3. Thereby, ILC1-like NK cells bridge innate and adaptive viral recognition and unite critical features of cNK cells and ILC1s.