CD8+ T-cells inhibit virus replication in SIV-infected rhesus macaques (RM). However, it is unclear to what extent the viral suppression mediated by CD8+ T-cells reflects direct killing of infected cells as opposed to indirect, non-cytolytic mechanisms. In this study, we used functional genomics to investigate potential mechanisms of in vivo viral suppression mediated by CD8+ lymphocytes. Eight chronically SIVmac239-infected RMs underwent CD8+ lymphocyte depletion, and RNA from whole blood was obtained prior to depletion, at the nadir of CD8+ lymphocytes (5 days post-depletion), and during the repopulation phase (11 days post-depletion). Principal components analysis demonstrated that overall gene expression during the nadir of CD8+ T-cells was highly divergent from other intervals. Conversely, the genomic signature of samples from the CD8+ cell rebound phase was similar to that of pre-depletion samples. During CD8+ lymphocyte depletion we detected a strongly significant decrease in the expression of the genes encoding CD8 and CD8 chains, consistent with the near complete CD8+ T-cell depletion measured by flow cytometry. Of note, we observed significant down-regulation of the expression of genes encoding for factors that can suppress SIV replication, including the CCR5-binding chemokine CCL5/Rantes, several retroviral restriction factors (TRIM10, TRIM15, APOBEC3G/H) and defensins. Reduced expression of various genes related to T cell activation and proliferation was also observed. Collectively, these data indicate that depletion of CD8+ lymphocytes in SIV-infected RMs is associated with the establishment of a pattern of gene expression that may result in increased intrinsic permissivity to virus replication.
Transcriptional profiling of experimental CD8(+) lymphocyte depletion in rhesus macaques infected with simian immunodeficiency virus SIVmac239.
No sample metadata fieldsView Samples
Hyperimmune activation is one of the strong predictors of disease progression during pathogenic immunodeficiency virus infections and is mediated in part by sustained type I interferon (IFN) signaling. Combination antiretroviral therapy suppresses hyperimmune activation only partially in HIV-infected individuals. Here, we show that blockade of Programmed Death-1 (PD-1) during chonic SIV infection significantly reduces the expression of transcripts associated with type I IFN signaling in the blood and colorectal tissue of rhesus macaques (RM). The effect of PD-1 blockade on type I IFN signaling was durable and persisted under high viremia, a condition that is seen in nonprogressive SIV infection in their natural hosts. The reduced type I IFN signaling was associated with enhanced expression of some of the junction-associated genes in the colorectal tissue and a profound decrease in LPS levels in plasma suggesting a possible repair of gut associated junctions and decreased microbial translocation. The reduced type I IFN signaling was also associated with enhanced immunity against gut resident pathogenic bacteria, control of gut associated opportunistic infections and survival of SIV-infected RMs. These results reveal novel mechanisms by which PD-1 blockade enhances survival of SIV-infected RMs and have implications for development of novel therapeutic approaches to control HIV/AIDS.
PD-1 blockade during chronic SIV infection reduces hyperimmune activation and microbial translocation in rhesus macaques.
Specimen part, Disease, Disease stage, TreatmentView Samples
In SIV/HIV infection, the gastrointestinal tissue dominates as an important site due to the impact of massive mucosal CD4 depletion and immune activation-induced tissue pathology. Unlike AIDS-susceptible rhesus macaques, natural hosts do not progress to AIDS and resolve immune activation earlier. Here, we examine the role of dendritic cells in mediating immune activation and disease progression. We demonstrate that plasmacytoid dendritic cells (pDC) in the blood upregulate 7-integrin and are rapidly recruited to the colorectum following a pathogenic SIV infection in rhesus macaques. These pDC were capable of producing proinflammatory cytokines and primed a Tc1 response in vitro. Consistent with the upregulation of 7-integrin on pDC, in vivo blockade of 47-integrin dampened pDC recruitment to the colorectum and resulted in reduced immune activation. The upregulation of 7-integrin expression on pDC in the blood was also observed in HIV-infected humans but not in chronically SIV-infected sooty mangabeys that show low levels of immune activation. Our results uncover a new mechanism by which pDC influence immune activation in colorectal tissue following pathogenic immunodeficiency virus infections.
Plasmacytoid dendritic cells are recruited to the colorectum and contribute to immune activation during pathogenic SIV infection in rhesus macaques.
Specimen partView Samples
The 2009 H1N1 influenza pandemic has prompted a significant need for the development of efficient, single-dose, adjuvanted vaccines. Here we investigated the adjuvant potential of CpG oligodeoxynucleotide (ODN) when used with a human seasonal influenza virus vaccine in ferrets. We found that the CpG ODNadjuvanted vaccine effectively increased antibody production and activated type I interferon (IFN) responses compared to vaccine alone. Based on these findings, pegylated IFN- 2b (PEG-IFN) was also evaluated as an adjuvant in comparison to CpG ODN and complete Freunds adjuvant (CFA). Our results showed that all three vaccines with adjuvant added prevented seasonal human A/Brisbane/59/2007 (H1N1) virus replication more effectively than did vaccine alone. Gene expression profiles indicated that, as well as upregulating IFN-stimulated genes (ISGs), CpG ODN enhanced B-cell activation and increased Toll-like receptor 4 (TLR4) and IFN regulatory factor 4 (IRF4) expression, whereas PEG-IFN augmented adaptive immunity by inducing major histocompatibility complex (MHC) transcription and Ras signaling. In contrast, the use of CFA as an adjuvant induced limited ISG expression but increased the transcription of MHC, cell adhesion molecules, and B-cell activation markers. Taken together, our results better characterize the specific molecular pathways leading to adjuvant activity in different adjuvant-mediated influenza virus vaccinations.
Molecular characterization of in vivo adjuvant activity in ferrets vaccinated against influenza virus.
Specimen part, TreatmentView Samples
We have identified a CD57+PD1- CD4 T cell phenotype at the time of transplantation that strongly correlates with subsequesnt development of belatacept-resistant rejection. In this study, we used microarray to determine which genes were upregulated in CD57+ compared to CD57- CD4 T cells.
CD57(+) CD4 T Cells Underlie Belatacept-Resistant Allograft Rejection.
Specimen part, SubjectView Samples
CD8+ T-cells inhibit virus replication in SIV-infected rhesus macaques (RM). However, it is not clear how SIV infection is controlled in germinal center during chronic SIV infection and limited information exists on the characteristics of CXCR5+ CD8 T cells during chronic SIV/HIV infection. In this study, we used functional genomics to investigate characteristic features and potential mechanisms of CXCR5+ and CXCR5- SIV specific CD8 T cells for the control of pathogenic SIV infection. Six chronically SIV infected RMs, three SIVE660 infected and three SIV mac251 infected that are positive for Mamu A01 allele were selected and SIV-specific CXCR5+ and CXCR5- CD8 T cells were sorted based on CXCR5 expression. RNA from sorted cells were extracted and microarray were performed and analysed. Principal component analysis demonstrated that overall gene expression difference between CXCR5+ and CXCR5- SIV-specific CD8 T cells. Interestingly, the CXCR5+ CD8 T cells revealed a distinct gene signature pattern when compared to CXCR5- CD8 T cells. Unlike the CXCR5- CD8 T cells, the CXCR5+ CD8 T cells expressed higher levels of genes associated with Tfh CD4 T cells such as the master transcription factor Bcl6, CD200, and CTLA4 as well as markers associated with Th2 CD4 T cells such as IL-4R (CD124), CCR4, STAT6, NFATC, and IL-10. Effector molecules typically observed in cytotoxic CD8 T cells such as granzyme A, B, and K were expressed at lower levels on CXCR5+ CD8 T cells compared to their CXCR5- counterparts. CXCR5+ CD8 T cells also expressed higher levels of molecules associated with co-stimulation/antigen presentation such as CD40, CD83, 41BBL and MAMU-DRA. The CXCR5+ CD8 also expressed higher levels of inhibitory receptors such as CD200 and SPRY2 but lower levels of other inhibitory receptors CD160 and CD244. The functional consequence of the expression of these molecules is yet to be determined. Additionally, CXCR5+ CD8 T cells expressed higher levels of the anti-apoptotic gene Bcl-2 and lower levels of the pro-apoptotic gene annexin, suggestive of their better survival potential during chronic SIV infection. Collectively, these results demonstrate that SIV specific CXCR5+ CD8 T cells possess a unique gene expression signature compared to SIV-specific CXCR5- CD8 T cells.
Dynamics of SIV-specific CXCR5+ CD8 T cells during chronic SIV infection.
Specimen partView Samples
Natural SIV infection of sooty mangabeys (SMs) does not progress to disease despite chronic virus replication. In contrast to pathogenic SIV infection of rhesus macaques (RMs), chronic SIV infection of SMs is characterized by low immune activation. To elucidate the mechanisms underlying this phenotype, we longitudinally assessed host gene expression in SIV-infected SMs and RMs. We found that acute SIV infection of SMs is consistently associated with a robust innate immune response, including widespread up-regulation of interferon-stimulated genes (ISGs). Our findings indicate that active immune regulatory mechanisms, rather than intrinsically attenuated innate immune responses, underlie the low immuneactivation of chronically SIV-infected SMs.
Global genomic analysis reveals rapid control of a robust innate response in SIV-infected sooty mangabeys.
Sex, Specimen partView Samples
Graft versus host disease (GVHD) is the most common complication of hematopoietic stem cell transplant (HCT). However, our understanding of the molecular pathways that cause this disease remains incomplete, leading to inadequate treatment strategies. To address this, we measured the gene expression profile of non-human primate (NHP) T cells during acute GVHD. This transcriptome analysis enables an unsupervised approach to the identification of targets for disease control using a model with an immune system that closely overlaps with the human and has a high degree of cross-reactivity with human antibody-based therapeutics.
Transcriptome analysis of GVHD reveals aurora kinase A as a targetable pathway for disease prevention.