Deep transcriptional sequencing of mucosal challenge compartment from rhesus macaques acutely infected with simian immunodeficiency virus implicates loss of cell adhesion preceding immune activation
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ABSTRACT: Recent studies of nonhuman primates (NHPs) have suggested that during the acute phase of infection, antiviral mucosal immunity is restricting viral replication in the primary infection compartment. These studies imply that HIV achieves systemic infection as a consequence of a failure in host antiviral immunity. Here, we used high-dose intrarectal inoculation of rhesus macaques with SIVmac251 to examine how the mucosal immune system is overcome by SIV during acute infection. The host response in rectal mucosa was characterized by mRNA deep sequencing (mRNA-seq) at 3 and 12 days post inoculation (DPI) in 4 animals for each time point. The eight RMs were intrarectally challenged with SIVmac251 using 1 mL of a high-dose inoculum (6000 TCID50/mL). SIV inoculates were deposited at a rectal depth of 25 mm from the anus. Baseline rectal samples were obtained 14 days prior to viral challenge by pinch biopsy.
Project description:Recent studies of nonhuman primates (NHPs) have suggested that during the acute phase of infection, antiviral mucosal immunity is restricting viral replication in the primary infection compartment. These studies imply that HIV achieves systemic infection as a consequence of a failure in host antiviral immunity. Here, we used high-dose intrarectal inoculation of rhesus macaques with SIVmac251 to examine how the mucosal immune system is overcome by SIV during acute infection. The host response in rectal mucosa was characterized by mRNA deep sequencing (mRNA-seq) at 3 and 12 days post inoculation (DPI) in 4 animals for each time point.
Project description:In acute HIV infection immune activation may provide target cells and drive virus replication, which innate immunity may limit. Thus, the net effects of inflammatory mediators, including type I interferon (IFN-I), are unclear. Here, we block IFN-I signaling during pathogenic acute SIV infection with an IFN-I receptor antagonist. Delayed antiviral gene expression, increased SIV reservoir, increased CD4 T cell depletion and accelerated progression to AIDS and death ensue despite decreased T cell activation. In contrast, IFNα2a treatment initially upregulates antiviral genes and prevents systemic SIV infection after rectal challenge. Antiviral gene expression normalizes, and infection ensues with fewer transmitted/founder variants. Continued IFNα2a treatment causes delayed antiviral gene expression, increased SIV reservoir and increased CCR5+ CD4 T cell loss. Thus, the precise timing of antiviral gene expression has a profound impact on disease course. The benefits of early antiviral activity outweigh the harms of increased immune activation in acute SIV infection. SRA Study accession: SRP034563, BioProject ID:PRJNA231884
Project description:In acute HIV infection immune activation may provide target cells and drive virus replication, which innate immunity may limit. Thus, the net effects of inflammatory mediators, including type I interferon (IFN-I), are unclear. Here, we block IFN-I signaling during pathogenic acute SIV infection with an IFN-I receptor antagonist. Delayed antiviral gene expression, increased SIV reservoir, increased CD4 T cell depletion and accelerated progression to AIDS and death ensue despite decreased T cell activation. In contrast, IFNα2a treatment initially upregulates antiviral genes and prevents systemic SIV infection after rectal challenge. Antiviral gene expression normalizes, and infection ensues with fewer transmitted/founder variants. Continued IFNα2a treatment causes delayed antiviral gene expression, increased SIV reservoir and increased CCR5+ CD4 T cell loss. Thus, the precise timing of antiviral gene expression has a profound impact on disease course. The benefits of early antiviral activity outweigh the harms of increased immune activation in acute SIV infection.
Project description:Immunization of macaques with simian immunodeficiency virus with deletions in nef (SIV?nef) has been shown to elicit protective immunity to infection by pathogenic SIV, yet our understanding of the mechanisms that orchestrate protection and prevent pathogenesis remains limited. In the study, we utilize whole-genome transcriptional profiling to reveal molecular signatures of protective immunity in circulating CD8+ T cells of rhesus macaques vaccinated with SIVmac239?nef and challenged with pathogenic SIVmac251. Microarrays were used to characterize changes in gene expression in blood CD8+ T cells that occur following vaccination of rhesus macaques with attenuated SIV?nef and subsequent challenge with pathogenic SIVmac251, in comparison to corresponding changes in healthy controls and unvaccinated animals infected with pathogenic SIVmac251 CD8+ T cells were isolated by magnetic beads from the blood of healthy uninfected macaques, macaques vaccinated with SIV?nef, and unvaccinated controls infected with SIVmac251, and used for RNA extraction and hybridization on Affymetrix microarrays. Blood samples from vaccinated animals were collected prior to vaccination, at 3, 20, and 40 weeks following vaccination. After the 40 week vaccination period, macaques were challenged with SIVmac251, and blood was again collected at 3 weeks following challenge. Blood was collected from the unvaccinated controls at 3 weeks following infection with SIVmac251
Project description:Immunization of macaques with simian immunodeficiency virus with deletions in nef (SIVΔnef) has been shown to elicit protective immunity to infection by pathogenic SIV, yet our understanding of the mechanisms that orchestrate protection and prevent pathogenesis remains limited. In the study, we utilize whole-genome transcriptional profiling to reveal molecular signatures of protective immunity in circulating CD8+ T cells of rhesus macaques vaccinated with SIVmac239Δnef and challenged with pathogenic SIVmac251. Microarrays were used to characterize changes in gene expression in blood CD8+ T cells that occur following vaccination of rhesus macaques with attenuated SIV∆nef and subsequent challenge with pathogenic SIVmac251, in comparison to corresponding changes in healthy controls and unvaccinated animals infected with pathogenic SIVmac251
Project description:Identifying immune correlates of protection is a major challenge in AIDS vaccine development. Anti-Envelope antibodies have been considered critical against SIV/HIV acquisition. Here, we evaluated the efficacy of a SHIV vaccine against SIVmac251 challenge, where the role of antibody was excluded as there was no cross-reactivity between SIV and SHIV Envelope antibodies. After eight low-dose rectal challenges with SIVmac251, 12 SHIV-vaccinated animals demonstrated 83% efficacy, compared to six naïve controls, suggesting protection could be achieved in the absence of anti-Envelope antibodies. Interestingly, CD8+ T cells (and some NK cells) were not essential for the preventing viral acquisition, as none of the CD8-depleted macaques were infected by SIVmac251 challenges. Initial investigation of protective innate immunity revealed that protected animals had elevated pathways related to platelet aggregation/activation, and reduced pathways related to interferon and responses to virus. Moreover, higher expression of platelet factor 4 (PF4) on circulating platelet-leukocyte aggregates was associated with reduced viral acquisition. Our data highlighted the importance of innate immunity and may provide new opportunities for novel HIV vaccines or therapeutic strategy development.
Project description:Identifying immune correlates of protection is a major challenge in AIDS vaccine development. Anti-Envelope antibodies have been considered critical against SIV/HIV acquisition. Here, we evaluated the efficacy of a SHIV vaccine against SIVmac251 challenge, where the role of antibody was excluded as there was no cross-reactivity between SIV and SHIV Envelope antibodies. After eight low-dose rectal challenges with SIVmac251, 12 SHIV-vaccinated animals demonstrated 83% efficacy, compared to six naïve controls, suggesting protection could be achieved in the absence of anti-Envelope antibodies. Interestingly, CD8+ T cells (and some NK cells) were not essential for the preventing viral acquisition, as none of the CD8-depleted macaques was infected by SIVmac251 challenges. Initial investigation of protective innate immunity revealed that protected animals had elevated pathways related to platelet aggregation/activation, and reduced pathways related to interferon and responses to virus. Moreover, higher expression of platelet factor 4 (PF4) on circulating platelet-leukocyte aggregates was associated with reduced viral acquisition. Our data highlighted the importance of innate immunity and may provide new opportunities for novel HIV vaccines or therapeutic strategy development.
Project description:The Canarypox/gp120/Alum vaccines decreased the risk of HIV acquisition in humans. We demonstrate here the efficacy of this vaccine regimen also in the SIVmac251 macaque model when we used the alum but not the MF59 adjuvant. Analysis of innate and adaptive cell responses, envelope antibodies Fc profiles and glycoforms demonstrated a lower inflammatory response with alum than MF59. Alum elicited mucosal V2 peptide-specific IgG associated with vaccine efficacy whereas the MF59 induced mucosal V2 peptide-specific IgG associated with increased risk of infection. Alum modulated the expression of 12 genes, 7 of which are part of the RAS pathway, that correlates with vaccine efficacy and were linked to innate responses that preserve mucosal integrity and adaptive mucosal antibody response to V2. Thus, activation of the RAS pathway, preservation of mucosal integrity and mucosal antibody to V2 in concert, reduce the risk of SIVmac251 acquisition. Fifty-four (54) rhesus macaques were randomized into two vaccination groups. One group (n=27) was primed twice with ALVAC-SIV (at week 0 and week 4) and boosted twice with ALVAC-SIV/gp120 in MF59 adjuvant (at week 12 and week 24). The second group (n=27) was primed twice with ALVAC-SIV (at week 0 and week 4) and boosted twice with ALVAC-SIV/gp120 in Alum adjuvant (at week 12 and week 24). Blood samples were taken pre-vaccination, 24 hours after the first prime (post-1st imunization at week 0) and 24 hours after the first boost (post-3rd immunization at week 12). All the samples were taken before SIV challenge. Blood samples were conserved in PAXgene tubes. RNA was extracted and hybridized to Illumina beadchips. technical replicate: P162_P382_post1st, P162_P382_post1st_rep1
Project description:Systemic vaccination with the attenuated virus SIVmac239-∆Nef provides sterilizing or partial protection to rhesus monkeys challenged with WT SIV strains, providing important opportunities to study key immunological components of a protective host response. Here we show that intravenous vaccination with SIVmac239-∆Nef provides two potentially crucial immunological barriers localized at mucosal surfaces that correlate with the vaccine’s protective effects against WT SIVmac251 vaginal challenge: 1) a conditioned and coordinated response from the mucosal epithelium that blunts the early inflammatory and chemotactic signalling cascade that aids virus propagation and expansion; 2) early on-site generation/diversification of SIV-specific Abs from ectopic germinal center-like lymphoid aggregates. This unique host response to WT SIVmac251 in the female reproductive tract of SIVmac239-∆Nef-vaccinated animals points to a multi-layered strategy for a protective host response during immunodeficiency virus exposure—rapid induction of humroal immunity at mucosal surfaces without the deleterious inflammatory side effects tied to innate recognition of virus. This vaccine-induced host response highlights potential key protective mechanisms needed for an effective HIV vaccine Total RNA was isolated from the cervix of 17 Indian Rhesus macaques (3 uninfected animals; 5 unvaccinated animals 4-5 days post vaginal exposure with SIVmac251; 4 SIVmac239-∆Nef-vaccinated animals before challenge; 5 SIVmac239-∆Nef-vaccinated animals 4-5 days post vaginal exposure with SIVmac251) and prepared for hybridization on Affymetrix GeneChip Rhesus Macaque Genome Arrays. Replicate arrays were performed for a number of the samples to minimize assay noise and significant host genes altered during virus exposure in female reproductive tract tissue were identified by their associated q-values (< 0.2) and fold change in expression (> 1.2).
Project description: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 ?4?7-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. SIV negative controls (n=4) and week 12 post SIV infected (n=4) groups of Rhesus macaques and SIV negative controls (n=4) and week 55 post SIV infected (n=4) groups of Sooty mangabeys colorectal tissue biopsies were collected in to RNA later reagent (Qiagen) and were homogenized with syringe and needle method. RNA was extracted with Rneasy mini kit (Qiagen) and was used for microarray experiments. Rhesus GeneChip assays were performed in the Yerkes Microarray Core Facility (www.microarray.emory.edu) , one of the Affymetrix Microarray Core Labs.The 0.5µg of total RNA sample was analyzed on Rhesus Macaque Genome GeneChip that consists of over 52,000 probe sets (Affymetrix, Santa Clara, CA). Target RNA labeling, hybridization and post-hybridization processing were performed following the Affymetrix GeneChip Expression Analysis standard protocols. In brief, The 5 ?g of RNA sample was first reverse-transcribed using T7-Oligo(dT) Promoter Primer and SuperScript II in the first-strand cDNAs synthesis reaction. Following RNase H-mediated second-stranded cDNA synthesis, the double-stranded cDNAs were purified by use of a GeneChip sample clean-up module and served as templates in the generation of biotinylated complementary RNAs (cRNAs) in the presence of T7 RNA Polymerase and a biotinylated nucleotide analog/ribonucleotide mix by in vitro transcription (IVT) reaction. The biotinylated cRNAs were cleaned up, fragmented, and hybridized to the rhesus macaque expression arrays at 45°C for 16 h with constant rotation at 60 rpm. The gene chips were then washed and stained with Affymetrix fluidics stations 450 and scanned on Affymetrix scanner 3000. The images are processed to collect raw data with GeneChip Operating Software (GCOS) 1.4. Tissue: Colorectal tissue Time after SIV infection: 12 weeks for SIV infected Rhesus macaques, 55 weeks for Sooty mangabeys Infection: SIVmac251 infection for Rhesus macaques, SIVsm infection for Sooty mangabeys