scholarly journals Kinetics of Early Innate Immune Activation during HIV-1 Infection of Humanized Mice

2019 ◽  
Vol 93 (11) ◽  
Author(s):  
Jessica Katy Skelton ◽  
Ana Maria Ortega-Prieto ◽  
Steve Kaye ◽  
Jose Manuel Jimenez-Guardeño ◽  
Jane Turner ◽  
...  
Keyword(s):  
Immune Responses ◽  
Immune Activation ◽  
Innate Immune ◽  
Model Systems ◽  
Humanized Mice ◽  
Type I ◽  
Innate Immune Activation ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection is associated with aberrant immune activation; however, most model systems for HIV-1 have been used during established infection. Here, we utilize ultrasensitive HIV-1 quantification to delineate early events during the eclipse, burst, and chronic phases of HIV-1 infection in humanized mice. We show that very early in infection, HIV-1 suppresses peripheral type I interferon (IFN) and interferon-stimulated gene (ISG) responses, including the HIV-1 restriction factor IFI44. At the peak of innate immune activation, prior to CD4 T cell loss, HIV-1 infection differentially affects peripheral and lymphoid Toll-like receptor (TLR) expression profiles in T cells and macrophages. This results in a trend toward an altered activation of nuclear factor κB (NF-κB), TANK-binding kinase 1 (TBK1), and interferon regulatory factor 3 (IRF3). The subsequent type I and III IFN responses result in preferential induction of peripheral ISG responses. Following this initial innate immune activation, peripheral expression of the HIV-1 restriction factor SAM domain- and HD domain-containing protein 1 (SAMHD1) returns to levels below those observed in uninfected mice, suggesting that HIV-1 interferes with their basal expression. However, peripheral cells still retain their responsiveness to exogenous type I IFN, whereas splenic cells show a reduction in select ISGs in response to IFN. This demonstrates the highly dynamic nature of very early HIV-1 infection and suggests that blocks to the induction of HIV-1 restriction factors contribute to the establishment of viral persistence. IMPORTANCE Human immunodeficiency virus type 1 (HIV-1) infection is restricted to humans and some nonhuman primates (e.g., chimpanzee and gorilla). Alternative model systems based on simian immunodeficiency virus (SIV) infection of macaques are available but do not recapitulate all aspects of HIV-1 infection and disease. Humanized mice, which contain a human immune system, can be used to study HIV-1, but only limited information on early events and immune responses is available to date. Here, we describe very early immune responses to HIV-1 and demonstrate a suppression of cell-intrinsic innate immunity. Furthermore, we show that HIV-1 infection interacts differently with innate immune responses in blood and lymphoid organs.

scholarly journals A Novel Phenotype Links HIV-1 Capsid Stability to cGAS-Mediated DNA Sensing

2019 ◽  
Vol 93 (16) ◽  
Author(s):  
Mohammad Adnan Siddiqui ◽  
Akatsuki Saito ◽  
Upul D. Halambage ◽  
Damien Ferhadian ◽  
Douglas K. Fischer ◽  
...  
Keyword(s):  
Immune Activation ◽  
Innate Immune ◽  
Wild Type Virus ◽  
Type I ◽  
Dna Sensing ◽  
Viral Dna ◽  
Innate Immune Activation ◽  
Naturally Occurring ◽  
Capsid Stability ◽  
Hiv 1

ABSTRACTThe HIV-1 capsid executes essential functions that are regulated by capsid stability and host factors. In contrast to increasing knowledge on functional roles of capsid-interacting host proteins during postentry steps, less is known about capsid stability and its impact on intracellular events. Here, using the antiviral compound PF-3450074 (PF74) as a probe for capsid function, we uncovered a novel phenotype of capsid stability that has a profound effect on innate sensing of viral DNA by the DNA sensor cGAS. A single mutation, R143A, in the capsid protein conferred resistance to high concentrations of PF74, without affecting capsid binding to PF74. A cell-free assay showed that the R143A mutant partially counteracted the capsid-destabilizing activity of PF74, pointing to capsid stabilization as a resistance mechanism for the R143A mutant. In monocytic THP-1 cells, the R143A virus, but not the wild-type virus, suppressed cGAS-dependent innate immune activation. These results suggest that capsid stabilization improves the shielding of viral DNA from innate sensing. We found that a naturally occurring transmitted founder (T/F) variant shares the same properties as the R143A mutant with respect to PF74 resistance and DNA sensing. Imaging assays revealed delayed uncoating kinetics of this T/F variant and the R143A mutant. All these phenotypes of this T/F variant were controlled by a genetic polymorphism located at the trimeric interface between capsid hexamers, thus linking these capsid-dependent properties. Overall, this work functionally connects capsid stability to innate sensing of viral DNA and reveals naturally occurring phenotypic variation in HIV-1 capsid stability.IMPORTANCEThe HIV-1 capsid, which is made from individual viral capsid proteins (CA), is a target for a number of antiviral compounds, including the small-molecule inhibitor PF74. In the present study, we utilized PF74 to identify a transmitted/founder (T/F) strain that shows increased capsid stability. Interestingly, PF74-resistant variants prevented cGAS-dependent innate immune activation under a condition where the other T/F strains induced type I interferon. These observations thus reveal a new CA-specific phenotype that couples capsid stability to viral DNA recognition by cytosolic DNA sensors.

scholarly journals LPS-induced down-regulation of signal regulatory protein α contributes to innate immune activation in macrophages

2007 ◽  
Vol 204 (11) ◽  
pp. 2719-2731 ◽  
Author(s):  
Xiao-Ni Kong ◽  
He-Xin Yan ◽  
Lei Chen ◽  
Li-Wei Dong ◽  
Wen Yang ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Immune Responses ◽  
Immune Activation ◽  
Endotoxic Shock ◽  
Regulatory Protein ◽  
Innate Immune ◽  
Host Cells ◽  
Type I ◽  
Innate Immune Responses ◽  
Innate Immune Activation

Activation of the mitogen-activated protein kinases (MAPKs) and nuclear factor κB (NF-κB) cascades after Toll-like receptor (TLR) stimulation contributes to innate immune responses. Signal regulatory protein (SIRP) α, a member of the SIRP family that is abundantly expressed in macrophages, has been implicated in regulating MAPK and NF-κB signaling pathways. In addition, SIRPα can negatively regulate the phagocytosis of host cells by macrophages, indicating an inhibitory role of SIRPα in innate immunity. We provide evidences that SIRPα is an essential endogenous regulator of the innate immune activation upon lipopolysaccharide (LPS) exposure. SIRPα expression was promptly reduced in macrophages after LPS stimulation. The decrease in SIRPα expression levels was required for initiation of LPS-induced innate immune responses because overexpression of SIRPα reduced macrophage responses to LPS. Knockdown of SIRPα caused prolonged activation of MAPKs and NF-κB pathways and augmented production of proinflammatory cytokines and type I interferon (IFN). Mice transferred with SIRPα-depleted macrophages were highly susceptible to endotoxic shock, developing multiple organ failure and exhibiting a remarkable increase in mortality. SIRPα may accomplish this mainly through its association and sequestration of the LPS signal transducer SHP-2. Thus, SIRPα functions as a biologically important modulator of TLR signaling and innate immunity.

scholarly journals Toll-Like Receptor (TLR) Signaling Enables Cyclic GMP-AMP Synthase (cGAS) Sensing of HIV-1 Infection in Macrophages

mBio ◽  
2021 ◽  
Author(s):  
Mohammad Adnan Siddiqui ◽  
Masahiro Yamashita
Keyword(s):  
Immune Responses ◽  
Cyclic Gmp ◽  
Immune Activation ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Toll Like Receptor ◽  
Tlr Signaling ◽  
Innate Immune Activation ◽  
Hiv 1

Innate immune activation is a hallmark of HIV-1 pathogenesis. Thus, it is critical to understand how HIV-1 infection elicits innate immune responses.

scholarly journals The Landscape of IFN/ISG Signaling in HIV-1-Infected Macrophages and Its Possible Role in the HIV-1 Latency

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2378
Author(s):  
Masyelly Rojas ◽  
Patricia Luz-Crawford ◽  
Ricardo Soto-Rifo ◽  
Sebastián Reyes-Cerpa ◽  
Daniela Toro-Ascuy
Keyword(s):  
Innate Immune ◽  
Viral Fitness ◽  
Type I Interferons ◽  
Type I ◽  
Type I Ifn ◽  
Viral Reservoirs ◽  
Immunodeficiency Virus ◽  
Latent Hiv ◽  
Hiv 1

A key characteristic of Human immunodeficiency virus type 1 (HIV-1) infection is the generation of latent viral reservoirs, which have been associated with chronic immune activation and sustained inflammation. Macrophages play a protagonist role in this context since they are persistently infected while being a major effector of the innate immune response through the generation of type-I interferons (type I IFN) and IFN-stimulated genes (ISGs). The balance in the IFN signaling and the ISG induction is critical to promote a successful HIV-1 infection. Classically, the IFNs response is fine-tuned by opposing promotive and suppressive signals. In this context, it was described that HIV-1-infected macrophages can also synthesize some antiviral effector ISGs and, positive and negative regulators of the IFN/ISG signaling. Recently, epitranscriptomic regulatory mechanisms were described, being the N6-methylation (m6A) modification on mRNAs one of the most relevant. The epitranscriptomic regulation can affect not only IFN/ISG signaling, but also type I IFN expression, and viral fitness through modifications to HIV-1 RNA. Thus, the establishment of replication-competent latent HIV-1 infected macrophages may be due to non-classical mechanisms of type I IFN that modulate the activation of the IFN/ISG signaling network.

scholarly journals HIV-1 Is a Poor Inducer of Innate Immune Responses

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Oya Cingöz ◽  
Stephen P. Goff
Keyword(s):  
Human Immunodeficiency Virus ◽  
Immune Responses ◽  
Cell Lines ◽  
Human Immunodeficiency Virus Type ◽  
Innate Immune ◽  
Innate Immune Responses ◽  
Immunodeficiency Virus ◽  
Cellular Sensors ◽  
Hiv 1

ABSTRACT Effective host immune responses against viral infection rely on the detection of the virus, activation of downstream signaling pathways, and the secretion of interferons (IFNs) and other cytokines. Many viruses can potently stimulate these responses, whereas the immune response against human immunodeficiency virus type 1 (HIV-1) remains relatively less well characterized. Here we show that HIV-1 infection with reporter viruses does not activate sensing pathways in cell lines and primary cells that are otherwise responsive to foreign nucleic acids. After entry into cells, reverse transcription and reporter expression occur without the virus ever being detected by cellular sensors or stimulating an interferon response. Using multiple methods, including the use of reporter cell lines for type I IFN and NF-κB pathway activation, quantifying mRNA levels for IFN-stimulated genes (ISGs), and assaying for markers of innate immune activation, we show that single-round pseudotyped HIV-1-based reporter viruses fail to induce innate immune responses. IMPORTANCE Human immunodeficiency virus type 1 (HIV-1) continues to be a major burden to human health worldwide. How infected cells recognize and respond to HIV-1 infection is important in order to better understand the biology of the virus and the cellular pathways activated upon infection and to identify potential targets that interfere with viral replication. In this study, we investigated innate immune responses of different cell types following infection with single-cycle (replication-defective) HIV-1 reporter virus. We report that infection with a commonly used HIV-1 strain (lacking the env, nef, and vpr genes) does not measurably activate cellular defense mechanisms and that the virus is able to avoid recognition by cellular sensors.

scholarly journals ADAR1 function affects HPV replication and is associated to recurrent human papillomavirus-induced dysplasia in HIV coinfected individuals

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Maria Pujantell ◽  
Roger Badia ◽  
Iván Galván-Femenía ◽  
Edurne Garcia-Vidal ◽  
Rafael de Cid ◽  
...  
Keyword(s):  
Human Papillomavirus ◽  
Immune Activation ◽  
Hpv Infection ◽  
Innate Immune ◽  
Type I ◽  
Innate Immune Activation ◽  
Enhanced Expression

AbstractInfection by human papillomavirus (HPV) alters the microenvironment of keratinocytes as a mechanism to evade the immune system. A-to-I editing by ADAR1 has been reported to regulate innate immunity in response to viral infections. Here, we evaluated the role of ADAR1 in HPV infection in vitro and in vivo. Innate immune activation was characterized in human keratinocyte cell lines constitutively infected or not with HPV. ADAR1 knockdown induced an innate immune response through enhanced expression of RIG-I-like receptors (RLR) signaling cascade, over-production of type-I IFNs and pro-inflammatory cytokines. ADAR1 knockdown enhanced expression of HPV proteins, a process dependent on innate immune function as no A-to-I editing could be identified in HPV transcripts. A genetic association study was performed in a cohort of HPV/HIV infected individuals followed for a median of 6 years (range 0.1–24). We identified the low frequency haplotype AACCAT significantly associated with recurrent HPV dysplasia, suggesting a role of ADAR1 in the outcome of HPV infection in HIV+ individuals. In summary, our results suggest that ADAR1-mediated innate immune activation may influence HPV disease outcome, therefore indicating that modification of innate immune effectors regulated by ADAR1 could be a therapeutic strategy against HPV infection.

scholarly journals Author response: HIV-1 Vpr antagonizes innate immune activation by targeting karyopherin-mediated NF-κB/IRF3 nuclear transport

2020 ◽  
Author(s):  
Hataf Khan ◽  
Rebecca P Sumner ◽  
Jane Rasaiyaah ◽  
Choon Ping Tan ◽  
Maria Teresa Rodriguez-Plata ◽  
...  
Keyword(s):  
Immune Activation ◽  
Nuclear Transport ◽  
Innate Immune ◽  
Author Response ◽  
Innate Immune Activation ◽  
Hiv 1

scholarly journals CD4 Binding Affinity Determines Human Immunodeficiency Virus Type 1-Induced Alpha Interferon Production in Plasmacytoid Dendritic Cells

2008 ◽  
Vol 82 (17) ◽  
pp. 8900-8905 ◽  
Author(s):  
Sabrina Haupt ◽  
Norbert Donhauser ◽  
Chawaree Chaipan ◽  
Philipp Schuster ◽  
Bridget Puffer ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Dendritic Cells ◽  
Binding Affinity ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Plasmacytoid Dendritic Cells ◽  
Type I ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT Plasmacytoid dendritic cells (PDC) are major producers of type I interferons (IFN) in response to human immunodeficiency virus type 1 (HIV-1) infection. To better define the underlying mechanisms, we studied the magnitude of alpha IFN (IFN-α) induction by recombinant viruses containing changes in the Env protein that impair or disrupt CD4 binding or expressing primary env alleles with differential coreceptor tropism. We found that the CD4 binding affinity but not the viral coreceptor usage is critical for the attachment of autofluorescing HIV-1 to PDC and for subsequent IFN-α induction. Our results illustrate the importance of the gp120-CD4 interaction in determining HIV-1-induced immune stimulation via IFN-α production.

scholarly journals Enhanced HIV-1 immunotherapy by commonly arising antibodies that target virus escape variants

2014 ◽  
Vol 211 (12) ◽  
pp. 2361-2372 ◽  
Author(s):  
Florian Klein ◽  
Lilian Nogueira ◽  
Yoshiaki Nishimura ◽  
Ganesh Phad ◽  
Anthony P. West ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Neutralizing Antibodies ◽  
Viral Escape ◽  
Humanized Mice ◽  
Broadly Neutralizing Antibodies ◽  
Virus Escape ◽  
Immunodeficiency Virus ◽  
Shiv Infection ◽  
Hiv 1

Antibody-mediated immunotherapy is effective in humanized mice when combinations of broadly neutralizing antibodies (bNAbs) are used that target nonoverlapping sites on the human immunodeficiency virus type 1 (HIV-1) envelope. In contrast, single bNAbs can control simian–human immunodeficiency virus (SHIV) infection in immune-competent macaques, suggesting that the host immune response might also contribute to the control of viremia. Here, we investigate how the autologous antibody response in intact hosts can contribute to the success of immunotherapy. We find that frequently arising antibodies that normally fail to control HIV-1 infection can synergize with passively administered bNAbs by preventing the emergence of bNAb viral escape variants.

scholarly journals Induction of Humoral Immune Responses following Vaccination with Envelope-Containing, Formaldehyde-Treated, Thermally Inactivated Human Immunodeficiency Virus Type 1

2005 ◽  
Vol 79 (8) ◽  
pp. 4927-4935 ◽  
Author(s):  
B. Poon ◽  
J. T. Safrit ◽  
H. McClure ◽  
C. Kitchen ◽  
J. F. Hsu ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Thermal Treatment ◽  
Immune Responses ◽  
Human Immunodeficiency Virus Type ◽  
Virus Type ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Immunodeficiency Virus ◽  
Hiv 1

ABSTRACT The lack of success of subunit human immunodeficiency virus type 1 (HIV-1) vaccines to date suggests that multiple components or a complex virion structure may be required. We previously demonstrated retention of the major conformational epitopes of HIV-1 envelope following thermal treatment of virions. Moreover, antibody binding to some of these epitopes was significantly enhanced following thermal treatment. These included the neutralizing epitopes identified by monoclonal antibodies 1b12, 2G12, and 17b, some of which have been postulated to be partially occluded or cryptic in native virions. Based upon this finding, we hypothesized that a killed HIV vaccine could be derived to elicit protective humoral immune responses. Shedding of HIV-1 envelope has been described for some strains of HIV-1 and has been cited as one of the major impediments to developing an inactivated HIV-1 vaccine. In the present study, we demonstrate that treatment of virions with low-dose formaldehyde prior to thermal inactivation retains the association of viral envelope with virions. Moreover, mice and nonhuman primates vaccinated with formaldehyde-treated, thermally inactivated virions produce antibodies capable of neutralizing heterologous strains of HIV in peripheral blood mononuclear cell-, MAGI cell-, and U87-based infectivity assays. These data indicate that it is possible to create an immunogen by using formaldehyde-treated, thermally inactivated HIV-1 virions to induce neutralizing antibodies. These findings have broad implications for vaccine development.

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