Journal of Immunological Methods
Richardson, Z;Deleage, C;Tutuka, C;Walkiewicz, M;Del Río-Estrada, P;Pascoe, R;Evans, V;Reyesteran, G;Gonzales, M;Roberts-Thomson, S;González-Navarro, M;Torres-Ruiz, F;Estes, J;Lewin, S;Cameron, P;
| DOI: 10.1016/j.jim.2021.113198
The main barrier to a cure for HIV is the persistence of long-lived and proliferating latently infected CD4+ T-cells despite antiretroviral therapy (ART). Latency is well characterized in multiple CD4+ T-cell subsets, however, the contribution of regulatory T-cells (Tregs) expressing FoxP3 as well as immune checkpoints (ICs) PD-1 and CTLA-4 as targets for productive and latent HIV infection in people living with HIV on suppressive ART is less well defined. We used multiplex detection of HIV DNA and RNA with immunohistochemistry (mIHC) on formalin-fixed paraffin embedded (FFPE) cells to simultaneously detect HIV RNA and DNA and cellular markers. HIV DNA and RNA were detected by in situ hybridization (ISH) (RNA/DNAscope) and IHC was used to detect cellular markers (CD4, PD-1, FoxP3, and CTLA-4) by incorporating the tyramide system amplification (TSA) system. We evaluated latently infected cell lines, a primary cell model of HIV latency and excisional lymph node (LN) biopsies collected from people living with HIV (PLWH) on and off ART. We clearly detected infected cells that coexpressed HIV RNA and DNA (active replication) and DNA only (latently infected cells) in combination with IHC markers in the in vitro infection model as well as LN tissue from PLWH both on and off ART. Combining ISH targeting HIV RNA and DNA with IHC provides a platform to detect and quantify HIV persistence within cells identified by multiple markers in tissue samples from PLWH on ART or to study HIV latency.
Gumbs, SBH;Kübler, R;Gharu, L;Schipper, PJ;Borst, AL;Snijders, GJLJ;Ormel, PR;van Berlekom, AB;Wensing, AMJ;de Witte, LD;Nijhuis, M;
PMID: 35138593 | DOI: 10.1007/s13365-021-01049-w
HIV persistence in the CNS despite antiretroviral therapy may cause neurological disorders and poses a critical challenge for HIV cure. Understanding the pathobiology of HIV-infected microglia, the main viral CNS reservoir, is imperative. Here, we provide a comprehensive comparison of human microglial culture models: cultured primary microglia (pMG), microglial cell lines, monocyte-derived microglia (MDMi), stem cell-derived microglia (iPSC-MG), and microglia grown in 3D cerebral organoids (oMG) as potential model systems to advance HIV research on microglia. Functional characterization revealed phagocytic capabilities and responsiveness to LPS across all models. Microglial transcriptome profiles of uncultured pMG showed the highest similarity to cultured pMG and oMG, followed by iPSC-MG and then MDMi. Direct comparison of HIV infection showed a striking difference, with high levels of viral replication in cultured pMG and MDMi and relatively low levels in oMG resembling HIV infection observed in post-mortem biopsies, while the SV40 and HMC3 cell lines did not support HIV infection. Altogether, based on transcriptional similarities to uncultured pMG and susceptibility to HIV infection, MDMi may serve as a first screening tool, whereas oMG, cultured pMG, and iPSC-MG provide more representative microglial culture models for HIV research. The use of current human microglial cell lines (SV40, HMC3) is not recommended.
Human anogenital monocyte-derived dendritic cells and langerin+cDC2 are major HIV target cells
Rhodes, JW;Botting, RA;Bertram, KM;Vine, EE;Rana, H;Baharlou, H;Vegh, P;O'Neil, TR;Ashhurst, AS;Fletcher, J;Parnell, GP;Graham, JD;Nasr, N;Lim, JJK;Barnouti, L;Haertsch, P;Gosselink, MP;Di Re, A;Reza, F;Ctercteko, G;Jenkins, GJ;Brooks, AJ;Patrick, E;Byrne, SN;Hunter, E;Haniffa, MA;Cunningham, AL;Harman, AN;
PMID: 33846309 | DOI: 10.1038/s41467-021-22375-x
Tissue mononuclear phagocytes (MNP) are specialised in pathogen detection and antigen presentation. As such they deliver HIV to its primary target cells; CD4 T cells. Most MNP HIV transmission studies have focused on epithelial MNPs. However, as mucosal trauma and inflammation are now known to be strongly associated with HIV transmission, here we examine the role of sub-epithelial MNPs which are present in a diverse array of subsets. We show that HIV can penetrate the epithelial surface to interact with sub-epithelial resident MNPs in anogenital explants and define the full array of subsets that are present in the human anogenital and colorectal tissues that HIV may encounter during sexual transmission. In doing so we identify two subsets that preferentially take up HIV, become infected and transmit the virus to CD4 T cells; CD14+CD1c+ monocyte-derived dendritic cells and langerin-expressing conventional dendritic cells 2 (cDC2).
Plasmacytoid dendritic cells have divergent effects on HIV infection of initial target cells and induce a pro-retention phenotype
Tong, O;Duette, G;O'Neil, TR;Royle, CM;Rana, H;Johnson, B;Popovic, N;Dervish, S;Brouwer, MAE;Baharlou, H;Patrick, E;Ctercteko, G;Palmer, S;Lee, E;Hunter, E;Harman, AN;Cunningham, AL;Nasr, N;
PMID: 33872331 | DOI: 10.1371/journal.ppat.1009522
Although HIV infection inhibits interferon responses in its target cells in vitro, interferon signatures can be detected in vivo soon after sexual transmission, mainly attributed to plasmacytoid dendritic cells (pDCs). In this study, we examined the physiological contributions of pDCs to early HIV acquisition using coculture models of pDCs with myeloid DCs, macrophages and the resting central, transitional and effector memory CD4 T cell subsets. pDCs impacted infection in a cell-specific manner. In myeloid cells, HIV infection was decreased via antiviral effects, cell maturation and downregulation of CCR5 expression. In contrast, in resting memory CD4 T cells, pDCs induced a subset-specific increase in intracellular HIV p24 protein expression without any activation or increase in CCR5 expression, as measured by flow cytometry. This increase was due to reactivation rather than enhanced viral spread, as blocking HIV entry via CCR5 did not alter the increased intracellular p24 expression. Furthermore, the load and proportion of cells expressing HIV DNA were restricted in the presence of pDCs while reverse transcriptase and p24 ELISA assays showed no increase in particle associated reverse transcriptase or extracellular p24 production. In addition, pDCs also markedly induced the expression of CD69 on infected CD4 T cells and other markers of CD4 T cell tissue retention. These phenotypic changes showed marked parallels with resident memory CD4 T cells isolated from anogenital tissue using enzymatic digestion. Production of IFNα by pDCs was the main driving factor for all these results. Thus, pDCs may reduce HIV spread during initial mucosal acquisition by inhibiting replication in myeloid cells while reactivating latent virus in resting memory CD4 T cells and retaining them for immune clearance.
The Contributions of Clinical Pharmacology to HIV Cure Research
Clinical pharmacology and therapeutics
Fletcher, CV;Dyavar, SR;Acharya, A;Byrareddy, SN;
PMID: 33763860 | DOI: 10.1002/cpt.2237
Combination antiretroviral therapy (ART) can suppress plasma HIV-RNA to < 50 copies/mL, decrease HIV transmission, reduce mortality, and improve quality of life for people living with HIV. ART cannot, however, eliminate HIV from an infected individual. The primary barrier to cure HIV infection is the multiple reservoir sites, including adipose tissue, bone marrow, central nervous system, liver, lungs, male and female reproductive system, secondary lymph nodes, and gut-associated lymphoid tissue, established 1 to 2 weeks after acquisition of HIV. Additional challenges include understanding the mechanism(s) by which HIV is maintained at low or undetectable levels and developing treatments that will eradicate or produce a sustained suppression of virus without ART. To date, the most extensive clinical investigations of cure strategies have been the shock-and-kill approach using histone deacetylase inhibitors (HDACis) to induce reactivation of latent HIV. Despite evidence for HIV latency reversal, HDACis alone have not decreased the size of the latent reservoir. Clinical pharmacologic explanations for these results include a low inhibitory quotient (i.e., low potency) within the reservoir sites and intrinsic (e.g., sex differences and reservoir size) and extrinsic (physiochemical and pharmacokinetic drug characteristics) factors. We offer an outline of desired clinical pharmacologic attributes for therapeutics intended for clinical HIV cure research and call for research teams to have early and ongoing involvement of clinical pharmacologists. We believe such a collective effort will provide a solid scientific basis and hope for reaching the goal of a cure for HIV infection.
Isnard, S;Fombuena, B;Ouyang, J;Royston, L;Lin, J;Bu, S;Sheehan, N;Lakatos, PL;Bessissow, T;Chomont, N;Klein, M;Lebouché, B;Costiniuk, CT;Routy, B;Marette, A;Routy, JP;Camu Camu Study Group, ;
PMID: 35039291 | DOI: 10.1136/bmjopen-2021-053081
Despite the success of antiretroviral therapy (ART) in transforming HIV disease into a chronic infection, people living with HIV (PLWH) remain at risk for various non-AIDS inflammatory comorbidities. Risk of non-AIDS comorbidities is associated with gut dysbiosis, epithelial gut damage and subsequent microbial translocation, and increased activation of both circulating CD4+ and CD8+ T-cells. Therefore, in addition to ART, novel gut microbiota-modulating therapies could aid in reducing inflammation and immune activation, gut damage, and microbial translocation. Among various gut-modulation strategies under investigation, the Amazonian fruit Camu Camu (CC) presents itself as a prebiotic candidate based on its anti-inflammatory and antioxidant properties in animal models and tobacco smokers.A total of 22 PLWH on ART for more than 2 years, with a viral load <50 copies/mL, a CD4 +count >200 and a CD4+/CD8 +ratio <1 (suggesting increased inflammation and risk for non-AIDS comorbidities), will be recruited in a single arm, non-randomised, interventional pilot trial. We will assess tolerance and effect of supplementation with CC in ART-treated PLWH on reducing gut damage, microbial translocation, inflammation and HIV latent reservoir by various assays.The Canadian Institutes of Health Research (CIHR)/Canadian HIV Trials Network (CTN) pilot trial protocol CTNPT032 was approved by the Natural and Non-prescription Health Products Directorate of Health Canada and the research ethics board of the McGill university Health Centre committee (number 2020-5903). Results will be made available as free access through publications in peer-reviewed journals and through the CIHR/CTN website.NCT04058392.
Hsu DC, Sunyakumthorn P, Wegner M, Schuetz A, Silsorn D, Estes JD, Deleage C, Tomusange K, Lakhashe SK, Ruprecht RM, Lombardini E, Im-Erbsin R, Kuncharin Y, Phuang-Ngern Y, Inthawong D, Chuenarom W, Burke R, Robb ML, Ndhlovu LC, Ananworanich J, Valcour V,
PMID: 29563297 | DOI: 10.1128/JVI.00222-18
Studies utilizing highly pathogenic simian immunodeficiency virus (SIV) and simian-human immunodeficiency virus (SHIV) have largely focused on the immunopathology of the central nervous system (CNS) during end-stage neuro AIDS and SIV encephalitis. However, this may not model pathophysiology in earlier stages of infection. In this non-accelerated SHIV model, plasma SHIV RNA levels and peripheral blood and colonic CD4 T+ cell counts mirrored early HIV infection in humans. At 12 weeks post infection, cerebrospinal fluid (CSF) detection of SHIV RNA and elevations in IP-10 and MCP-1 reflected a discrete neurovirologic process. Immunohistochemical staining revealed a diffuse, low-level CD3+, CD4- cellular infiltrate in the brain parenchyma, without a concomitant increase in CD68/CD163+ monocytes, macrophages and activated microglial cells. Rare SHIV-infected cells in the brain parenchyma and meninges were identified by RNAscope®in situhybridization. In the meninges, there was also a trend toward increased CD4+ infiltration in SHIV-infected animals, but no differences in CD68/CD163+ cells between SHIV-infected and uninfected control animals. These data suggest that in a model that closely recapitulates human disease, CNS inflammation and SHIV in CSF may be predominantly mediated by T-cell mediated processes during early infection in both brain parenchyma and meninges. Because SHIV expresses an HIV rather than SIV envelope, this model could inform studies to understand potential HIV cure strategies targeting the HIV envelope.IMPORTANCE Animal models of the neurologic effects of HIV are needed because brain pathology is difficult to assess in humans. Many current models focus on the effects of late stage disease utilizing simian immunodeficiency virus (SIV). In the era of antiretroviral therapy, manifestations of late stage HIV are less common. Furthermore, new interventions such as monoclonal antibodies and therapeutic vaccinations target HIV envelope. We therefore describe a new model of central nervous system involvement in rhesus macaques infected with simian-human immunodeficiency virus (SHIV) expressing HIV envelope in earlier, less aggressive stages of disease. Here, we demonstrate that SHIV mimics the early clinical course in humans, and that early neurologic inflammation is characterized by predominantly T cell mediated inflammation, accompanied by SHIV infection in the brain and meninges. This model can be utilized to assess the effect of novel therapies targeted to HIV envelope on reducing brain inflammation before end stage disease.
Vine, EE;Rhodes, JW;Warner van Dijk, FA;Byrne, SN;Bertram, KM;Cunningham, AL;Harman, AN;
PMID: 35173293 | DOI: 10.1038/s41385-022-00492-0
In tissue, mononuclear phagocytes (MNP) are comprised of Langerhans cells, dendritic cells, macrophages and monocyte-derived cells. They are the first immune cells to encounter HIV during transmission and transmit the virus to CD4 T cells as a consequence of their antigen presenting cell function. To understand the role these cells play in transmission, their phenotypic and functional characterisation is important. With advancements in high parameter single cell technologies, new MNPs subsets are continuously being discovered and their definition and classification is in a state of flux. This has important implications for our knowledge of HIV transmission, which requires a deeper understanding to design effective vaccines and better blocking strategies. Here we review the historical research of the role MNPs play in HIV transmission up to the present day and revaluate these studies in the context of our most recent understandings of the MNP system.
In Situ Characterization of Human Lymphoid Tissue Immune Cells by Multispectral Confocal Imaging and Quantitative Image Analysis; Implications for HIV Reservoir Characterization
Moysi, E;Del Rio Estrada, PM;Torres-Ruiz, F;Reyes-Terán, G;Koup, RA;Petrovas, C;
PMID: 34177929 | DOI: 10.3389/fimmu.2021.683396
CD4 T cells are key mediators of adaptive immune responses during infection and vaccination. Within secondary lymphoid organs, helper CD4 T cells, particularly those residing in germinal centers known as follicular helper T cells (Tfh), provide critical help to B-cells to promote their survival, isotype switching and selection of high affinity memory B-cells. On the other hand, the important role of Tfh cells for the maintenance of HIV reservoir is well documented. Thus, interrogating and better understanding the tissue specific micro-environment and immune subsets that contribute to optimal Tfh cell differentiation and function is important for designing successful prevention and cure strategies. Here, we describe the development and optimization of eight multispectral confocal microscopy immunofluorescence panels designed for in depth characterization and immune-profiling of relevant immune cells in formalin-fixed paraffin-embedded human lymphoid tissue samples. We provide a comprehensive library of antibodies to use for the characterization of CD4+ T-cells -including Tfh and regulatory T-cells- as well as CD8 T-cells, B-cells, macrophages and dendritic cells and discuss how the resulting multispectral confocal datasets can be quantitatively dissected using the HistoCytometry pipeline to collect information about relative frequencies and immune cell spatial distributions. Cells harboring actively transcribed virus are analyzed using an in-situ hybridization assay for the characterization of HIV mRNA positive cells in combination with additional protein markers (multispectral RNAscope). The application of this methodology to lymphoid tissues offers a means to interrogate multiple relevant immune cell targets simultaneously at increased resolution in a reproducible manner to guide CD4 T-cell studies in infection and vaccination.
Quantitative Imaging Analysis of the Spatial Relationship between Antiretrovirals, RT-SHIV RNA, and Collagen in the Mesenteric Lymph Nodes of Nonhuman Primates
Antimicrobial agents and chemotherapy
Scholz, EMB;Mwangi, JN;De la Cruz, G;Nekorchuk, M;Chan, CN;Busman-Sahay, K;Adamson, L;Luciw, P;Fedoriw, Y;Estes, JD;Rosen, EP;Kashuba, ADM;
PMID: 33782003 | DOI: 10.1128/AAC.00019-21
HIV persistence in tissue reservoirs is a major barrier to HIV cure. While antiretrovirals (ARVs) suppress viral replication, antiretroviral therapy (ART) interruption results in rapid rebound viremia that may originate from lymphoid tissues. To understand the relationship between anatomic distribution of ARV exposure and viral expression in lymph nodes, we performed mass spectrometry imaging (MSI) of 6 ARVs, RNAscope in situ hybridization for viral RNA, and immunohistochemistry of collagen in mesenteric lymph nodes from 8 uninfected and 10 reverse transcriptase-simian/human immunodeficiency virus (RT-SHIV) infected rhesus macaque nonhuman primates (NHPs) dosed to steady-state with combination ART. MATLAB-based quantitative imaging analysis was used to evaluate spatial and pharmacologic relationships between these ARVs, viral RNA (both vRNA+ cells and FDC-bound virions) and collagen deposition. Using MSI, 31% of mesenteric lymph node tissue area was not covered by any ARV. Additionally, 28% of FDC-trapped virions and 21% of infected cells were not exposed to any detected ARV. Of the 69% of tissue area that was covered by cumulative ART exposure, nearly 100% of concentrations were greater than in vitro IC50 values; however, 52% of total tissue coverage was from only one ARV, primarily maraviroc. Collagen covered ∼35% of tissue area, but did not influence ARV distribution heterogeneity. Our findings are consistent with our hypothesis that ARV distribution, in addition to total-tissue drug concentration, must be considered when evaluating viral persistence in lymph nodes and other reservoir tissues.
Hsu DC, Wegner MD, Sunyakumthorn P, Silsorn D, Tayamun S, Inthawong D, Kuncharin Y, Im-Erbsin R, Ege C, O'Connell RJ, Michael NL, Ndhlovu LC, Vasan S.
PMID: 28748665 | DOI: 10.1111/jmp.12298
Limited longitudinal data exist on the effect of HIV on adipose tissue (AT). We found an increase in CD4+ cells and detectable SHIV-RNA in AT during acute SHIV infection. SHIV-RNA+ cells were rare, suggesting that AT is unlikely to be a major source of productively infected cells in SHIV infection.
Byrnes, SJ;Busman-Sahay, K;Angelovich, TA;Younger, S;Taylor-Brill, S;Nekorchuk, M;Bondoc, S;Dannay, R;Terry, M;Cochrane, CR;Jenkins, TA;Roche, M;Deleage, C;Bosinger, SE;Paiardini, M;Brew, BJ;Estes, JD;Churchill, MJ;
PMID: 36989320 | DOI: 10.1371/journal.ppat.1011290
HIV-associated neurocognitive disorders (HAND) affect ~40% of virally suppressed people with HIV (PWH), however, the precise viral dependent and independent changes to the brain are unclear. Here we characterized the CNS reservoir and immune environment of SIV-infected (SIV+) rhesus macaques during acute (n = 4), chronic (n = 12) or ART-suppressed SIV infection (n = 11). Multiplex immunofluorescence for markers of SIV infection (vRNA/vDNA) and immune activation was performed on frontal cortex and matched colon tissue. SIV+ animals contained detectable viral DNA+ cells that were not reduced in the frontal cortex or the gut by ART, supporting the presence of a stable viral reservoir in these compartments. SIV+ animals had impaired blood brain barrier (BBB) integrity and heightened levels of astrocytes or myeloid cells expressing antiviral, anti-inflammatory or oxidative stress markers which were not abrogated by ART. Neuroinflammation and BBB dysfunction correlated with measures of viremia and immune activation in the gut. Furthermore, SIV-uninfected animals with experimentally induced gut damage and colitis showed a similar immune activation profile in the frontal cortex to those of SIV-infected animals, supporting the role of chronic gut damage as an independent source of neuroinflammation. Together, these findings implicate gut-associated immune activation/damage as a significant contributor to neuroinflammation in ART-suppressed HIV/SIV infection which may drive HAND pathogenesis.
