Photoinduced Photosensitizer-Antibody Conjugates Kill HIV Env-Expressing Cells, Also Inactivating HIV.
Ontology highlight
ABSTRACT:
SUBMITTER: Sadraeian M
PROVIDER: S-EPMC8246456 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Different therapeutic strategies have been investigated to target and eliminate HIV-1-infected cells by using armed antibodies specific to viral proteins, with varying degrees of success. Herein, we propose a new strategy by combining photodynamic therapy (PDT) with HIV Env-targeted immunotherapy, and refer to it as HIV photoimmunotherapy (PIT). A human anti-gp41 antibody (7B2) was conjugated to two photosensitizers (PSs) with different charges through different linking strategies; "Click" conjugation by using an azide-bearing porphyrin attached via a disulfide bridge linker with a drug-to-antibody ratio (DAR) of exactly 4, and "Lysine" conjugation by using phthalocyanine IRDye 700DX dye with average DARs of 2.1, 3.0 and 4.4. These photo-immunoconjugates (PICs) were compared via biochemical and immunological characterizations regarding the dosimetry, solubility, and cell targeting. Photo-induced cytotoxicity of the PICs were compared using assays for apoptosis, reactive oxygen species (ROS), photo-cytotoxicity, and confocal microscopy. Targeted phototoxicity seems to be primarily dependent on the binding of PS-antibody to the HIV antigen on the cell membrane, whilst being independent of the PS type. This is the first report of the application of PIT for HIV immunotherapy by killing HIV Env-expressing cells.
| S-EPMC7730620 | biostudies-literature
Project description:The SARS-CoV-2 pandemic has highlighted the weaknesses of relying on single-use mask and respirator personal protective equipment (PPE) and the global supply chain that supports this market. There have been no major innovations in filter technology for PPE in the past two decades. Non-woven textiles used for filtering PPE are single-use products in the healthcare environment; use and protection is focused on preventing infection from airborne or aerosolized pathogens such as Influenza A virus or SARS-CoV-2. Recently, C-H bond activation under mild and controllable conditions was reported for crosslinking commodity aliphatic polymers such as polyethylene and polypropylene. Significantly, these are the same types of polymers used in PPE filtration systems. In this report, we take advantage of this C-H insertion method to covalently attach a photosensitizing zinc-porphyrin to the surface of a melt-blow non-woven textile filter material. With the photosensitizer covalently attached to the surface of the textile, illumination with visible light was expected to produce oxidizing 1O2/ROS at the surface of the material that would result in pathogen inactivation. The filter was tested for its ability to inactivate Influenza A virus, an enveloped RNA virus similar to SARS-CoV-2, over a period of four hours with illumination of high intensity visible light. The photosensitizer-functionalized polypropylene filter inactivated our model virus by 99.99% in comparison to a control.
| S-EPMC8463589 | biostudies-literature
Project description:CD4 T follicular helper cells (Tfh) are essential for establishing serological memory and have distinct helper attributes that impact both the quantity and quality of the antibody response. Therefore, gaining insights into Tfh subsets promoting antibody persistence and functional capacity is crucial for vaccine design. We investigated the potential of inducing a mixed Tfh1/17 response to enhance HIV-1 Envelope (Env) antibodies to a DNA-prime/protein boost platform, utilizing rhesus macaques as our experimental model. Following immunization with Clade C gp140 protein formulated with cationic liposome-based formulation (CAF01), we successfully generated germinal center (GC) Tfh1/17 cells, in contrast to the predominance of GC Tfh1 cells induced with gp140 formulated in monophosphoryl lipid A+QS-21 (MPLA). Analysis of lymph nodes, employing proteomic and transcriptional approaches, demonstrated robust induction of GC responses across vaccine platforms with distinct qualitative and quantitative effects elicited by MPLA versus CAF01. While the induction of GC Tfh1 cells with MPLA and GC Tfh1/17 cells with CAF01 resulted in comparable peak HIV-Env antibody levels, there was a notable difference in antibody persistence. The MPLA group demonstrated significantly greater antibody persistence at week 8 and up to 30 weeks after final immunization compared to CAF01. Inducing GC Tfh1 cells with MPLA furthermore enhanced tier 1 neutralization titers, antibody functions, and Env-specific IgG in the rectal mucosa. Notably, IFNγ+ Env-specific Tfh responses, both in blood and lymph nodes, were higher with MPLA and correlated with Env antibody persistence. These findings suggest that vaccine platforms maximizing GC Tfh1 induction may confer protective immunity against HIV.
2023-06-16 | GSE234813 | GEO
Project description:A strategy has been established for the synthesis of a family of bifunctional HIV-1 inhibitor covalent conjugates with the potential to bind simultaneously to both the gp120 and gp41 subunits of the HIV-1 envelope glycoprotein trimeric complex (Env). One component of the conjugates is derived from BNM-III-170, a small-molecule CD4 mimic that binds to gp120. The second component, comprised of the peptide DKWASLWNW ("Trp3"), was derived from the N-terminus of the HIV-1 gp41 Membrane Proximal External Region (MPER) and found previously to bind to the gp41 subunit of Env. The resulting bifunctional conjugates were shown to inhibit virus cell infection with low micromolar potency and to induce lysis of the HIV-1 virion. Crucially, virolysis was found to be dependent on the covalent linkage of the BNM-III-170 and Trp3 domains, as coadministration of a mixture of the un-cross-linked components proved to be nonlytic. However, a significant magnitude of lytic activity was observed in Env-negative and other control pseudoviruses, suggesting parallel mechanisms of action of the conjugates involving Env interaction and direct membrane disruption. Computational modeling suggested strong membrane-binding activity of BNM-III-170, which may underly the nonspecific virolytic effects of the conjugates. To investigate the scope of the membrane effect, cell-based cytotoxicity and membrane permeability assays were performed employing flow cytometry. Here, we observed a dose-dependent and specific cytotoxic effect on HIV-1 Env-expressing cells by the small-molecule bifunctional inhibitor. Most importantly, Env-negative cells were not susceptible to the cytotoxic effect upon exposure to this construct at concentrations where cell-killing effects were observed for Env-positive cells. Computational structural modeling supports a mechanism in which the bifunctional inhibitors bind to the gp120 and gp41 subunits in tandem in open-state Env trimers and induce relative motion of the gp120 subunits consistent with models of Env inactivation. This observation supports the idea that the cell-killing effect of the small-molecule bifunctional inhibitor is due to specific Env conformational triggering. This work lays important groundwork to advance a small-molecule bifunctional inhibitor approach for eliminating Env-expressing infected cells and the eradication of HIV-1.
| S-EPMC8218882 | biostudies-literature
Project description:Rationale: Antiretroviral therapy can effectively suppress HIV-1 replication in the peripheral blood to an undetectable level. However, elimination of the latent virus in reservoirs remains a challenge and is a major obstacle in the treatment of HIV-1-infected patients. Exosomes exhibit huge promise as an endogenous drug delivery nanosystem for delivering drugs to solid tissues given their unique properties, including low immunogenicity, innate stability, high delivery efficiency, and most importantly the ability to penetrate solid tissues due to their lipophilic properties. Methods: We engineered and expressed the scFv of a high affinity HIV-1-specific monoclonal antibody, 10E8, on the exosomal surface (10E8scFv-exos). Subsequently, the 10E8scFv-exos were loaded with curcumin (Cur), a chemical that kills HIV-1-infected cells, or miR-143, an apoptosis-inducing miRNA. We tested the ability of 10E8scFv-exos to deliver cargo to Env+ target cells and tissues, as well as their ability to suppress HIV-1 infection. Results: 10E8scFv-exos efficiently targeted CHO cells expressing a trimeric gp140 on their surface (Env+ cells) in vitro, as demonstrated by confocal imaging and flow cytometry. 10E8scFv-exos loaded with Cur or miR-143 showed specific killing of Env+ cells. In addition, 10E8scFv-exos loaded with Cur or miR-143 could suppress p24 expression in an HIV-1 latency cell line ACH2 and in PBMCs from an ART-treated HIV-1-infected patient. In an NCG mouse model grafted with tumorigenic Env+ CHO cells and which had developed solid tissue tumors, intravenously injected 10E8scFv-exos targeted the Env-expressing tissues and delivered Cur to induce a strong suppression of the Env+ tumor growth with low toxicity. Conclusion: In principle, engineered exosomes can deliver anti-HIV agents to solid tissues by specifically targeting cells expressing viral envelop proteins and inducing cell killing, suggesting that such an approach could be developed for eradicating virus-infected cells in tissue reservoirs.
| S-EPMC6735399 | biostudies-literature
Project description:Peptide triazole (PT) antagonists interact with gp120 subunits of HIV-1 Env trimers to block host cell receptor interactions, trigger gp120 shedding, irreversibly inactivate virus and inhibit infection. Despite these enticing functions, understanding the structural mechanism of PT-Env trimer encounter has been limited. In this work, we combined competition interaction analysis and computational simulation to demonstrate PT binding to the recombinant soluble trimer, BG505 SOSIP.664, a stable variant that resembles native virus spikes in binding to CD4 receptor as well as known conformationally-dependent Env antibodies. Binding specificity and computational modeling fit with encounter through complementary PT pharmacophore Ile-triazolePro-Trp interaction with a 2-subsite cavity in the Env gp120 subunit of SOSIP trimer similar to that in monomeric gp120. These findings argue that PTs are able to recognize and bind a closed prefusion state of Env trimer upon HIV-1 encounter. The results provide a structural model of how PTs exert their function on virion trimeric spike protein and a platform to inform future antagonist design. Proteins 2017; 85:843-851. © 2016 Wiley Periodicals, Inc.
| S-EPMC5389922 | biostudies-literature
Project description:Photodynamic therapy (PDT) is an approach that kills (cancer) cells by the local production of toxic reactive oxygen species upon the local illumination of a photosensitizer (PS). The specificity of PDT has been further enhanced by the development of a new water-soluble PS and by the specific delivery of PS via conjugation to tumor-targeting antibodies. To improve tissue penetration and shorten photosensitivity, we have recently introduced nanobodies, also known as VHH (variable domains from the heavy chain of llama heavy chain antibodies), for targeted PDT of cancer cells overexpressing the epidermal growth factor receptor (EGFR). Overexpression and activation of another cancer-related receptor, the hepatocyte growth factor receptor (HGFR, c-Met or Met) is also involved in the progression and metastasis of a large variety of malignancies. In this study we evaluate whether anti-Met VHHs conjugated to PS can also serve as a biopharmaceutical for targeted PDT. VHHs targeting the SEMA (semaphorin-like) subdomain of Met were provided with a C-terminal tag that allowed both straightforward purification from yeast supernatant and directional conjugation to the PS IRDye700DX using maleimide chemistry. The generated anti-Met VHH-PS showed nanomolar binding affinity and, upon illumination, specifically killed MKN45 cells with nanomolar potency. This study shows that Met can also serve as a membrane target for targeted PDT.
| S-EPMC6640711 | biostudies-literature
Project description:Elicitation of broadly neutralizing Ab (bNAb) responses to the conserved elements of the HIV-1 envelope glycoproteins (Env), including the primary receptor CD4 binding site (CD4bs), is a major focus of vaccine development yet to be accomplished. However, a large number of CD4bs-directed bNAbs have been isolated from HIV-1-infected individuals. Comparison of the routes of binding used by the CD4bs-directed bNAbs from patients and the vaccine-elicited CD4bs-directed mAbs indicates that the latter fail to neutralize primary virus isolates because they approach the Env spike with a vertical angle and contact the specific surface residues occluded in the native spike, including the bridging sheet on gp120. To preferentially expose the CD4bs and direct the immune response away from the bridging sheet, resulting in an altered angle of approach, we engineered an immunogen consisting of gp120 core in complex with the prototypic CD4-induced Ab, 17b. This mAb directly contacts the bridging sheet but not the CD4bs. The complex was further stabilized by chemical crosslinking to prevent dissociation. Rabbits immunized with the crosslinked complex displayed earlier affinity maturation, achieving tier 1 virus neutralization compared with animals immunized with gp120 core alone. Immunization with the crosslinked complex induced transient Ab responses with binding specificity similar to the CD4bs-directed bNAbs. mAbs derived from complex-immunized rabbits displayed footprints on gp120 more distal from the bridging sheet as compared with previous vaccine-elicited CD4bs Abs, indicating that Env-Ab complexes effectively dampen immune responses to undesired immunodominant bridging sheet determinants.
| S-EPMC5117957 | biostudies-literature
Project description:Engineered ectodomain trimer immunogens based on BG505 envelope glycoprotein are widely utilized as components of HIV vaccine development platforms. In this study, we used rhesus macaques to evaluate the immunogenicity of several stabilized BG505 SOSIP constructs both as free trimers and presented on a nanoparticle. We applied a cryoEM-based method for high-resolution mapping of polyclonal antibody responses elicited in immunized animals (cryoEMPEM). Mutational analysis coupled with neutralization assays were used to probe the neutralization potential at each epitope. We demonstrate that cryoEMPEM data can be used for rapid, high-resolution analysis of polyclonal antibody responses without the need for monoclonal antibody isolation. This approach allowed to resolve structurally distinct classes of antibodies that bind overlapping sites. In addition to comprehensive mapping of commonly targeted neutralizing and non-neutralizing epitopes in BG505 SOSIP immunogens, our analysis revealed that epitopes comprising engineered stabilizing mutations and of partially occupied glycosylation sites can be immunogenic.
| S-EPMC8355326 | biostudies-literature
Project description:To minimize immune responses against infected cells, HIV-1 limits the surface expression of its envelope glycoprotein (Env). Here, we demonstrate that this mechanism is specific for the Env conformation and affects the efficiency of antibody-dependent cellular cytotoxicity (ADCC). Using flow cytometry and confocal microscopy, we show that broadly neutralizing antibodies (bNAbs) targeting the "closed" conformation of Env induce its internalization from the surface. In contrast, non-neutralizing antibodies (nNAbs) are displayed on the cell surface for prolonged period of times. The bNAb-induced Env internalization can be decreased by blocking dynamin function, which translates into higher susceptibilities of infected cells to ADCC. Our results suggest that antibody-mediated Env internalization is a mechanism used by HIV-1 to evade immune responses against the "closed" conformation of Env expressed on HIV-1-infected cells.IMPORTANCE HIV-1 has evolved to acquire several strategies to limit the exposure of its envelope glycoproteins (Env) on the surface of infected cells. In this study, we show that antibody-induced Env internalization is conformation specific and reduces the susceptibility of infected cells to antibody-dependent cellular cytotoxicity (ADCC). Thus, a better understanding of this mechanism might help develop antibodies with improved capacities to mediate ADCC.
| S-EPMC6532100 | biostudies-literature