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Project description:Innate pattern recognition receptor agonists, including Toll-like receptors (TLRs), alter the tumor microenvironment and prime adaptive antitumor immunity. However, TLR agonists present toxicities associated with widespread immune activation after systemic administration. To design a TLR-based therapeutic suitable for systemic delivery and capable of safely eliciting tumor-targeted responses, we developed immune-stimulating antibody conjugates (ISACs) comprising a TLR7/8 dual agonist conjugated to tumor-targeting antibodies. Systemically administered human epidermal growth factor receptor 2 (HER2)-targeted ISACs were well tolerated and triggered a localized immune response in the tumor microenvironment that resulted in tumor clearance and immunological memory. Mechanistically, ISACs required tumor antigen recognition, Fcγ-receptor-dependent phagocytosis and TLR-mediated activation to drive tumor killing by myeloid cells and subsequent T-cell-mediated antitumor immunity. ISAC-mediated immunological memory was not limited to the HER2 ISAC target antigen since ISAC-treated mice were protected from rechallenge with the HER2- parental tumor. These results provide a strong rationale for the clinical development of ISACs.
| S-EPMC9012298 | biostudies-literature
Project description:Innate pattern recognition receptors, including toll-like receptors (TLRs), can alter the tumor microenvironment and prime adaptive anti-tumor immunity. However, TLR agonists have not been well-tolerated due to toxicities associated with widespread immune activation following systemic administration. To design a therapeutic that is suitable for systemic delivery and capable of eliciting a tumor-targeted response, we developed a novel class of immune-stimulating antibody conjugates (ISACs) comprising a TLR7/8 agonist conjugated to tumor-targeting antibodies. Systemically administered anti-HER2 ISACs were well-tolerated in vivo and elicited robust activation of intratumoral myeloid cells, resulting in tumor clearance and subsequent immunological memory. In vitro potency and in vivo efficacy required tandem activity driven by intact Fc functionality and TLR agonism to enable phagocytosis and T cell-mediated anti-tumor immunity. ISAC-mediated immunological memory was not limited to HER2, as ISAC-treated mice were protected from rechallenge with a HER2-negative tumor. These results provide strong rationale for the clinical development of ISACs and show that synergy between FcgR and TLR7/8 signaling contributes to the mechanism of ISAC-mediated anti-tumor immunity.
2020-12-03 | GSE157869 | GEO
Project description:Innate pattern recognition receptors, including toll-like receptors (TLRs), can alter the tumor microenvironment and prime adaptive anti-tumor immunity. However, TLR agonists have not been well-tolerated due to toxicities associated with widespreadimmune activation following systemic administration. To design a therapeutic that is suitable for systemic delivery and capable of eliciting a tumor-targeted response, we developed a novel class of immune-stimulating antibody conjugates (ISACs) comprising a TLR7/8 agonist conjugated to tumor-targeting antibodies. Systemically administered anti-HER2 ISACs were well-tolerated in vivo and elicited robust activation of intratumoral myeloid cells, resulting in tumor clearance and subsequent immunological memory. In vitro potency and in vivo efficacy required tandem activity driven by intact Fc functionality and TLR agonism to enable phagocytosis and T cell-mediated anti-tumor immunity. ISAC-mediated immunological memory was not limited to HER2, as ISAC-treated mice were protected from rechallenge with a HER2-negative tumor. These results provide strong rationale for the clinical development of ISACs and show that synergy between FcgR and TLR7/8 signaling contributes to the mechanism of ISAC-mediated anti-tumor immunity.
2020-12-03 | GSE157848 | GEO
Project description:Immune-stimulating antibody conjugates elicit robust myeloid activation and durable anti-tumor immunity
| PRJNA663153 | ENA
Project description:Immune-stimulating antibody conjugates elicit robust myeloid activation and durable anti-tumor immunity I
| PRJNA662959 | ENA
Project description:Immune-stimulating antibody conjugates elicit robust myeloid activation and durable anti-tumor immunity II
| PRJNA663155 | ENA
Project description:The SARS-CoV-2 Delta variant is currently responsible for most infections worldwide, including among fully vaccinated individuals. Although these latter infections are associated with milder COVID-19 disease relative to unvaccinated subjects, the specificity and durability of antibody responses elicited by Delta breakthrough cases remain unknown. Here, we demonstrate that breakthrough infections induce serum binding and neutralizing antibody responses that are markedly more potent, durable and resilient to spike mutations observed in variants of concern than those observed in subjects who were infected only or received only two doses of COVID-19 vaccine. However, wee show that Delta breakthrough cases, subjects who were vaccinated after SARS-CoV-2 infection and individuals vaccinated three times (without infection) have serum neutralizing activity of comparable magnitude and breadth indicate that multiple types of exposure or increased number of exposures to SARS-CoV-2 antigen(s) enhance spike-specific antibody responses. Neutralization of the genetically divergent SARS-CoV, however, was moderate with all four cohorts examined, except after four exposures to the SARS-CoV-2 spike, underscoring the importance of developing vaccines eliciting broad sarbecovirus immunity for pandemic preparedness.
| S-EPMC8687475 | biostudies-literature
Project description:Conventional foot-and-mouth disease (FMD) vaccines exhibit several limitations, such as the slow induction of antibodies, short-term persistence of antibody titers, as well as low vaccine efficacy and safety, in pigs. Despite the importance of cellular immune response in host defense at the early stages of foot-and-mouth disease virus (FMDV) infection, most FMD vaccines focus on humoral immune response. Antibody response alone is insufficient to provide full protection against FMDV infection; cellular immunity is also required. Therefore, it is necessary to design a strategy for developing a novel FMD vaccine that induces a more potent, cellular immune response and a long-lasting humoral immune response that is also safe. Previously, we demonstrated the potential of various pattern recognition receptor (PRR) ligands and cytokines as adjuvants for the FMD vaccine. Based on these results, we investigated PRR ligands and cytokines adjuvant-mediated memory response in mice. Additionally, we also investigated cellular immune response in peripheral blood mononuclear cells (PBMCs) isolated from cattle and pigs. We further evaluated target-specific adjuvants, including Mincle, STING, TLR-7/8, and Dectin-1/2 ligand, for their role in generating ligand-mediated and long-lasting memory responses in cattle and pigs. The combination of Mincle and STING-stimulating ligands, such as trehalose-6, 6'dibehenate (TDB), and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), induced high levels of antigen-specific and virus-neutralizing antibody titers at the early stages of vaccination and maintained a long-lasting immune memory response in pigs. These findings are expected to provide important clues for the development of a robust FMD vaccine that stimulates both cellular and humoral immune responses, which would elicit a long-lasting, effective immune response, and address the limitations seen in the current FMD vaccine.
| S-EPMC6828931 | biostudies-literature
Project description:Although infections among vaccinated individuals lead to milder COVID-19 symptoms relative to those in unvaccinated subjects, the specificity and durability of antibody responses elicited by breakthrough cases remain unknown. Here, we demonstrate that breakthrough infections induce serum-binding and -neutralizing antibody responses that are markedly more potent, durable, and resilient to spike mutations observed in variants than those in subjects who received only 2 doses of vaccine. However, we show that breakthrough cases, subjects who were vaccinated after infection, and individuals vaccinated three times have serum-neutralizing activity of comparable magnitude and breadth, indicating that an increased number of exposures to SARS-CoV-2 antigen(s) enhance the quality of antibody responses. Neutralization of SARS-CoV was moderate, however, underscoring the importance of developing vaccines eliciting broad sarbecovirus immunity for pandemic preparedness.
| S-EPMC8769922 | biostudies-literature
Project description:Nitazoxanide (Alinia(®), NTZ) and tizoxanide (TIZ), its active circulating metabolite, belong to a class of agents known as thiazolides (TZD) endowed with broad anti-infective activities. TIZ and RM-4848, the active metabolite of RM-5038, were shown to stimulate innate immunity in vitro. Because natural resistance to HIV-1 infection in HIV-exposed seronegative (HESN) individuals is suggested to be associated with strong innate immune responses, we verified whether TIZ and RM-4848 could reduce the in vitro infectiousness of HIV-1. Peripheral blood mononuclear cells (PBMCs) from 20 healthy donors were infected in vitro with HIV-1BaL in the presence/absence of TIZ or RM4848. HIV-1 p24 were measured at different timepoints. The immunomodulatory abilities of TZD were evaluated by the expression of type I IFN pathway genes and the production of cytokines and chemokines. TZD drastically inhibited in vitro HIV-1 replication (>87%). This was associated with the activation of innate immune responses and with the up-regulation of several interferon-stimulated genes (ISGs), including those involved in cholesterol pathway, particularly the cholesterol-25 hydroxylase (CH25H). TZD inhibition of HIV-1 replication in vitro could be due to their ability to stimulate potent and multifaceted antiviral immune responses. These data warrant the exploration of TZD as preventive/therapeutic agent in HIV infection.
| S-EPMC4890011 | biostudies-other