Subunit proteins provide a safe source of antigens for vaccine development especially for intracellular infections which require the induction of strong cellular immune responses. However, those antigens are often limited by their low immunogenicity. In order to achieve effective immune responses, they should be encapsulated into a stable antigen delivery system combined with an appropriate adjuvant. As such cationic liposomes provide an efficient platform for antigen delivery. In the present study, we describe a liposomal vaccine platform for co-delivery of antigens and adjuvants able to elicit strong antigen-specific adaptive immune responses. Liposomes are composed of the cationic lipid dimethyl dioctadecylammonium bromide (DDAB), cholesterol (CHOL) and oleic acid (OA). Physicochemical characterization of the formulations showed that their size was in the range of ∼250 nm with a positive zeta potential which was affected in some cases by the enviromental pH facilitating endosomal escape of potential vaccine cargo. In vitro, liposomes were effectively taken up by bone marrow dendritic cells (BMDCs) and when encapsulated IMQ they promoted BMDCs maturation and activation. Upon in vivo intramuscular administration, liposomes' active drainage to lymph nodes was mediated by DCs, B cells and macrophages. Thus, mice immunization with liposomes having encapsulated LiChimera, a previously characterized anti-leishmanial antigen, and IMQ elicited infiltration of CD11b^low DCs populations in draining LNs followed by increased antigen-specific IgG, IgG2a and IgG1 levels production as well as indcution of antigen-specific CD4⁺ and CD8⁺ T cells. Collectively, the present work provides a proof-of-concept that cationic liposomes composed of DDAB, CHOL and OA adjuvanted with IMQ provide an efficient delivery platform for protein antigens able to induce strong adaptive immune responses via DCs targeting and induction of maturation.

2022-03-01·Journal of Controlled Release1区 · 医学

Intravenous liposomal vaccine enhances CTL generation, but not until antigen presentation

1区 · 医学

Article

作者: Harashima, Hideyoshi ; Nakamura, Takashi ; Haloho, Sion Elisabeth Elfainatur

Adjuvant loaded nanoparticles are a potent strategy for developing effective combined cancer immunotherapies. A polyinosinic-polycytidylic acid (poly I:C) is a ligand for toll-like receptor 3 and a promising cancer adjuvant. However, regarding intravenous administration, the potential for and the mechanism of poly I:C loaded nanoparticles as a cancer vaccine are largely unknown. We investigated the effects of using a combination of poly I:C and an antigen loaded liposome for cancer immunotherapy and a key process for achieving effective antitumor immunity of the liposome system under conditions of intravenous vaccination. A poly I:C and ovalbumin (OVA) loaded octaarginine (R8) modified liposome (PoIC/OVA-R8L) drastically inhibited the systemic cytokine production derived from the poly I:C intravenous injection. Treatment with PoIC/OVA-R8L improved the immune status in B16-OVA tumors to an inflamed immune status and induced a significant combined antitumor effect with the anti-programmed cell death 1 ligand (PD-L1). In a mechanistic analysis compared with a high dose of the free form of poly I:C, interestingly, local cytokine production, maturation of antigen presenting cells and antigen presentation were comparable. Conversely, significant differences were identified in the processes after OVA-specific CTL generation. Collectively, our findings have implications for the development of intravenous liposomal vaccines.

2021-03-23·ACS Nano1区 · 材料科学

A Potent Cancer Vaccine Adjuvant System for Particleization of Short, Synthetic CD8⁺ T Cell Epitopes

1区 · 材料科学

Article

作者: Morgan, M. Thomas ; Zhou, Shiqi ; Seffouh, Amal ; Lovell, Jonathan F. ; Mabrouk, Moustafa T. ; Abrams, Scott I. ; He, Xuedan ; Huang, Wei-Chiao ; Ortega, Joaquin

Short major histocompatibility complex (MHC) class I (MHC-I)-restricted peptides contain the minimal biochemical information to induce antigen (Ag)-specific CD8⁺ cytotoxic T cell responses but are generally ineffective in doing so. To address this, we developed a cobalt-porphyrin (CoPoP) liposome vaccine adjuvant system that induces rapid particleization of conventional, short synthetic MHC-I epitopes, leading to strong cellular immune responses at nanogram dosing. Along with CoPoP (to induce particle formation of peptides), synthetic monophosphoryl lipid A (PHAD) and QS-21 immunostimulatory molecules were included in the liposome bilayer to generate the "CPQ" adjuvant system. In mice, immunization with a short MHC-I-restricted peptide, derived from glycoprotein 70 (gp70), admixed with CPQ safely generated functional, Ag-specific CD8⁺ T cells, resulting in the rejection of multiple tumor cell lines, with durable immunity. When cobalt was omitted, the otherwise identical peptide and adjuvant components did not result in peptide binding and were incapable of inducing immune responses, demonstrating the importance of stable particle formation. Immunization with the liposomal vaccine was well-tolerated and could control local and metastatic disease in a therapeutic setting. Mechanistic studies showed that particle-based peptides were better taken up by antigen-presenting cells, where they were putatively released within endosomes and phagosomes for display on MHC-I surfaces. On the basis of the potency of the approach, the platform was demonstrated as a tool for in vivo epitope screening of peptide microlibraries comprising a hundred peptides.

100 项与 HBV liposomal vaccine(SciGen/NasVax) 相关的药物交易

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