RESUMO
Cellular uptake of antigens (Ags) by antigen-presenting cells (APCs) is vital for effective functioning of the immune system. Intramuscular or subcutaneous administration of vaccine Ags alone is not sufficient to elicit optimal immune responses. Thus, adjuvants are required to induce strong immunogenicity. Here, we developed nanoparticulate adjuvants that assemble into a bilayer spherical polymersome (PSome) to promote the cellular uptake of Ags by APCs. PSomes were synthesized by using a biodegradable and biocompatible block copolymer methoxy-poly(ethylene glycol)-b-poly(d,l-lactide) to encapsulate both hydrophilic and lipophilic biomacromolecules, such as ovalbumin (OVA) as a model Ag and monophosphoryl lipid A (MPLA) as an immunostimulant. After co-encapsulation of OVA and MPLA, the PSome synthetic vehicle exhibited the sustained release of OVA in cell environments and allowed efficient delivery of cargos into APCs. The administration of PSomes loaded with OVA and MPLA induced the production of interleukin-6 and tumor necrosis factor-alpha cytokines by macrophage activation in vitro and elicited effective Ag-specific antibody responses in vivo. These findings indicate that the nano-sized PSome may serve as a potent adjuvant for vaccine delivery systems to modulate enhanced immune responses.
Assuntos
Células Apresentadoras de Antígenos/química , Lipídeo A/análogos & derivados , Nanopartículas/química , Ovalbumina/química , Polímeros/química , Animais , Reações Antígeno-Anticorpo , Células Apresentadoras de Antígenos/imunologia , Feminino , Lipídeo A/química , Lipídeo A/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Estrutura Molecular , Ovalbumina/imunologia , Tamanho da Partícula , Polímeros/síntese química , Células RAW 264.7 , Propriedades de SuperfícieRESUMO
Powerful adjuvants to augment vaccine efficacy with a less immunogenic vaccine system are in great demand. In this study, a novel squalene-based cationic poly(amino acid) adjuvant (CASq) that elicits both cellular (Th1) and humoral (Th2) immune responses is developed. CASq is demonstrated to promote cellular uptake of viral antigen and stimulate macrophages, leading to active production of interleukin-12. Furthermore, co-administration of inactivated pdm H1N1 vaccine with CASq significantly increases the generation of antigen-specific antibodies and T cell immune responses in mice, as well as resulting in complete prevention of disease symptoms and protection against lethal infection.