ABSTRACT
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), seriously threatens human life and health. The correct folding and polymerization of the receptor-binding domain (RBD) protein of coronavirus in Escherichia coli may reduce the cost of SARS-CoV-2 vaccines. In this study, we constructed this nanopore by using the principle of ClyA porin polymerization triggered by the cell membrane. We used surfactants to "pick" the ClyA-RBD nanopore from the bacterial outer membrane. More importantly, the polymerized RBD displayed on the ClyA-RBD polymerized porin (RBD-PP) already displays some correct spatial conformational epitopes that can induce neutralizing antibodies. The nanostructures of RBD-PP can target lymph nodes and promote antigen uptake and processing by dendritic cells, thereby effectively eliciting the production of anti-SARS-CoV-2 neutralizing antibodies, systemic cellular immune responses, and memory T cells. We applied this PP-based vaccine platform to fabricate an RBD-based subunit vaccine against SARS-CoV-2, which will provide a foundation for the development of inexpensive coronavirus vaccines. The development of a novel vaccine delivery system is an important part of innovative drug research. This novel PP-based vaccine platform is likely to have additional applications, including other viral vaccines, bacterial vaccines, tumor vaccines, drug delivery, and disease diagnosis.
Subject(s)
COVID-19 Vaccines , COVID-19 , Antibodies, Neutralizing , Antibodies, Viral/metabolism , COVID-19/prevention & control , Humans , Polymerization , Porins , SARS-CoV-2 , Spike Glycoprotein, CoronavirusABSTRACT
The inappropriate use of antibiotics is a severe public health problem worldwide, contributing to the emergence of multidrug-resistant (MDR) bacteria. To explore the possible impacts of the inappropriate use of antibiotics on the immune system, we use Klebsiella pneumoniae (K. pneumoniae) infection as an example and show that imipenem increases the mortality of mice infected by MDR K. pneumoniae. Further studies demonstrate that imipenem enhances the secretion of outer membrane vesicles (OMVs) with significantly elevated presentation of GroEL, which promotes the phagocytosis of OMVs by macrophages that depends on the interaction between GroEL and its receptor, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1). OMVs cause the pyroptosis of macrophages and the release of proinflammatory cytokines, which contribute to exacerbated inflammatory responses. We propose that the inappropriate use of antibiotics in the cases of infection by MDR bacteria such as K. pneumoniae might cause damaging inflammatory responses, which underlines the pernicious effects of inappropriate use of antibiotics.
Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Multiple, Bacterial/drug effects , Extracellular Vesicles/metabolism , Klebsiella pneumoniae/pathogenicity , Pyroptosis , Animals , Bacterial Proteins/metabolism , Carbapenems/pharmacology , Chaperonin 60/metabolism , Cytokines/metabolism , Inflammation/metabolism , Inflammation/pathology , Inflammation/veterinary , Klebsiella Infections/mortality , Klebsiella Infections/pathology , Klebsiella Infections/veterinary , Klebsiella pneumoniae/metabolism , Macrophages/cytology , Macrophages/immunology , Macrophages/metabolism , Mice , Mice, Inbred C57BL , Phagocytosis , RNA Interference , RNA, Small Interfering/metabolism , Scavenger Receptors, Class E/antagonists & inhibitors , Scavenger Receptors, Class E/genetics , Scavenger Receptors, Class E/metabolism , Survival RateABSTRACT
T cell activation-induced cell death (AICD) during tumor pathogenesis is a tumor immune escape process dependent on dendritic cells (DCs). Proper immune-modulatory therapies effectively inhibit tumor-specific CD8+ T cell exhaustion and enhance antitumor immune responses. Here, high-pressure homogenization is utilized to drive immunomodulator IL10-modified bacteria to extrude through the gap and self-assemble into bacterial biomimetic vesicles exposing IL10 (IL10-BBVs) on the surface with high efficiency. IL10-BBVs efficiently target DCs in tumor-draining lymph nodes and thus increase the interaction between IL10 on BBVs and IL10R on DCs to suppress AICD and mitigate CD8+ T cell exhaustion specific to tumor antigens. Two subcutaneous peripheral injections of IL10-BBVs 1 week apart in tumor-bearing mice effectively increase systemic and intratumoral proportions of CD8+ T cells to suppress tumor growth and metastasis. Tumor-specific antigen E7 is enclosed into the periplasm of IL10-BBVs (IL10-E7-BBVs) to realize concurrent actions of the immunomodulator IL10 and the tumor antigen human papillomavirus (HPV) 16E7 in lymph nodes, further enhancing the antitumor effects mediated by CD8+ T cells. The development of this modified BBV delivery platform will expand the application of bacterial membranes and provide novel immunotherapeutic strategies for tumor treatment.
Subject(s)
BiomimeticsABSTRACT
The disease caused by SARS-CoV-2 infection threatens human health. In this study, we used high-pressure homogenization technology not only to efficiently drive the bacterial membrane to produce artificial vesicles but also to force the fusion protein ClyA-receptor binding domain (RBD) to pass through gaps in the bacterial membrane to increase the contact between ClyA-RBD and the membrane. Therefore, the load of ClyA-RBD on the membrane is substantially increased. Using this technology, we constructed a "ring-like" bacterial biomimetic vesicle (BBV) loaded with polymerized RBD (RBD-BBV). RBD-BBVs injected subcutaneously can accumulate in lymph nodes, promote antigen uptake and processing, and elicit SARS-CoV-2-specific humoral and cellular immune responses in mice. In conclusion, we evaluated the potential of this novel bacterial vesicle as a vaccine delivery system and provided a new idea for the development of SARS-CoV-2 vaccines.
Subject(s)
COVID-19 , Spike Glycoprotein, Coronavirus , Animals , COVID-19 Vaccines , Humans , Mice , Protein Binding , SARS-CoV-2ABSTRACT
Drug resistance of Klebsiella pneumoniae severely threatens human health. Overcoming the mechanisms of K. pneumoniae resistance to develop novel vaccines against drug-resistant K. pneumoniae is highly desired. Here, we report a technology platform that uses high pressure to drive drug-resistant K. pneumoniae to pass through a gap, inducing the formation of stable artificial bacterial biomimetic vesicles (BBVs). These BBVs had little to no bacterial intracellular protein or nucleic acid and had high yields. BBVs were efficiently taken up by dendritic cells to stimulate their maturation. BBVs as K. pneumoniae vaccines had the dual functions of inducing bacteria-specific humoral and cellular immune responses to increase animals' survival rate and reduce pulmonary inflammation and bacterial loads. We believe that BBVs are new-generation technology for bacterial vesicle preparation. Establishment of this BBV vaccine platform can maximally expand preparation technology for vaccines against drug-resistant K. pneumoniae.
