Exosomes are a valuable biomaterial for the development of novel nanocarriers as functionally advanced drug delivery systems. To control and modify the performance of exosomal nanocarriers, we developed hybrid exosomes by fusing their membranes with liposomes using the freeze–thaw method. Exosomes embedded with a specific membrane protein isolated from genetically modified cells were fused with various liposomes, confirming that membrane engineering methods can be combined with genetic modification techniques. Cellular uptake studies performed using the hybrid exosomes revealed that the interactions between the developed exosomes and cells could be modified by changing the lipid composition or the properties of the exogenous lipids. These results suggest that the membrane-engineering approach reported here offers a new strategy for developing rationally designed exosomes as hybrid nanocarriers for use in advanced drug delivery systems.

CagA, encoded by cytotoxin-associated gene A (cagA), is a major virulence factor of Helicobacter pylori, a gastric pathogen involved in the development of upper gastrointestinal diseases. Infection with cagA-positive H. pylori may also be associated with diseases outside the stomach, although the mechanisms through which H. pylori infection promotes extragastric diseases remain unknown. Here, we report that CagA is present in serum-derived extracellular vesicles, known as exosomes, in patients infected with cagA-positive H. pylori (n = 4). We also found that gastric epithelial cells inducibly expressing CagA secrete exosomes containing CagA. Addition of purified CagA-containing exosomes to gastric epithelial cells induced an elongated cell shape, indicating that the exosomes deliver functional CagA into cells. These findings indicated that exosomes secreted from CagA-expressing gastric epithelial cells may enter into circulation, delivering CagA to distant organs and tissues. Thus, CagA-containing exosomes may be involved in the development of extragastric disorders associated with cagA-positive H. pylori infection.

Immune checkpoint inhibitors and adoptive transfer of gene-engineered T cells have emerged as novel therapeutic modalities for hard-to-treat solid tumors; however, many patients are refractory to these immunotherapies, and the mechanisms underlying tumor immune resistance have not been fully elucidated. By comparing the tumor microenvironment of checkpoint inhibition–sensitive and –resistant murine solid tumors, we observed that the resistant tumors had low immunogenicity. We identified antigen presentation by CD11b⁺F4/80⁺ tumor–associated macrophages (TAMs) as a key factor correlated with immune resistance. In the resistant tumors, TAMs remained inactive and did not exert antigen-presenting activity. Targeted delivery of a long peptide antigen to TAMs by using a nano-sized hydrogel (nanogel) in the presence of a TLR agonist activated TAMs, induced their antigen-presenting activity, and thereby transformed the resistant tumors into tumors sensitive to adaptive immune responses such as adoptive transfer of tumor-specific T cell receptor–engineered T cells. These results indicate that the status and function of TAMs have a significant impact on tumor immune sensitivity and that manipulation of TAM functions would be an effective approach for improving the efficacy of immunotherapies.