As one of the malignant tumors of the hematological system, leukemia seriously threatens human health. Although conventional chemotherapy has made progress, many patients still face difficult problems, including severe toxicity and insensitivity to chemotherapy. Recently, immunotherapy has become a new breakthrough in the treatment of leukemia. Although multiple vaccinations have been carried out in many programs, the effect has not yet reached the expected level.

In response, on October 12th, researchers from the Institute of Process Engineering, Chinese Academy of Sciences and Zhujiang Hospital of Southern Medical University developed a therapeutic vaccine that can co-encapsulate epitope peptides and PD-1 antibodies in self-healing microcapsules In order to accurately treat leukemia. In the new vaccine, epitope peptides and PD-1 antibodies can be easily, gently, and efficiently loaded into polylactic acid microcapsules through the unique self-repair function of microcapsules. Related research results were published on "Nature Biomedical Engineering".

Specifically, in order to construct this vaccine, researchers used polylactic acid (a material approved by the FDA) to synthesize microspheres with a huge porous structure (giga-porous microspheres), which can effectively load mixed epitope peptides and peptides in a diffusion manner. PD-1 antibody. Because the pores on the surface of the microspheres have unique healing properties under mild conditions, epitope peptides and PD-1 antibodies can be effectively co-encapsulated as cargo in the final microcapsules.

In mouse experiments, after a single administration, the beneficial chemokines and cytokines produced at the vaccination site recruited and activated antigen-presenting cells. At the same time, the gradual degradation of the microcapsules leads to the sustained release of the two wrapped goods. Correspondingly, epitope peptides can be effectively absorbed by recruited antigen-presenting cells, while PD-1 antibodies are transported to the lymph for T cell regulation. Through the coordination of these functions, researchers have achieved substantial improvements in the activation of specific cytotoxic lymphocytes.

The researchers also verified the availability of new vaccines using various epitope peptides in different models, such as murine leukemia, humanized cell line leukemia xenografts (CDX), and patient-derived leukemia xenografts (PDX) models . In all leukemia treatment models, the microcapsule-based preparations showed better performance than ISA adjuvants (commercial adjuvants), systematically inhibiting leukemia with almost no abnormalities. With its high performance and safety, the vaccine can be used as a promising immunotherapy to treat leukemia clinically.

The researchers emphasized that based on the advantages of the FDA-approved polylactic acid material, the convenience of preparing vaccine preparations, the diversity of vaccine components, and the excellent therapeutic effect, this microcapsule-based vaccine has great potential for clinical transformation. A peer reviewer of "Nature Biomedical Engineering" described the study as a "comprehensive new platform." The reviewer also emphasized that this work is "exciting and convincing."