Much like any other form of cancer, leukemia—a group of cancers found in blood cells and the bone marrow—is difficult to treat. While medical interventions exist to tackle the disease, the variant, and progression of cancer play a crucial role in the outcome of treatments. Offering some hope, a new study has reported the development of a new kind of specific therapeutic vaccine against leukemia.

Researchers from the Zhujiang Hospital of Southern Medical University and Institute of Process Engineering (IPE) of Chinese Academy of Sciences, leveraged self-healing polylactic acid—a polymer of lactic acid—microcapsules in order to develop the novel vaccine

"With the advantages of FDA-approved polylactic acid material, convenience in preparing the vaccine formulation, diversity of vaccine components, and excellent therapeutic effect, the microcapsule-based vaccine exhibits great potential for clinical translation," said Prof. MA Guanghui, co-author of the study.

Vaccine
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Tackling the Expression of Specific Genes

Though the potential of treating leukemia using vaccines has been explored before, therapeutic results in clinical trials have continued to fall short of expectations. In this novel approach, the scientists used healing polylactic acid to co-encapsulate (covering a molecule at the core) a new epitope peptide(part of an antigen recognized by the immune system) and an antibody known as PD-1.

Here, the epitope peptides and PD-1 antibodies can be easily and efficiently placed into polylactic acid microcapsules, which were aided by their distinctive property of self-healing. The gene EPS8 (Epidermal growth factor receptor kinase substrate 8) and PD-1 (Programmed cell death protein 1) are found to be expressed highly in leukemia.

Expression of Cancer Genes
High expression of Eps8 and PD-1/PD-L1 in acute leukemia and construction of microcapsule vaccine loading with new epitope Eps8 and PD-1 antibody WEI Wei

Explaining the underlying principle of the vaccines, Prof. LI Yuhua, co-author of the study, said, "Our clinical findings revealed the high expression of EPS8 and PD-1/PD-L1 in leukemia patients, which could be respectively used as a new type of leukemia antigen and a checkpoint target for a leukemia vaccine."

Showing Immense Potential

Following a single dose of the vaccine, the deposition and degradation of the injected microcapsules at the site of injection were able to recruit activated antigen-presenting cells and provide a sustained release of both the vaccine components. "With the synergism of these two aspects, we observed a significant improvement in specific Cytotoxic T Lymphocyte (CTL) activation," said Prof. WEI Wei, co-author of the study.

The feasibility of the vaccine was also tested using other epitope peptides in different leukemia therapeutic models. In all the models, the microcapsule-based vaccine exhibited a superior effect, thus, highlighting its potential for use against numerous leukemia antigens clinically.

"With the advantages of FDA-approved polylactic acid material, convenience in preparing the vaccine formulation, diversity of vaccine components, and excellent therapeutic effect, the microcapsule-based vaccine exhibits great potential for clinical translation," concluded Prof. MA Guanghui, co-author of the study.