Chinese scientists report they have developed a new type of precise therapeutic vaccine against leukaemia.
The vaccine uses self-healing polylactic acid microcapsules for co-encapsulating a new epitope peptide and an anti-PD-1 antibody. It was developed by researchers from the Institute of Process Engineering (IPE) of Chinese Academy of Sciences and Zhujiang Hospital of Southern Medical University.
In the study, published in Nature Biomedical Engineering, the researchers identified high expression of Eps8 and PD-1/PD-L1 in leukaemia patients. They realised these could be used as a new type of leukaemia antigen and a checkpoint target for a vaccine, respectively.
To develop a leukaemia vaccine for treatment, EPS8 epitope peptides and anti-PD-1 antibodies were loaded into polylactic acid microcapsules. The microcapsule material is FDA-approved and naturally degrades over time in the body.
The researchers found that after a single injection of the microcapsules, their degradation at the local injection site led to recruitment of activated antigen-presenting cells and sustained release of both cargos.
Professor Wei Wei from IPE said: “With the synergism of these two aspects, we observed a significant improvement in specific Cytotoxic T Lymphocyte (CTL) activation.”
They found that the microcapsule-based formulation performed better than the ISA adjuvant (commercialised adjuvant) in several mouse leukaemia models, including a humanised patient-derived xenograft model.
“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," added Professor Ma Guanghui from IPE.
Xie X, Hu Y, Ye T, Chen Y, Zhou L, Li F, Xi X, Wang S, He Y, Gao X, Wei W, Ma G, Li Y. (2020) “Therapeutic vaccination against leukaemia via the sustained release of co-encapsulated anti-PD-1 and a leukaemia-associated antigen.” Nature Biomedical Engineering, doi: 10.1038/s41551-020-00624-6