Virus-like particle: a nano-platform that delivers cancer antigens to elicit an anti-tumor immune response

Abstract

Virus-like particles (VLPs), as a unique form of nanocarrier, predominantly encompass hollow protein shells that exhibit analogous morphology and structure to naturally occurring viruses, yet devoid of genetic material. VLPs are considered safe, easily modifiable, and stable, making them suitable for preparation in various expression systems. They serve as precise biological instruments with broad applications in the field of medical biology. Leveraging their unique structural attributes and facile modification capabilities, VLPs can serve as an effective platform for the delivery of tumor antigens, thereby stimulating the immune system and facilitating the eradication of tumor cells.

Keywords: nanoplatform; tumor antigens; tumor immunotherapy; tumor vaccine; virus-like particles.

Figure 1

Overview of VLPs-based vaccine expression, purification and formulation. The production of tumor vaccines based on VLPs is mainly through: (1) Cloning of the viral structural genes of interest and expression of viral proteins with self-assembling ability in a suitable expression platform. (2) Purification of VLPs. (3) Adjuvant and additional ingredients are added to the vaccine formulation to finally achieve a safe, efficient and effective product for vaccination.

Figure 2

Conjugation method of VLPs with tumor antigens. (A) Gene fusion to link antigens; (B) Amino acid conjugation. (C) Mechanism of antigen ligation using the Sortase technology. (D) Mechanism of antigen ligation using the Spy-Catcher technology.

Figure 3

Mechanisms by which VLPs-based antigen delivery systems activate antitumor immune responses. After being phagocytosed and processed by dc through the PRR-mediated endocytic pathway, VLPs are presented to MHC-I and MHC-II for recognition by CD8⁺ and CD4⁺ T cells. CD4⁺ T cells differentiate into TH2 and TH1 cells that are involved in inflammatory response and in sustaining the activity of CD8⁺ T cells (cytotoxic T cells), respectively. CD8⁺ T cells exert cytotoxic activity on tumor cells.