Antitumor Peptide-Based Vaccine in the Limelight

Abstract

The success of the immune checkpoint blockade has provided a proof of concept that immune cells are capable of attacking tumors in the clinic. However, clinical benefit is only observed in less than 20% of the patients due to the non-specific activation of immune cells by the immune checkpoint blockade. Developing tumor-specific immune responses is a challenging task that can be achieved by targeting tumor antigens to generate tumor-specific T-cell responses. The recent advancements in peptide-based immunotherapy have encouraged clinicians and patients who are struggling with cancer that is otherwise non-treatable with current therapeutics. By selecting appropriate epitopes from tumor antigens with suitable adjuvants, peptides can elicit robust antitumor responses in both mice and humans. Although recent experimental data and clinical trials suggest the potency of tumor reduction by peptide-based vaccines, earlier clinical trials based on the inadequate hypothesis have misled that peptide vaccines are not efficient in eliminating tumor cells. In this review, we highlighted the recent evidence that supports the rationale of peptide-based antitumor vaccines. We also discussed the strategies to select the optimal epitope for vaccines and the mechanism of how adjuvants increase the efficacy of this promising approach to treat cancer.

Exploring Immunological Effects and Novel Immune Adjuvants in Immunotherapy for Salivary Gland Cancers

“…Autoimmune T cells activated by ICIs cause immune-related adverse effects. Tumor-specific immunotherapies are designed to avoid the risk of autoimmunity by targeting specific proteins expressed in tumor cells but not in normal cells [ 93 ]. To establish tumor-specific immunotherapy, the identification of tumor-derived molecules is necessary.…”

“…Because there is no need for expensive genetic transduction and T-cell expansion ex vivo, it is relatively simple to switch antigens in cancer vaccines compared to CAR T therapy, in situations of antigen loss. An enormous number of epitopes derived from tumor-derived antigens have been identified as vaccine sources [ 93 ]. After vaccine administration, these epitopes bind to HLA molecules on antigen-presenting cells, followed by the expansion of tumor-reactive T cells.…”

“…In addition to TAAs, recent advances in genetic sequencing have enabled the detection of tumor-specific antigens (TSA) that are expressed only in tumor cells. TSA is considered an ideal cancer vaccine target because of its high immunogenicity and low cross-reactivity with normal tissues [ 93 ]. Neoantigens are TSAs generated by mutations in tumor cells.…”

Immunogenicity of peptide‐based vaccine composed of epitopes from Echinococcus granulosus rEg.P29

“…Being able to specifically target critical neutralizing peptides in the immune response while avoiding the induction of antibody specificity does not have a protective effect and may even be deleterious, which are potential advantages of peptide vaccines 8 . Presently, peptide vaccines have been extensively studied for the prevention and treatment of tumors, neurodegenerative diseases, hepatocellular carcinoma, foot‐and‐mouth disease, and other diseases, representing a new direction for vaccine development 9–13 . However, similar to any new approach, many challenges remain in the development and application of peptide vaccines.…”

“…8 Presently, peptide vaccines have been extensively studied for the prevention and treatment of tumors, neurodegenerative diseases, hepatocellular carcinoma, foot-and-mouth disease, and other diseases, representing a new direction for vaccine development. [9][10][11][12][13] However, similar to any new approach, many challenges remain in the development and application of peptide vaccines. For instance, due to their relatively small size, peptides typically have weak immunogenicity and require carrier molecules, delivery carriers or adjuvants to enhance chemical stability and induce a moderate immune response.…”