Epitope-Based Vaccines: The Next Generation of Promising Vaccines Against Bacterial Infection

Abstract

The increasing resistance of bacteria to antibiotics has underscored the need for new drugs or vaccines to prevent bacterial infections. Reducing multidrug resistance is a key objective of the WHO's One Health initiative. Epitopes, the key parts of antigen molecules that determine their specificity, directly stimulate the body to produce specific humoral and/or cellular immune responses. Epitope-based vaccines, which combine dominant epitopes in a rational manner, induce a more efficient and specific immune response than the original antigen. While these vaccines face significant challenges, such as epitope escape or low immunogenicity, they offer advantages including minimal adverse reactions, improved efficacy, and optimized protection. As a result, epitope-based vaccines are considered a promising next-generation approach to combating bacterial infections. This review summarizes the latest advancements, challenges, and future prospects of epitope-based vaccines targeting bacteria, with a focus on their development workflow and application in antibiotic-resistant pathogens with high mortality rates, including Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. The goal of this review is to provide insights into next-generation vaccination strategies to combat bacterial infections associated with antibiotic resistance and high mortality rates.

Keywords: B-cell epitopes; Staphylococcus aureus; T-cell epitopes; bacterial vaccines; epitope-based vaccines.

Figure 1

The procedure for developing bacterial epitope-based vaccines. LBL, linear B lymphocyte epitope; CBL, conformational B lymphocyte epitope; CTL, cytotoxic T lymphocyte epitope; HTL, helper T lymphocyte epitope; TLR, Toll-like receptor; CTB, cholera toxin subunit B; LTB, heat-labile enterotoxin B; RplL, 50S ribosomal protein L7/L12; Ply, pneumolysin; hBD3, human beta-defensin 3.

Figure 2

Summary of known target antigens (highlighted in red) used for designing epitope-based vaccines against S. aureus, S. pneumoniae, S. pyogenes, K. pneumoniae, A. baumannii, and P. aeruginosa. Target antigens in red indicate those with known immunogenicity and/or protective effects in animal models. Target antigens in blue indicate those predicted using bioinformatics tools but lacking in vitro and in vivo experimental validation.