Designing a chimeric multi-epitope vaccine against Candida auris using reverse vaccinology approach targeting the agglutinin-like protein N-terminal domain

Abstract

Candida auris is an emerging multidrug resistant fungal pathogen associated with high mortality rates, rapid global dissemination and resistance to conventional antifungal therapies. It’s remarkable ability to evade host immune responses and persist in health care setting demands the development of effective immunotherapeutic strategies. In this study, a reverse vaccinology and immunoinformatics based approach was employed to design a novel chimeric multi-epitope vaccine targeting surface expose N-terminal domain of the agglutinin like protein involved in host pathogen interactions. High affinity B-cell and T-cell (MHC class I and II) epitopes were identified and screened based on antigenicity, allergenicity, toxicity and population coverage. Selected epitopes were assembled using optimized linkers (EAAAK, AAY and GPGPG) along with an adjuvant to enhance immunogenicity and structural stability. Physicochemical characterization, structural validation, molecular docking with human Toll-like receptor 4 (TLR4), Normal Mode Analysis (NMA), immune simulation, codon optimization and in silico cloning into the pET28a+ vector were performed to evaluate the vaccine construct. The selected epitopes demonstrated a global population coverage of 97.31%. the final vaccine construct was predicted to highly antigenic, non-allergenic, structurally stable and soluble. Molecular docking analysis revealed strong and stable interactions between the vaccine construct and human TLR4, with a binding energy of − 906.1 kcal/mol. Normal Mode Analysis further supported the structural stability of the vaccine receptor complex. Immune simulations predicted robust primary and secondary responses characterized by elevated IgG and IgM antibodies along with a Th1-skewed cytokine profile dominated by IFN-γ and IL-2 expression. Codon optimization and in-silico cloning indicated favorable translational efficiency in the pET28a+ expression system. The designed chimeric multi epitope vaccine demonstrated promising immunogenic, structural and receptor binding properties against Candida auris. These findings suggest that the proposed vaccine construct may serve as a potential candidate for further experimental validation and future development of effective immunotherapeutic interventions against multidrug- resistant fungal infections.