IN-SILICO MULTI-EPITOPE VACCINE CANDIDATE DESIGN AGAINST CHICKEN COCCIDIOSIS
Author:
Osuji Charles and Abubakar Salisu
This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
The economic burdens of coccidiosis pose a very significant challenge to commercial poultry farmers. Not only does it threaten human nutritional and pecuniary endeavors, but efforts to control the infection through hygienic measures and biosecurity are insufficient to contain it. Drug treatments using anti-coccidiosis agents are somewhat ineffective owing to frequent resistance concerns which prompted exploration into chemoprophylaxis as a more viable solution. However, challenges of the low immune response, side effects, and cost, are undermining factors in using the existing vaccines. By adopting an immunoinformatics-aided procedure, this study designed a potential broad-spectrum vaccine for chicken coccidiosis, mining from the various chicken Eimeria apical membrane antigens (AMAs) and other key sporozoite surface antigens (SSAs). Standard structural Bioinformatics tools were utilized to identify antigenic epitopes from the important proteins involved in the chicken Eimeria pathogenesis and conjugate them into a multi-epitope subunit vaccine. A potential broad-spectrum sub-unit vaccine construct consisting of 26 selected epitopes was designed through stringent analyses of immunological, physicochemical, structural, and molecular validations. While appropriate linkers were used for the conjugation, Beta defensin-3 adjuvant, and Padre Sequences were included to enhance the immune response. The resulting construct is a stable and promising vaccine candidate for further analysis and wet laboratory validation.
1. INTRODUCTION
Chickens are undeniably one of the primary sources of animal protein for human consumption and are known for their high-quality protein products (Mesa-Pineda et al., 2021; Britez et al., 2023). Coccidiosis in chickens is an enteric pathogenic disease by Eimeria species that results in substantial global economic losses (Blake et al., 2020). As part of the Apicomplexan family, these parasites have a unique mechanism of invading host cells through membrane proteins aided by specialized organelles like micronemes which are crucial to their successful hosts’ cell invasion (Suarez et al., 2017; Burrell et al., 2020). The Eimeria pathogens that cause chicken coccidiosis thrive in the intestinal epithelial cells after being transmitted through oocysts, leading to varying degrees of morbidity and mortality in poultry (Zaheer et al., 2022). These pathogenic species of Eimeria which include tenella, acervulina, praecox, among others, are known to cause chicken coccidiosis (Clark et al., 2017; Abbas et al., 2019). Coccidiosis pathophysiology begins primarily with the pathogen’s invasion, which involves interactions between sporozoites and host cells, then migration to enterocytes, and subsequent proliferation. This leads to disruption of the normal mucosal cellular function resulting in increased permeability of the intestinal wall and poor nutrient absorption (Madlala et al., 2021). Consequential symptoms like fluid loss, diarrhea, weight loss, and intestinal hemorrhaging follow suit and most times culminate in death (Vrba et al., 2010). The severity and clinical outcomes depend on various factors like host-pathogen interactions, the species involved, the dose of infection, and the environment (Britez et al., 2023). Therefore, pathogenicity in chicken Eimeria infections varies from mild to severe (Tewari et al., 2011). Developing broad-spectrum vaccines that target various species of Eimeria pathogens in chickens is essential due to the negative impacts of coccidiosis on global economic and nutritional well-being. For many years, anti-coccidial drugs have been the primary method of control, but frequent cases of drug resistance have negatively affected its effectiveness (Zhang et al., 2012). Vaccines are considered the most effective method due to their efficacy and low likelihood of resistance development. However, the drawbacks of current vaccines include their limited broad-spectrum effectiveness, side effects, and costs, as most are from live and attenuated organism sources. The low efficiency associated with these vaccine preparations is primarily due to the antigenic variation among Eimeria species, driven by retro-transposons, resulting in limited cross-protection (Hinsu et al., 2018). Currently, there is rarely any chicken coccidiosis vaccine that provides protection against a wide range of Eimeria species. Immunoinformatics-designed multi-epitope vaccines are gaining recognition for their cost-effectiveness and flexibility in combating various pathogens. Subunit vaccines, unlike conventional ones, are safer because they do not contain infectious particles, reducing the risk of reinfection. Computationally optimized subunit vaccines are being recommended for disease prevention due to their overwhelming advantages over conventional vaccines (Sharma et al., 2021). Given the characteristic features of surface antigens as immune targets and the role of sporozoites in coccidiosis, surface proteins from sporozoite antigens were selected for this study. These proteins were chosen for their strong host-parasite interaction, ability to facilitate attachment and invasion, immune protection, and low variability (Vo et al., 2021). They include; the AMA-1 and other surface antigens like the Microneme and Immune-mapped proteins (MIC and IMP) (Liu et al., 2019; Wang et al., 2023). This in-silico study, therefore aimed at mining multiple viable epitopes of immunological interest from the various known chicken coccidiosis pathogens and designing a potential broad-spectrum vaccine construct via a stringent evaluation methodology.










Pages | 40-45 |
Year | 2025 |
Issue | 1 |
Volume | 5 |