A review of Eimeria antigen identification for the development of novel anticoccidial vaccines

Abstract

Coccidiosis is a major poultry disease which compromises animal welfare and costs the global chicken industry a huge economic loss. As a result, research entailing coccidial control measures is crucial. Coccidiosis is caused by Eimeria parasites that are highly immunogenic. Consequently, a low dosage of the Eimeria parasite supplied by a vaccine will enable the host organism to develop an innate immune response towards the pathogen. The production of traditional live anticoccidial vaccines is limited by their low reproductive index and high production costs, among other factors. Recombinant vaccines overcome these limitations by eliciting undesired contaminants and prevent the reversal of toxoids back to their original toxigenic form. Recombinant vaccines are produced using defined Eimeria antigens and harmless adjuvants. Thus, studies regarding the identification of potent novel Eimeria antigens which stimulate both cell-mediated and humoral immune responses in chickens are essential. Although the prevalence and risk posed by Eimeria have been well established, there is a dearth of information on genetic and antigenic diversity within the field. Therefore, this paper discusses the potential and efficiency of recombinant vaccines as an anticoccidial control measure. Novel protective Eimeria antigens and their antigenic diversity for the production of cheap, easily accessible recombinant vaccines are also reviewed.

A Novel Rhoptry Protein as Candidate Vaccine against Eimeria tenella Infection

“…However, the rise in drug resistance and public pressure for restrictions on foodborne animal chemicals continue to drive the development of anti-coccidiosis vaccines [3,38,39]. Therefore, it is urgent to develop safe and effective vaccines against avian coccidiosis [7,21,40]. The sporozoite stage plays a critical role in invasion.…”

“…Conventional control strategies primarily rely on anticoccidial drugs [3,6]. However, alternative control strategies are urgently needed due to the rapid emergence of drug-resistant parasites, the high cost of new drug development and the increasing legislation restrictions on the use of anticoccidial drugs [7,8]. Although live oocyst vaccines are used commercially in some regions, virulence variation and the high cost of vaccine production restrict the application of live vaccines [9,10].…”

“…However, CoxAbic is a subunit vaccine prepared from E. maxima affinity-purified gametocyte antigens (APGAs), and it is limited by a complicated purification process and high production cost [3,11]. These drawbacks have driven the development of new control strategies, especially the screening of effective immunoprotective proteins for the development of a subunit vaccine [7]. E. tenella belongs to the phylum Apicomplexa, and it has rhoptries (ROP), micronemes (MIC) and dense granule (GRA) secretory organelles.…”

EtMIC3 and its receptors BAG1 and ENDOUL are essential for site-specific invasion of Eimeria tenella in chickens

“…Chicken Eimeria are obligate intracellular parasitic protozoa that develop within intestinal epithelial cells of chickens. Infection of one or multiple Eimeria species causes coccidiosis which brings great economic losses to the poultry industry worldwide [1]. Currently, control of avian Eimeria mainly depends on usage of coccidiostats and live coccidia vaccines.…”

Comparative Analysis of Evaluation Parameters in Broiler Chickens Infected With Major Parasitic Species of Eimeria 

“…There are seven species of Eimeria known to infect chickens, including E. acervulina, E. maxima, E. necatrix, E. brunetti, E praecox, E. mitis and E. tenella. Each species invades the intestinal epithelial tissues of the host, eliciting a variety of clinical effects in infected chickens, including necrotic gut lesions, reduced feed conversion rate and weight gain, increased mortality, and greater susceptibility to secondary pathogens [5][6].…”