Interestingly, a family of proteins stored in the RB, including SO7 (also known as GX3262, RB1 or B antigen), induce immune-protective responses in the chicken and are potential candidates for inclusion in recombinant-based vaccines for coccidiosis (Crane et al., 1991; Kopko et al., 2000; Song et al., 2013). Here, RB1 is linked to coccidiosis.