OPN1LW and cyst: These immunological parameters were exactly correlated with the protection induced by VLPs immunization, in which cyst size, cyst counts, and body weight loss was lowest and the survival rate of mice was highest in ROP(4 + 13) VLPs vaccination, followed by ROP4+ROP13 VLPs and ROP4 VLPs or ROP13 VLPs in order.