Novel Oral papaya-based preventive and therapeutic vaccine for controlling different zoonotic Taeniid parasites: Current advances

Abstract

Zoonotic infections caused by Taenia and Echinococcus species are the most significant Taeniid parasitic diseases affecting human and animal health, particularly in regions with poor sanitation. Vaccination of intermediate hosts has proven effective in controlling these parasitic infections. In the case of Echinococcosis, targeted immunization programs have led to marked reductions in transmission, although global eradication remains unachieved. Similarly, sustained vaccination studies for cysticercosis have demonstrated the feasibility of interrupting transmission cycles. This review summarizes the current state of progress in the development of a novel, low-cost oral vaccine against zoonotic Taeniid parasites employing Carica papaya tissue cultures as a biofactory system. KETc7, a highly conserved protective antigen among Taeniid species, has been expressed in this plant tissue culture–based platform. C. papaya serves not only as an efficient vehicle for oral immunization but also exhibits intrinsic anthelmintic properties. The Taeniid oral papaya vaccine formulation consists of aqueous extracts from KETc7-transgenic papaya cells, combined with anthelmintic aqueous extracts derived from wild-type C. papaya cells. Importantly, transgenic and non-transgenic C. papaya cells suspension cultures were optimized under reproducible conditions to enable scalable production for the vaccine. By integrating biological knowledge of Taeniid parasites with advances in plant biotechnology, this review highlights the advances of a dual-action oral vaccine, both preventive and therapeutic, as a strategy to control with one vaccine different Taeniid infections in endemic regions, particularly where conventional injectable vaccination is limited by logistical and economic restrictions.