A comprehensive review of Toxoplasma gondii biology and host-cell interaction: Challenges for a plant-based vaccine

Abstract

Toxoplasmosisis a worldwide-distributed infection caused by Toxoplasma gondii, which causes a wide range of clinical syndromesin humans, mammals and birds. T. gondiiis considered a parasite of veterinary and medical importance, because it maycause abortion or congenital disease in its intermediate hosts. Despite theeconomic losses associated with T. gondiiinfection in farm animals and the socio-economic impact caused by this zoonoticdisease in the human population, there is no effective treatment available forhumans or animals able to eliminate the parasite from the host once the chronicinfection has been established. The only commercial vaccine is the S48 strainof attenuated tachyzoites for use in sheep. However, this vaccine causes sideeffects, has a short life time and induces a short-term immunity. So far, noacellular vaccine against toxoplasmosis has been commercialized. In fact, futurechallenges include the development of an effective vaccine to preventtoxoplasmosis. Most parasitologists and vaccinologists agree that futureefforts should be concentrated on developing multi-antigen vaccines and moreefficient delivery systems able to express heterologous proteins abundantly aswell as on searching for immunization schedules and adequate adjuvants toenhance the protective responses. To achieve this, platforms for the productionof acellular vaccines based on the use of plants can have an important role.