LAUSR

Toxoplasma gondii (T. gondii) that can infect most warm-blooded animals and humans, is an obligate intracellular apicomplexan parasite with a wide host range. About one-third of the world's population is infected with this parasite. While toxoplasmosis progresses asymptomatically in individuals with a strong immune system, it can cause serious clinical manifestations and death in immunocompromised individuals. The parasite is transmitted to humans through the consumption of water and food contaminated with cat feces, as well as raw or undercooked animal products, congenital infection and blood/organ transplantation. Additionally, T. gondii is often observed in farm animals such as sheep and goats. Clinical manifestations and abortions caused by T. gondii in sheep and goats lead to enormous economic loss worldwide. There is a commercial vaccine against T. gondii, called Toxovax (MSD, New Zealand) that can only be used in sheep. For these reasons, there is a need for innovative T. gondii vaccine that is harmless, easily produced, which can prevent losses and be used in all living things. Advances in immunology, molecular biology, genetic, biotechnology and proteomics bring new perspectives to vaccine studies. Studies in innovative vaccine studies against T. gondii have accelerated with the discovery of new antigens by in vitro screenings, and bioinformatic analyzes, the use of various expression systems and new adjuvant types. Recombinant protein vaccines are biotechnological vaccines that are frequently preferred due to their rapid and easy production in various expression systems, availability of very and high purity products, ease of manipulation and stimulation of both cellular and humoral immune responses. Recombinant protein vaccines, developed by biotechnological methods, are promising tools for providing a protective immune response against toxoplasmosis. In this review, an overview of the parasite complex life cycle, its pathogenesis, humoral and cellular immune responses in the host, and recombinant protein vaccine studies developed against the parasite are presented. Keywords: Toxoplasma gondii, recombinant protein vaccines, biotechnology, immunization.