TOXOPLASMA GONDII ADAPTATION ON DIFFERENT HOSTS

Toxoplasma gondii is an obligate intracellular parasite infecting an estimated 30% of the human population worldwide. The infection it produces can pose serious health risks in immunocompromised patients or during pregnancy. Toxoplasma is also considered one of the most successful parasites in nature since it can infect almost any warm blooded animal.

The interaction between Toxoplasma and any given host appears to be dependent on allelic differences (both sequence polymorphisms and copy number variants) among effectors secreted by the parasite into the host cell. To try and gain insight into how Toxoplasma has evolved to be such a generalist, an ability that is likely dependent on these polymorphic genes, and what cost this has on transmission to other hosts, we have conducted an “in-lab evolution study”. We used a Toxoplasma strain that has been passed in vivo in mice for several decades, and passed it in tissue culture in different host cells (Human, Murine and Bovine fibroblasts). Following approximately 200 generations in the different host cell lines we assessed the growth, virulence and expression profile (transcriptome) of the evolved strains. Preliminary results indicate that passage in different hosts results in remarkable differences in growth phenotypes of the evolved strains and transcriptomic data implicate major differences in the expression profile of surface protein gene families in this evolution.