Role of the 52 KDa thioredoxin protein disulfide isomerase of Toxoplasma gondii during infection to human cells

• Recombinant 52 KDa protein disulfide isomerase from Toxoplasma was obtained.
• Exogenous recombinant protein reduced entry of parasite to human cell line.
• Expression of Toxoplasma pDI was higher before entry of parasite to host cell.
• Recombinant Toxoplasma PDI labeled membrane of human host cell line.
• Toxoplasma PDI is involved in parasite first steps of invasion.

Toxoplasma protein disulfide isomerase (PDI) is a 52 KDa thioredoxin of interest because have a great immunogenicity for humans. We cloned and produced a recombinant protein (recTgPDI) used to test its effect during infection to different human cell lines (epithelial and retinal). We also determine if there were differences in gen expression during in vitro infection. Expression of the gen was lower after entry into the host cells. PDI's inhibitors bacitracin and nitroblue tetrazolium reduced the percent of infected cells and small amounts of recTgPDI proteins interfered with the invasion step. All these results support a role of Toxoplasma PDI during the first steps of infection (adhesion and invasion). Toxoplasma PDI is a protein linked to early steps of invasion, it would be of importance to identify the host proteins substrates during invasion steps.

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