Pull-down method to access the cell surface receptor for Toxoplasma gondii.

Protein X, which is expressed on the surface of Toxoplasma and is thought to interact with host molecules, was expressed as a GST recombinant protein, conjugated to sepharose 4B, and used to pull down biotin-labeled 293T cells. The product was analysis by 2D-PAGE and Western blotting. Mass spectrometry revealed the reacted spots from the gel to be heat shock proteins.