Immunoprecipitation of digoxigenin-labeled calreticulin. Purified calreticulin (CRT) from either Sf9 or HL-60 cells was derivatized with digoxigenin as in Fig 6 and then analyzed either without immunoprecipitation (−) or after immunoprecipitation with anticalreticulin or non-immune serum (NIS). Analysis was performed as in Fig 6 by immunoblotting with either antidigoxigenin (upper panel) or anticalreticulin (lower panel).