Release of stress proteins from Mesocestoides corti is a brefeldin A-inhibitable process: evidence for active export of stress proteins

Abstract

Substantial evidence indicates that molecules released by infectious organisms affect virulence and influence immunity to infection. The characterization of extracellular molecules and their mechanism of release is therefore critical to understanding host-parasite relationships. The cestode parasite Mesocestoides corti is known to release at the larval stage several molecules including the heat shock proteins hsp70 and hsp60. In this report, it is shown that several molecules released by M. corti, including 70- and 60-kDa proteins, are induced by a temperature shift from room temperature to 37 degrees C. Such a shift is comparable to the thermal stress of parasites transmitted from insect vector to vertebrate host. By drug inhibition studies and Western blot (immunoblot) analyses, it is shown that M. corti hsp70 and hsp60 as well as other released molecules are actively exported. The active release of stress proteins by parasites has not been described and may play a critical role in the disease process.