HES is the H. polygyrus Excretory-Secretory product, collected from adult worms maintained in serum free culture as described by our laboratory and by other investigators.  "HES" generally refers to adult worm secretions; information is also available on ES from developing tissue-stage larvae.

The current Maizels Lab HES protocol is available to download (pdf file). There are >300 known components, the major ones can be visualised by 2-D gel electrophoresis and silver staining.