Surgery (IMAGE) University of Würzburg Caption After surgery, bacteria from the intestine can enter the organism. Special cells of the immune system located in the liver fight them. Credit Mercedes Gomez de Agüero Usage Restrictions None License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.