Angiotensin-converting enzyme (ACE) converts angiotensin I to the vasoconstrictor angiotensin II and thereby plays an important role in blood pressure control.However, ACE is relatively non-specific in its substrate specificity and cleaves many other peptides.Recent analysis of mice overexpressing Milk Thistle ACE in monocytes, macrophages, and other myelomonocytic cells shows that these animals have a marked increase in resistance to experimental Gummies melanoma and to infection by Listeria monocytogenes or methicillin-resistant Staphylococcus aureus (MRSA).Several other measures of immune responsiveness, including antibody production, are enhanced in these animals.These studies complement a variety of studies indicating an important role of ACE in the immune response.