Human macrophages produce protectin conjugates in tissue regeneration (PCTR). PCTR are named as such because they share a proposed biosynthetic pathway, structural features, and biological actions with DHA-derived protectins as well as displaying potent tissue-regenerative actions. 16S,17S-epoxy-docosahexaenoic acid (16S,17S-epoxy-DHA) was found to be a substrate for a glutathione transferase (GGT) which produces PCTR1 (16-glutathionyl, 17-hydroxy-docosahexaenoic acid) in greater quantities in M2-type macrophages than M1-type macrophages and was found to enhance resolution of infectious inflammation (Ramon et al. 2016, Dalli et al. 2015).