Vegetative C. sordellii bacteria are phagocytosed via class A scavenger receptors (CASR). PGE2 stimulated intracellular cAMP synthesis by adenylate cyclase (AC) following ligation of the Gαs-coupled EP2 and EP4 receptors. The cAMP burst in turn activated the type I isoform of protein kinase A (PKA-RI), which is involved in suppressing the internalization of C. sordellii. Pharmacological tools used in these experiments include the EP2 agonist butaprost free acid (BFA), the EP2 agonist L-902,688, the EP2 antagonist AH-6809, the EP4 antagonists ONO AE1-208, and the PKA RI agonist 2-Cl-8-MA-cAMP.