Apelin-17(human, bovine) TFA is an endogenous orphan G protein-coupled receptor APJ agonist. Apelin-17(human, bovine) TFA binds to human APJ receptors expressed in HEK 293 cells ( pIC 50 =9.02). Apelin-17(human, bovine) TFA inhibits the entry of some HIV-1 and HIV-2 into the NP2/CD4 cells expressing APJ.