Moa Viklund, Johanna Fredriksson, André Holdfeldt, Simon Lind, Henrik Franzyk, Claes Dahlgren, Martina Sundqvist and Huamei Forsman J Immunol April 1, 2022, 208 (7) 1632-1641; DOI: https://doi.org/10.4049/jimmunol.2101039 Key Points Neutrophils and FPR knock-in/knockout cells provide insights into receptor recognition. The S. aureus peptide PSMα2 is an FPR2 agonist that triggers biased signaling. Peptide parts that confer FPR1/FPR2 selectivity and alter signaling are identified.