Center for Molecular Medicine Cologne 1 article published in JoVE Immunology and Infection Highly Efficient Transfection of Primary Macrophages with In Vitro Transcribed mRNA Marc Herb1, Alina Farid1, Alexander Gluschko1, Martin Krönke1,2,3,4, Michael Schramm1 1Institute for Medical Microbiology, Immunology and Hygiene, Faculty of Medicine and University Hospital Cologne, University of Cologne, 2Center for Molecular Medicine Cologne, 3Cologne Cluster of Excellence on Cellular Stress Responses in Aging-associated Diseases (CECAD), 4German Center for Infection Research (DZIF) Macrophages, especially primary macrophages, are challenging to transfect as they specialize in detecting molecules of non-self origin. We describe a protocol that allows highly efficient transfection of primary macrophages with mRNA generated from DNA templates such as plasmids.