To determine whether an intact sphingolipid biosynthetic pathway is a general prerequisite for the entry of pathogens in professional phagocytes, we performed parallel infections of wild-type and Sptlc2−/− RAW264.7 cells with a fluorescent reporter strain of herpes simplex virus 1 (HSV-1) encoding a fusion of the viral protein VP26 and mCherry (28). The gene discussed is SPTLC2; the disease is infection.