Outer membrane protein A (OmpA) binds to and activates human macrophages.

Outer membrane protein (Omp)A is highly represented and conserved in the Enterobacteriaceae family. Using a recombinant OmpA from Klebsiella pneumoniae (P40), we have analyzed the interaction between OmpA and macrophages. We report that Alexa488-labeled P40 binds (at 4 degrees C) to murine and human macrophages in a dose-dependent manner and is rapidly internalized (at 37 degrees C).