The deposition of C5b-9 complexes and its precursors on E. coli J5 during complement activation enhances uptake and toxicities of gentamicin.

The complement system provides the host with protection against pathogenic agents and in some cases can result in damage to host tissue. However, the exact mechanism of how complement kills gram-negative bacteria in lysozyme-neutralized and or lysozyme-depleted serum is still under active investigation. In previous studies, it has been demonstrated that inner membrane damage by the membrane attack complex contributes to depolarization and the subsequent collapse of the membrane potential.