Potentiation of serum bactericidal activity by lysozyme.

The influence of lysozyme on serum bactericidal action was studied using lysozyme-depleted serum prepared by CMC absorption. It was found that serum action produces an intermediate bacterial form, termed RL, which could be killed by lysozyme but which was viable in its absence. Killing by lysozyme was concentration-dependent and could be inhibited by magnesium. The RL form may be significant in the intracellular killing of gram-negative bacteria by phagocytic cells.