The complement lysozyme sequence in immune bacteriolysis

Abstract

Suspensions of Escherichia coli were not affected by lysozyme alone, but in solutions of appropriate pH and ionic strength some lysozyme was bound to the bacterial surface and remained available for action if the bacteria were subsequently treated with antibody and complement. In the presence of antibody, complement had a relatively prolonged action on E. coli ending in lysis. However, from an early stage in the reaction this lysis could be accelerated by adding lysozyme. The results suggest that human complement acted on the outer, lipoprotein—lipopolysaccharide layers of the bacterial cell wall and so gave lysozyme access to the deeper mucopeptide.

When the number of bound lysozyme molecules per bacterium was less than 10,000–20,000 the lysozyme effect decreased rapidly. However, many of these molecules may have been inactivated by K antigen.