Cell Wall Component Which Affects the Ability of Serum to Promote Phagocytosis and Killing of Staphylococcus aureus.

The role of various cell wall components of nonencapsulated Staphylococcus aureus in phagocytosis and killing was studied. Adsorption of human serum with S. aureus cell walls, or trypsin-digested cell walls, reduced the rate of phagocytosis and killing of S. aureus by human-blood leukocytes when compared to unadsorbed serum. When the various components of the cell walls were used for adsorption, only the intact mucopeptide was found to remove these factors. Products of digestion of this mucopeptide with several enzymes were found to be inactive when used for adsorption of human serum. Other components tested were teichoic acids alpha, beta, and combinations of both and protein A. When used in equivalent amounts, these were found to have no effect on the removal of serum factors necessary for phagocytosis and intracellular killing of S. aureus.