Opsonic recognition of staphylococci mediated by cell wall peptidoglycan: antibody-independent activation of human complement and opsonic activity of peptidoglycan antibodies
Verbrugh, H.A.; Van Dijk, W.C.; Peters, R.; Van Erne, M.E.; Daha, M.R.; Peterson, P.K.; Verhoef, J.
Journal of Immunology 124(3): 1167-1173
1980
ISSN/ISBN: 0022-1767 PMID: 7358981 Document Number: 158710
To determine the cell surface component(s) of importance in the opsonic recognition of staphylococci, the interactions of intact bacterial cells, isolated cell walls and purified cell wall components with human complement (C) and immunoglobulins were investigated. Intact cells of 5 strains of Staphylococcus aureus and 1 strain of S. epidermidis consumed human C via the classical and the alternative pathway. Activation of C resulted in the deposition of opsonically active C3 molecules on the surface of the staphylococci. All cell wall components contributed to the consumption of C via the antibody-dependent classical pathway. Activation of the alternative C pathway was mediated exclusively by the peptidoglycan moiety of the staphylococcal cell wall. The other major cell wall components, teichoic acid, lipoteichoic acid and protein A had no effect on the alternative pathway. Staphylococcal opsonization in human agammaglobulinemic serum (immunoglobulins .simeq. 0.5% of normal) was also mediated by peptidoglycan and involved activation of the alternative C pathway. Kinetic studies revealed that C activation, C3 fixation and opsonization proceeded at a slower rate via the alternative pathway than when both pathways were used. Optimal opsonization of staphylococci requires immunoglobulins and an intact classical pathway. The capacity of peptidoglycan to absorb heat-stable opsonins from immune serum and the ability of the eluted peptidoglycan antibody to promote phagocytosis of staphylococci by human polymorphonuclear leukocytes provide further evidence for the key role of peptidoglycan in the opsonic recognition of staphylococci by the human host. This may also be true for other gram-positive bacterial species.