Effects of a streptococcal lipoteichoic acid on complement activation in vitro.
This study describes activation of serum complement by lipoteichoic acid (LTA) from Streptococcus mutans OMZ 176, while in solution. Serum from 16 healthy students was taken. Test samples were incubated with increasing doses (1-5,000 micrograms/ml) of LTA or lipopolysaccharide (LPS) from Escherichia coli 0111:B4 for 1 h at 37 degrees C; then assayed for degradation of C3, C4 or factor B by crossed immunoelectrophoresis. Each preparation caused a significant (p < 0.05) dose-dependent conversion of C3. The response curves obtained were not statistically different. LPS was a stronger activator of the alternative pathway than LTA, as judged from analysis of C3 degradation in the presence of Mg2+/EGTA, and from their effects on factor B cleavage. LTA caused, however, pronounced alterations in the shape of C4 precipitation in the gels. Functional (hemolytic) assays showed that, when tested at 200 micrograms/ml, LTA and LPS triggered significant (p < 0.05) consumptions of both classical and alternative pathway proteins. LPS was a significantly (p < 0.05) stronger activator than LTA. Apparently, the C3 degradation found for this LTA involved the alternative pathway to a small extent; thus some other mechanism of fluid-phase C3 cleavage seemed also to be operative.
Monefeldt
K
K
Department of Microbiology, Dental Faculty, University of Oslo, Norway.
Tollefsen
T
T
D003167:Complement Activation / Q000187:drug effects*; D015932:Complement C3c / Q000032:analysis; D003181:Complement C4 / Q000032:analysis; D015935:Complement C4b; D011415:Complement Factor B / Q000032:analysis; D015941:Complement Hemolytic Activity Assay; D003170:Complement Pathway, Alternative / Q000187:drug effects; D003171:Complement Pathway, Classical / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007074:Immunoglobulin G / Q000032:analysis; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D010446:Peptide Fragments; D013295:Streptococcus mutans; D013682:Teichoic Acids / Q000008:administration & dosage / Q000494:pharmacology*
D003181:Complement C4; D007074:Immunoglobulin G; D008070:Lipopolysaccharides; D010446:Peptide Fragments; D013682:Teichoic Acids; C033860:complement C4c; C009900:lipoteichoic acid; D015932:Complement C3c; D015935:Complement C4b; D011415:Complement Factor B