A previous work indicated that β-estradiol binds to human fibrinogen with a Kd = 1.55×10−7 M [28].
Taken together, these data suggest a greater role of the fibrinogen-binding protein FbsB as compared to FbsA in the binding ability to human fibrinogen of CC17 GBS strains.
Thus, depending on the genetic background of the GBS strains, several fbs regulatory circuits may be defined and may account for the differences in the relative implication of fbs genes in GBS binding-ability to human fibrinogen.
An alternative function for the S. aureus phage encoded autolysins is suggested by recent work on bacteriophage-encoded autolysins in Streptococcus mitis, which demonstrated their role in binding to human platelets through interaction with fibrinogen [37].
We here studied the molecular events involved in the fibrinogen-binding ability of CC17 strains that were previously shown to bind significantly more strongly to human fibrinogen than strains of other lineages that constitute the species [17].
Interestingly, immunohistochemistry for human fibrinogen indicated the ubiquitous existence of a protein with high affinity to human fibrinogen antibody in Botryllus compartment cells, the derivatives of the signet-ring cell lineage [36], [37].
Fibrinogen was measured using the BNII nephelometer (N Antiserum to Human Fibrinogen; Dade Behring Inc, Deerfield, Illinois, USA).
CRP and fibrinogen were measured using the BNII nephelometer (N High-Sensitivity CRP and N Antiserum to Human Fibrinogen; Dade Behring).
