The Journal of Medical Microbiology, Vol 36, Issue 3 177-183, Copyright © 1992 by Society for General Microbiology

JOURNAL ARTICLE

Identification of a human lactoferrin-binding protein in Staphylococcus aureus

A. S. Naidu, M. Andersson and A. Forsgren
Department of Medical Microbiology, University of Lund, Malmo General Hospital, Sweden.

Human lactoferrin (HLf) is an iron-binding protein with antimicrobial activity that is present in high concentrations in milk and various exocrine secretions. HLf is also an acute-phase protein secreted by polymorphonuclear leucocytes, and its binding to a large number of clinical isolates of Staphylococcus aureus has been described recently from our laboratory. We have now characterised the HLf-staphylococcal interaction in S. aureus strain MAS-89. The binding of 125I-HLf to strain MAS-89 reached saturation in less than 90 min and was maximal between pH 4 and 9. Unlabelled HLf displaced 125I-HLf binding. Various plasma and subepithelial matrix proteins, such as IgG, fibrinogen, fibronectin, collagen and laminin, which are known to interact specifically with S. aureus, did not interfere with HLf binding. A Scatchard plot was non-linear; this implied a low affinity (1.55 x 10(7) L/mol) and a high affinity (2.70 x 10(8) L/mol) binding mechanism. We estimated that there were c. 5700 HLf binding sites/cell. The staphylococcal HLf-binding protein (HLf-BP) was partially susceptible to proteolytic enzymes or periodate treatment and was resistant to glycosidases. An active HLf-BP with an apparent Mr of c. 450 Kda was isolated from strain MAS-89 cell lysate by ion-exchange chromatography on Q-sepharose. In SDS-PAGE, the reduced HLf-BP was resolved into two components of 67 and 62 Kda. The two components demonstrated a positive reaction with HLf-HRPO in a Western blot. These data establish that there is a specific receptor for HLf in S. aureus.

This article has been cited by other articles:

				M. E. Shirtliff and J. T. Mader Acute Septic Arthritis Clin. Microbiol. Rev., October 1, 2002; 15(4): 527 - 544. [Abstract] [Full Text] [PDF]

				M. S. Diarra, D. Petitclerc, and P. Lacasse Response of Staphylococcus aureus Isolates from Bovine Mastitis to Exogenous Iron Sources J Dairy Sci, September 1, 2002; 85(9): 2141 - 2148. [Abstract] [Full Text] [PDF]

				G. P. Jarosik and C. B. Land Identification of a Human Lactoferrin-Binding Protein in Gardnerella vaginalis Infect. Immun., June 1, 2000; 68(6): 3443 - 3447. [Abstract] [Full Text] [PDF]

				S. Hammerschmidt, G. Bethe, P. H. Remane, and G. S. Chhatwal Identification of Pneumococcal Surface Protein A as a Lactoferrin-Binding Protein of Streptococcus pneumoniae Infect. Immun., April 1, 1999; 67(4): 1683 - 1687. [Abstract] [Full Text] [PDF]

				B. Modun and P. Williams The Staphylococcal Transferrin-Binding Protein Is a Cell Wall Glyceraldehyde-3-Phosphate Dehydrogenase Infect. Immun., March 1, 1999; 67(3): 1086 - 1092. [Abstract] [Full Text] [PDF]