Binding of bovine lactoferrin to Streptococcus agalactiae

Bovine lactoferrin is an iron-binding protein present in mammary gland secretions. The exposure of Streptococcus agalactiae to bovine lactoferrin resulted in the binding of this protein to all the 12 strains of bovine origin tested, and also, although to a lesser degree, to the five tested strains of human origin. The interaction of lactoferrin with one high-binding bovine strain (24/60, the prototype NT/X strain) was studied. Binding was time-dependent, dose-dependent, and saturable. The binding of lactoferrin was slightly affected by cultivation conditions, and appeared to be heat-stable. The binding of biotinylated lactoferrin was inhibited by unlabelled lactoferrin but not by bovine serum albumin.