Bacteriostasis of Escherichia coli by bovine lactoferrin, transferrin and immunoglobulins (IgG1, IgG2, IgM) acting alone or in combination.
The effect on Escherichia coli strain B117 of bovine lactoferrin (LF), transferrin (Tr) and immunoglobulins (Ig), acting alone or in combination, was investigated in vitro. IgG1 and IgM, which, in contrast to IgG2 possessed a marked antibody activity, as assessed by enzyme-linked immunosorbent assay, induced the appearance of microcolonies in suspension, a phenomenon which could lead to misleading interpretations in the absence of sonic treatment, but none of these three isotypes influenced bacterial growth. Both LF and Tr promoted a strong inhibition of bacteria without requirement for antibodies. After a short period of growth, the multiplication of bacteria was almost completely prevented by the iron-binding proteins acting alone. A significant (p less than 0.02) but moderate (0.5 less than log10) further growth reduction was obtained when Ig of either class was added to Tr, while addition of Ig to LF revealed no significant cooperative effect. All of 11 strains of E. coli isolated from bovine mastitis were sensitive to LF action in the absence of Ig. It therefore appeared that antibodies were not required for iron-binding proteins to exert a potent bacteriostatic effect on mastitis isolates of E. coli.
D000818:Animals; D002417:Cattle; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development* / Q000276:immunology; D005260:Female; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007774:Lactation; D007781:Lactoferrin / Q000302:isolation & purification / Q000494:pharmacology*; D007782:Lactoglobulins / Q000494:pharmacology*; D008321:Mammary Glands, Animal / Q000378:metabolism; D011247:Pregnancy; D014168:Transferrin / Q000302:isolation & purification / Q000494:pharmacology*
D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007782:Lactoglobulins; D014168:Transferrin; D007781:Lactoferrin