Free secretory component and lactoferrin of human milk inhibit the adhesion of enterotoxigenic Escherichia coli.
The non-immunoglobulin component of human milk responsible for the inhibition of Escherichia coli cell adhesion (haemagglutination) mediated by colonisation factor antigen 1 (CFA1) was determined by chromatographic fractionation of human whey proteins with Sephadex G-200, DEAE cellulose and heparin-sepharose. Pure free secretory component (fSC) and pure lactoferrin (Lf) were isolated and both compounds inhibited the haemagglutination induced by E. coli CFA1+. The lowest concentrations of purified fSC and Lf able to inhibit the haemagglutination induced by E. coli strain TR50/3 CFA1+ were 0.06 mg/ml and 0.1 mg/ml respectively. Commercially available lactoferrin from human milk and transferrin from human serum, which has a great structural analogy to lactoferrin, also inhibited the haemagglutination. The lowest concentrations of the commercial lactoferrin and transferrin able to inhibit the haemagglutination induced by E. coli TR50/3 CFA1+ were 0.03 mg/ml and 0.4 mg/ml, respectively. These results indicate that fSC and Lf may be important non-specific defence factors against enterotoxigenic E. coli infections.
Giugliano
L G
LG
Departamento de Biologia Celular, Universidade de Brasilia, Brazil.
Ribeiro
S T
ST
Vainstein
M H
MH
Ulhoa
C J
CJ
D001422:Bacterial Adhesion / Q000187:drug effects*; D002848:Chromatography, DEAE-Cellulose; D002850:Chromatography, Gel; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004768:Enterotoxins / Q000096:biosynthesis; D004926:Escherichia coli / Q000187:drug effects / Q000472:pathogenicity*; D006384:Hemagglutination / Q000187:drug effects; D006801:Humans; D007781:Lactoferrin / Q000302:isolation & purification / Q000494:pharmacology*; D008895:Milk, Human / Q000737:chemistry* / Q000276:immunology; D012635:Secretory Component / Q000302:isolation & purification / Q000494:pharmacology*; D016622:Silver Staining; D014168:Transferrin / Q000494:pharmacology
D004768:Enterotoxins; D012635:Secretory Component; D014168:Transferrin; D007781:Lactoferrin