Inhibition of adhesion of S-fimbriated Escherichia coli to buccal epithelial cells by human milk fat globule membrane components: a novel aspect of the protective function of mucins in the nonimmunoglobulin fraction

Abstract

We investigated the presence of factors in human milk that inhibit invasion of pathogenic bacteria. The effect of human milk fat globule membrane (HMFGM) components on adhesion of cloned S-fimbriated Escherichia coli to human buccal epithelial cells was analyzed. S fimbriae are a common feature of E. coli strains causing sepsis and meningitis in newborns and are bound to epithelia via sialyl-(a-2-3)galactoside structures. Human milk fat globules (HMFG) could be agglutinated by the above-mentioned bacteria. Agglutination could be inhibited by fetuin, human glycophorin, and al-acid glycoprotein. In addition, pretreatment of HMFG with Vibrio chokrae neuraminidase markedly reduced bacterium-induced agglutinations, indicating the involvement of neuraminic acid-containing glycoproteins. In contrast, lipid droplets of infant formula or artificial lipid emulsions (Intralipid) could not be agglutinated. HMFG were present in stools of breast-fed neonates as shown by indirect immunofluorescence staining with a monoclonal antibody directed against carbohydrate residues present on HMFGM. These HMFG could be agglutinated by bacteria. HMFG inhibited E. coli adhesion to buccal epithelial cells. To further characterize relevant E. coli binding structures, HMFGM components were separated by gel chromatography. The mucin fraction showed the most pronounced inhibitory effect on adhesion of S-fimbriated E. coli to human buccal epithelial cells. Our data suggest that HMFG inhibit bacterial adhesion in the entire intestine and thereby may provide protection against bacterial infection.

Inhibition of Helicobacter pylori sialic acid-specific haemagglutination by human gastrointestinal mucins and milk glycoproteins

“…Roles of mucin-like components from milk in the prevention of bacterial adhesion have been reported for several pathogens [25,26]. In our studies, MFGM preparation showed a high inhibitory potency for H. pylori-induced haemagglutination.…”

Structure, evolution, and biology of the MUC4 mucin

“…The role of MUC4 in milk still remains poorly characterized. Nevertheless, MUC1 has been shown to bind to rotavirus and to enteropathogenic strains of Escherichia coli and is considered as an important component of innate immunity (57,58). Mucins produced by breast milk also inhibit poxvirus activity by aggregating the poxviruses before their entry into host cells (59).…”

Male Mammary Fistula Complicating Senescent Gynecomastia

“…Cigarette smoking also causes a reduction in prolactin secretion by increasing hypothalamic dopamine secretion. Prolactin is important for the production of human milk fat globule membrane, which is an essential antibacterial component of milk (8). Smoking has recently been linked with the production of interleukin-8 (IL-8), an important cytokine and mediator of the inflammatory response (9).…”