In vitro adhesion and invasion inhibition of Shigella dysenteriae, Shigella flexneri and Shigella sonnei clinical strains by human milk proteins.
BACKGROUND
Shigella is the etiological agent of shigellosis, a disease responsible for more than 500,000 deaths of children per year, in developing countries. These pathogens colonize the intestinal colon, invade, spreading to the other enterocytes. Breastfeeding plays a very important role in protecting infants from intestinal infections. Amongst milk compounds, glycosylated proteins prevent the adhesion of many enteropathogens in vitro. The aim of this work was to determine the effect of human milk proteins on the colonization potential of Shigella dysenteriae, S. flexneri and S. sonnei. To fulfill this purpose, pooled milk samples from five donors, were fractionated by gel filtration and affinity chromatography. Using tissue culture, the milk fractions obtained were tested in Shigella adhesion and invasion assays.


RESULTS
Our revealed showed that both adhesion and invasion of Shigella species were inhibited by low concentration of secretory immunoglobulin A, lactoferrin and free secretory component. This work also showed that, these proteins bind to superficial and whole-cell Shigella proteins.


CONCLUSIONS
Our findings suggest that human milk may act inhibiting adhesion and, consequently, invasion of Shigella, thereafter preventing shigellosis in infants.
Willer
Emerson da Motta
Eda M
Laboratório de Microbiologia, Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, 71910-900, Brasília-DF, Brazil. willer@unb.br
Lima
Renato de Lourenço
Rde L
Giugliano
Loreny Gimenes
LG
D000907:Antibodies, Bacterial / Q000494:pharmacology; D001422:Bacterial Adhesion / Q000187:drug effects*; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism; D002648:Child; D006367:HeLa Cells; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000276:immunology; D007781:Lactoferrin / Q000378:metabolism; D008894:Milk Proteins / Q000494:pharmacology*; D010504:Periodic Acid / Q000494:pharmacology; D012762:Shigella dysenteriae / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity*; D012763:Shigella flexneri / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity*; D012764:Shigella sonnei / Q000187:drug effects / Q000302:isolation & purification / Q000472:pathogenicity*
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D007071:Immunoglobulin A, Secretory; D008894:Milk Proteins; D010504:Periodic Acid; C009288:metaperiodate; D007781:Lactoferrin