SHIGA TOXIN DURING PREGNANCY AND BREASTFEEDING: CAN HUMAN MILK PROTECT CHILDREN FROM TYPICAL HUS?

SACERDOTI, FLAVIA

Puerto Varas

Congreso; Latin Amerciam Symposium for Maternal Fetal Interaction and Placenta; 2017

Shiga toxin type 2 (Stx2) is a virulence factor of Shiga toxin producing E.coli (STEC) and is responsible for Haemolytic Uremic Syndrome develop-ment. We have previously demonstrated that an active immunizationagainst Stx2 protects rats from early pregnancy loss mediated by the toxinand also protect pups through breastfeeding. We propose human milk canprotect the breastfeed newborn from STEC infections through immuneand/or non-immune components. The aim of this work was to evaluate ifantibodies from human milk can recognize and inhibit Stx2 and othervirulence factor of STEC. For that purpose human milks from healthy do-nors were collected at the Hospital Alejandro Posadas (Buenos Aires,Argentina). Milks were conserved at -20C until used. Samples weredefatted by centrifugation and the liquid phase was used. In order toanalyse the presence of specific antibodies against STEC O157:H7 (n 1⁄4 24)and the STEC virulence factor EspB (n 1⁄4 8), ELISA and Western blot assayswere performed, respectively. In order to analyse if human milk canneutralize Stx2, neutralization assays on Vero cell were performed. Theresults indicate that 50 % of analysed human milks had immunoglobulinsagainst O157:H7 E. coli, although no specific anti EspB antibodies weredetected in the analysed samples. Moreover human milks showed no ca-pacity to neutralize in vitro Stx2. Our data indicate that human milk canrecognize STEC O157:H7 but does not neutralize Stx nor identify EspB.Further analysis will be performed to evaluate if other non-immunecomponents of human milk (lipids or cells) can mediate protection againstStx2 through breastfeeding.