Immunization with BLS-Stx2B chimera totally protects dams from early pregnancy loss induced by Shiga toxin type 2 (Stx2) and confers anti-Stx2 immunity to the offspring

FLAVIA SACERDOTI; MARÍA PILAR MEJÍAS; ANDREA CECILIA BURBALLA; ROMINA S ALVAREZ; MARÍA M AMARAL; MARINA S PALERMO; CRISTINA IBARRA

VACCINE

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2016 vol. 34 p. 4732 - 4737

0264-410X

Shiga toxin producing Escherichia coli (STEC) are bacterialpathogens involved in food-borne diseases. Shiga toxin (Stx) is the mainvirulence factor of STEC and is responsible for systemic complicationsincluding Hemolytic Uremic Syndrome (HUS). It has been previouslydemonstrated that Shiga toxin type 2 (Stx2) induces pregnancy loss inrats in early stage of pregnancy. The main purpose of this study was todetermine if an active immunization prevents Stx2 mediated pregnancy lossand confers passive protective immunity to the offspring. For thatpurpose Sprague Dawley female rats were immunized with the chimera basedon the enzyme lumazine synthase from Brucella spp. (BLS) and the Bsubunit of Shiga toxin 2 (Stx2B) named BLS-Stx2B. After immunizationfemales were mated with males. At day 8 of gestation, dams werechallenged intraperitoneally with a sublethal and abortifacient dose ofStx2. The immunization induced high anti-Stx2B-specific antibody titersin sera and most important, prevented pregnancy loss. Pups born andbreastfeed by immunized dams had high anti-Stx2B-specific antibody titersin sera. Fostering experiments indicated that passive protective immunityagainst Stx2 was transmitted through lactation. These results indicatethat immunization of adult female rats with BLS-Stx2B prevents Stx2-induced pregnancy loss and confers anti Stx2 protective immunity to theoffspring.