Immunization with inactivated antigens of Neospora caninum induces tolllike receptors 3, 7, 8 and 9 in maternal-fetal interface of infected pregnant heifers

MARIN, M.S.; PÉREZ S.E.; COBO E.; MARIN, M.S.; PÉREZ S.E.; COBO E.; QUINTANA S.; CANTÓN G.; ODEÓN A; QUINTANA S.; CANTÓN G.; ODEÓN A; HECKER Y.P.; LEUNDA M.R.; MOORE D.P.; HECKER Y.P.; LEUNDA M.R.; MOORE D.P.

VETERINARY PARASITOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 243 p. 12 - 17

0304-4017

Neospora caninum is an obligate parasite and a major cause of abortion in cattle. Pregnancy failures appear to beassociated with weak innate defences on the maternal-fetal interface during infection with N. caninum. Herein,we studied the gene expression of Toll-like receptors (TLRs) in pregnant heifers immunized with differentvaccine formulations against N. caninum before mating and then challenged the heifers with live N. caninum onday 70 of gestation. TLR7 and TLR8 expression was upregulated in the placental caruncle of infected-pregnantheifers previously exposed to live N. caninum as immunogen. However, TLR7 and 8 expression in both placentaand caruncle as well as, TLR3 and 9 expression in caruncle were upregulated when heifers were previouslyimmunized with inactivated soluble whole antigens and recombinant NcSAG1, NcHSP20 and NcGRA7 proteins.All dams were carrying viable fetuses when they were culled at day 104 of gestation. Upregulation of TLR7 andIFNγ expression was detected in fetal spleen when their mothers where previously vaccinated with solubleantigens and recombinant NcSAG1, NcHSP20 and NcGRA7 proteins. These studies demonstrate that soluble orrecombinant NcSAG1, NcHSP20 and NcGRA7 antigens induce key TLRs expression at the maternal-fetal interface,probably triggering damaging inflammatory cellular immune responses associated with abortion. Previousinfection with N. caninum seems to attenuate the innate immune response at the maternal-fetal interface, whichcould favour pregnancy maintenance and perpetuation of the disease. This finding represents novel informationon how N. caninum vaccination and infection modulate TLRs expression at the placenta and fetal spleen, thepossible role in the pregnancy outcomes and transplacental transmission of the protozoa.