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

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

VETERINARY PARASITOLOGY

ELSEVIER SCIENCE BV

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

0304-4017

Neospora caninum is an obligate intracellular protozoan parasite recognized as a major cause of abortion and economic losses to the cattle industry worldwide. Pregnancy failure seems to be associated with lack of innate defences at the maternal-fetal interface during infection. The aim of the present study was to define the gene expression of Toll-like receptors (TLRs) in pregnant heifers immunized with different vaccine formulations against N. caninum before mating and then challenged with live N. caninum on day 70 of gestation. TLR7 and TLR8 expression was upregulated in the placental caruncle of infected-pregnant heifers previously exposed to live N. caninum as immunogen. However, TLR7 and 8 expression in placenta and caruncle, as well as TLR3 and 9 in caruncle were upregulated when heifers were previously immunized with inactivated soluble whole antigens and recombinant NcSAG1, NcHSP20 and NcGRA7 proteins. These studies demonstrate that inactivated antigens induce key TLRs expression at the maternal-fetal interface, probably triggering strong inflammatory immune responses associated with abortion. On the other hand, previous infection with N. caninum seems to attenuate the innate immune response and restrict it to the maternal side. This finding represents novel information on how N. caninum vaccination and infection modulate TLRs expression at the placenta and fetal spleen, the possible role in the pregnancy outcome and transplacental transmission.