Maternal immune response in the placenta of sheep during recrudescence of natural congenital infection of Neospora caninum

• Published in: Veterinary parasitology 2020-09, Vol.285, p.109204-109204, Article 109204
• Main Authors: Gutiérrez-Expósito, Daniel, González-Warleta, Marta, Espinosa, Jose, Vallejo-García, Raquel, Castro-Hermida, Jose Antonio, Calvo, Carmen, Ferreras, María C., Pérez, Valentín, Benavides, Julio, Mezo, Mercedes
• Format: Article
• Language: English
• Subjects: Animals; antibodies; Antibodies, Protozoan - blood; cattle; Coccidiosis - immunology; Coccidiosis - veterinary; Cytokines; encephalitis; euthanasia; Female; fetal death; fetus; Immune response; Immunohistochemistry; Infectious Disease Transmission, Vertical; interleukin-10; interleukin-17; interleukin-18; interleukin-2; interleukin-4; macrophages; Neospora - immunology; Neospora caninum; neosporosis; parasites; pathogenesis; placenta; Placenta - immunology; Pregnancy; Recrudescence; Sheep; Sheep Diseases - immunology; Sheep Diseases - parasitology; veterinary parasitology; viability
• ISSN: 0304-4017; 1873-2550
• DOI: 10.1016/j.vetpar.2020.109204

[Display omitted] •Ovine neosporosis shows a highly efficient endogenous vertical transmission.•The severity of lesions was related to the time of gestation when recrudescence occurred.•The local immune response was more intense in those sheep carrying death fetuses.•High IL-17 levels could be related with the protection against vertical transmission. In order to gain further insight into the pathogenesis and transmission of ovine neosporosis, the serological response of 13 naturally infected pregnant sheep was monitored. All sheep were euthanized upon the detection of a sharp increase in the level of specific antibodies against N. caninum in order to study the maternal immune response after the recrudescence of a chronic infection. Ten sheep were euthanized between 84 and 118 days of gestation, whereas the three remaining and three control not infected, pregnant sheep were euthanized at 135 days of gestation after no sharp increase in antibodies was detected. Vertical transmission was confirmed in 11 sheep by detection of N. caninum-DNA in at least one fetus, confirming recrudescence. Not all of fetuses showed pathologic microscopic lesions, however, multifocal non-purulent encephalitis was the main finding. Furthermore, nine out of the 11 vertical transmission positive sheep had lesions in placentomes (mainly multifocal necrotic foci), and the parasite was detected in eight out of 11 placentas by PCR and/or immunohistochemestry. The placentomes from sheep that suffered recrudescence showed an increased number of T lymphocytes CD3+ (CD4/CD8