title: Protection against abortion linked to gamma interferon production in pregnant dairy cows naturally infected with Neospora caninum.
abstract: Many immunological aspects of pregnancy, such as the role played by gamma interferon (IFN-gamma) in abortion, are not well understood. Neospora caninum is an intracellular protozoan considered to be among the main causes of abortion in cattle worldwide. The present study analyzes the interaction between IFN-gamma production and N. caninum infection in naturally infected pregnant cows. Data were obtained from 126 pregnant cows: 86 seropositive and 40 seronegative for the parasite. Pregnancy diagnosis and blood sample collection were performed on days 40, 90, 120, 150, 180 and 210 post-insemination or until the time of abortion detection. Plasma was tested for antibodies against N. caninum and IFN-gamma. Interferon-gamma was detected at some point along the pregnancy in 16 (19%) of the 86 Neospora-seropositive cows yet was undetectable in the 40 seronegative animals. Of the 126 pregnancies examined, 22 (17.5%) ended in abortion. Abortion occurred in 24.4% of seropositive cows (21/86) and in 2.5% of seronegative animals (1/40). Significant (P<0.0001) interaction was observed between Neospora-seropositivity and IFN-gamma production. Based on the odds ratio, the risk of abortion was 15.6 times higher in seropositive cows not producing IFN-gamma than in seronegative animals, whereas neosporosis had no effect in seropositive cows with IFN-gamma production. A significant (P=0.001) negative effect of IFN-gamma production on the Neospora titer was furthermore observed in the 65 non-aborting seropositive animals. These results indicate that IFN-gamma production affords protection against abortion in Neospora-infected cows and also point to a reduced humoral immune response to N. caninum during gestation in cows producing IFN-gamma.
authors.affiliation: Department of Animal Production, University of Lleida, Lleida, Spain. flopez@prodan.udl.es
authors.forename: F
authors.initials: F
authors.lastname: López-Gatius
authors.forename: S
authors.initials: S
authors.lastname: Almería
authors.forename: G
authors.initials: G
authors.lastname: Donofrio
authors.forename: C
authors.initials: C
authors.lastname: Nogareda
authors.forename: I
authors.initials: I
authors.lastname: García-Ispierto
authors.forename: G
authors.initials: G
authors.lastname: Bech-Sàbat
authors.forename: P
authors.initials: P
authors.lastname: Santolaria
authors.forename: J L
authors.initials: JL
authors.lastname: Yániz
authors.forename: M
authors.initials: M
authors.lastname: Pabón
authors.forename: N M
authors.initials: NM
authors.lastname: de Sousa
authors.forename: J F
authors.initials: JF
authors.lastname: Beckers
mesh_terms: D000028:Abortion, Induced / Q000662:veterinary; D000034:Abortion, Veterinary / Q000276:immunology*; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology*; D003048:Coccidiosis / Q000276:immunology / Q000662:veterinary*; D003612:Dairying; D005260:Female; D007371:Interferon-gamma / Q000097:blood / Q000378:metabolism*; D018688:Neospora / Q000276:immunology*; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000276:immunology*; D013997:Time Factors
chemical_list: D000913:Antibodies, Protozoan; D007371:Interferon-gamma