Experimental Neospora Caninum Infection in Pregnant Dairy Heifers Raises Concentrations of Pregnancy‐Associated Glycoproteins 1 and 2 in Foetal Fluids

Abstract

Plasma concentrations of PAG-1 are used for pregnancy diagnosis and as a marker of placental/foetal well-being, while those of PAG-2 may be an indicator of abortion risk in Neospora caninum-infected cows. Studies have shown that N. caninum infection modifies PAG-1 and PAG-2 patterns in maternal blood plasma. However, no prior work has examined the effects of N. caninum infection on concentrations of PAGs in foetal fluids. In this study, PAG-1, PAG-2 and pH levels were determined in the amniotic and allantoic fluids of foetuses collected at 152 days of gestation from control uninfected dams and from dams experimentally infected with N. caninum on Day 110 of gestation. Foetal fluids from infected foetuses had significantly higher PAG-2 concentrations (p = 0.026) and pH values (p = 0.02) than fluids from non-infected foetuses. In infected foetuses, significantly higher concentrations of PAG-1 (p < 0.001) and PAG-2 (p < 0.001) were detected in fluid samples showing antibodies against N. caninum than those without antibodies. Moreover, pH values were significantly higher (p = 0.011) in foetal fluid samples with antibodies than in samples from non-infected foetuses. In conclusion, this is the first report on the effect of N. caninum infection on PAG levels in foetal fluids. Our results indicate that following the experimental infection of dams with N. caninum on Day 110 of gestation, foetal fluids collected from the infected foetuses of these dams featured higher PAG-1 and PAG-2 levels and pH values than fluids from non-infected controls, provided that the samples tested showed the presence of antibodies. The clinical implications of these findings are that following infection with N. caninum, most cows will experience some level of placental damage and that this injury correlates with foetal fluid PAG levels and pH.

Using Pregnancy-Associated Glycoproteins (PAGs) to Improve Reproductive Management: From Dairy Cows to Other Dairy Livestock

“…Despite the fact that there have been various works on bovine animals [ 120 , 121 , 122 , 123 ] in which PAGs were measured using also antibodies raised against PAG-2, to our knowledge, only two works exist in which this method was reported for buffalo species [ 124 , 125 ]. The results of these works showed that the threshold value of 1.0 ng/mL was not reached before day 40 post-AI, although significant differences between pregnant and non-pregnant buffaloes were found starting from Day 28 post-AI.…”

Investigation of PAG2 mRNA Expression in Water Buffalo Peripheral Blood Mononuclear Cells and Polymorphonuclear Leukocytes from Maternal Blood at the Peri-Implantation Period

“…To our knowledge, this is the first work in which the plasma concentration of PAG molecules during the gestation period was measured using antibodies raised against PAG-2 in buffalo, although, there are various works in which this method has been reported for bovine species [31,32,34,35]. Although significant differences were found starting from Day 28 post AI, our results show that the threshold value for pregnancy diagnosis (1.0 ng/mL) was only reached at Day 40 post AI, as previously reported for bovine species in [31,32,34,35]. Therefore, this work confirmed that in buffalo as well, the pre-eminent PAG radioimmunoassay method to diagnose pregnancy utilizes antibodies raised against PAG-1, as reported in our previous work [26,29,30].…”

“…The bovine PAG-2 radioimmunoassay used has been described recently in [31,34,38]. Briefly, PAG-2 was purified according to the method detailed by Beckers et al [39].…”

“…Water buffalo PAG-1 concentrations can be detected in the blood of pregnant females around Day 28 and 30 of gestation by radioimmunoassay (RIA) [15,28,29,30]. Very recently, a new approach was described in which an antiserum was raised against boPAG-2 allowing PAG molecules to be detected in maternal blood [31,32,33,34,35] in bovine species. For the buffalo species, eleven PAG molecules from group-I were purified and characterized from water buffalo placenta (wbPAG) [15,28,29,30] while 19 different complementary DNA (cDNA) of PAG genes were identified in this species [36].…”

Neosporosis bovina en Argentina: a 25 años del primer reporte en el país

“…Se especula que algunas funciones placentarias, en preñeces de razas cruza, se cumplen de manera más eficiente probablemente debido al aumento en la expresión de glicoproteínas asociadas a la preñez (pregnancy associated-glycoproteins, PAG). En hembras que abortaron se detectó una disminución considerable en su expresión (López-Gatius et al, 2007;Mur-Novales et al, 2016;Serrano-Pérez et al, 2014, 2016Wooding et al, 2005).…”