Perinatal immuno/inflammatory responses in the presence or absence of bovine fetal infection

Abstract

BackgroundIt is known that the bovine fetus can mount an immune and inflammatory reaction to infection, but it is not known whether there is a contemporaneous maternal response. Nor is it known whether the response of calves which die perinatally, with or without infection, differs from that of live perinates. Hence, the objective of this study was to determine if acute phase reactant and immunoglobulin concentrations differed between calves (and their dams) in three groups: live calves (CC; n = 21) and dead calves with (PM INF+; n = 22) or without (PM INF-; n = 89) in utero infection. In calf plasma, serum amyloid A, haptoglobin, immunoglobulins M, G1 and G2 and interleukin-6 were measured. In dam serum, SAA and Hp was measured and in amniotic and abomasal fluid, IL-6 was measured.ResultsLive calves had higher plasma concentrations of SAA and IL-6 than dead calves with (PM INF+) or without (PM INF-) in utero infection. Calves in the PM INF-, but not PM INF+ group, had higher Hp concentrations than calves in the CC group. Calves in the PM INF+ group had higher IgG1 concentrations than calves in the PM INF- and CC groups. Except for higher IgG1 and IgG2 concentrations, biomarker values did not differ significantly between dead calves with or without in utero infection. Live calves had higher IL-6 concentrations in abomasal fluid compared to PM INF- calves. There were no significant differences in blood biomarker concentrations between dams of the three groups of calves. Amniotic fluid IL-6 concentrations were higher from the dams of control calves than the dams of uninfected calves.ConclusionsDifferences in biomarkers (higher Hp and IgG1; lower SAA and IL-6) between perinatal mortalities and live perinates probably reflect differences between these two groups in age at sampling (SAA and IL-6) and in utero infection (IgG1). Out of the six analytes measured in calves, only IgG1 and IgG2 were biomarkers of (chronic) in utero infection.

Role of Infection and Immunity in Bovine Perinatal Mortality: Part 2. Fetomaternal Response to Infection and Novel Diagnostic Perspectives

“…However, increased plasma concentrations of fetal IL-6 were not detected in PM calves with infection [63]. Moreover, IL-6 concentrations in plasma and in abomasum fluid were higher in living compared to dead calves [63]. The probable reason for this was that all the dead calves in that study were infected early in pregnancy, not at calving, since only calves with fetal antibodies were examined.…”

“…As in humans, interleukin-6 should be a good biomarker of inflammation in the bovine fetus also. However, increased plasma concentrations of fetal IL-6 were not detected in PM calves with infection [63]. Moreover, IL-6 concentrations in plasma and in abomasum fluid were higher in living compared to dead calves [63].…”

“…In bacterial infection (detected at full term) in calves, IgM concentration in the precolostral sera was higher compared to other causes of death [100]. In PM cases, where infections (parasitic, viral, or bacterial) were diagnosed by the specific Ig in calves blood, concentrations of IgG 1 and IgG 2 , but not IgM, were significantly higher than in other causes of PM [63].…”

“…In cases of bacterial infection, high APPs as a response to infection in stillborn calves may be similar to that described as FIRS in human fetuses. When using nonspecific biomarkers like APP, it should be remembered that other conditions may influence the results, and if calves live several hours before sampling (after birth), the SAA concentration may be increased due to calving [63].…”

Investigation of bovine abortion and stillbirth/perinatal mortality - similar diagnostic challenges, different approaches

“…However, reliance on foetal serology alone may grossly underestimate foetal infection rates [30]. Recently, other biomarkers (acute phase proteins and non-pathogen specific immunoglobulins) have also been shown to be detectable in bovine foetal infection [31].…”