Changes in mononuclear immune cells during bovine pregnancy

Abstract

This study aimed to determine the differences in gene expression between mononuclear cells derived from peripheral blood and endometrium during pregnancy in cattle and to determine the proportion of mononuclear cells in the endometrium of pregnant and diestrous cows. Endometrial tissue and peripheral blood were collected from Day 34 ± 2 pregnant cows, and mononuclear cell populations were quantified and sorted (n = 5). The relative mRNA levels of inflammatory mediators was assessed by quantitative real time polymerase chain reaction. During pregnancy, the proportion of CD8+, CD4+, CD4+CD25− and CD4+CD25dim cells among mononuclear cells was greater in blood than endometrium, and cells positive for CD14 and CD68 expressed greater mRNA amounts of interleukin (IL) 6, CXCL8 and IL10 in endometrium compared with blood. Cells positive for γ/δ-T cell receptor expressed greater amounts of IL1A transcript in the endometrium than in blood of diestrous cows, CD4+CD25bright cells expressed more CTLA4 mRNA in the endometrium compared with blood of diestrous cows, and endometrial natural killer cells expressed greater CXCL8 mRNA compared with blood of pregnant and diestrous cows. The percentages of CD21+, NCR1+, CD8+, FoxP3+, CD3+ and CD68+ cells were greater in the endometrium of Day 35 pregnant cows compared with diestrous cows.

Adaptive changes in immunological, hematological and metabolic profiles of pregnant cows

“…Monitoring biochemical indicators in the blood of cows throughout various stages of pregnancy can provide valuable insights into their health status and reproductive performance. Some essential biochemical indicators that are commonly assessed during different periods of cow pregnancy (Alhussien et al, 2018;Rutigliano et al, 2022).…”

“…Similarly, progesterone plays a critical role in fertility, particularly in establishing and maintaining pregnancy. Studies with beef heifers and dairy cows have shown positive connections between higher concentrations of progesterone and improved immune functions immediately after conception (Velázquez et al, 2019;Leppo et al, 2022).…”

“…Endometrial luminal epithelial cells actively contribute to the immune response by producing pro-inflammatory factors like cytokines and chemokines. The endometrial tissues possess both local innate and adaptive response mechanisms, varying with the hormonal status during different reproductive phases (Zhelavskyi, 2021;Rutigliano et al, 2022).…”

“…This tolerance is facilitated by various immunological adaptations, including the suppression of certain immune responses that might otherwise recognize the fetus as foreign and mount an attack. This immune tolerance is crucial for a successful pregnancy and the prevention of miscarriage Leppo et al, 2021;Rutigliano et al, 2022).…”

Effects of parity and early pregnancy on peripheral blood leukocytes in dairy cattle

“…Expression of the anti-inflammatory cytokines, IL10, interleukin 4 (IL4), TGFB, and the enzyme IDO1 was also greater in blood leukocytes of pregnant versus cyclic cows (Yang et al, 2016; Mohapatra et al, 2020). The authors also observed that transcript abundance for interleukin 1 (IL1), interleukin 6 (IL6), interleukin 8 (IL8) and IL10 were greater in the endometrium compared with peripheral blood mononuclear cells (PBMC) (Rutigliano et al, 2022). Clearly, the establishment of pregnancy involves regulation of immune cell types to direct migration, proliferation, apoptosis, and cytokine secretion in the uterus and circulation.…”