Expressão de PD-1 e CTLA-4 em linfócitos T e sua relação com o período periparturiente e citologia endometrial no periodo pós-parto em vacas leiteiras

Abstract

The present study aimed to evaluate the expression of PD-1 and CTLA-4 in blood T lymphocytes during the periparturient period and its relationship with uterine health, determined by endometrial cytology, and serum concentrations of β-hydroxybutyrate (BHB) and fatty acids. non-esterified (NEFA), indicators of negative energy balance. For this, peripheral blood was collected from 26 dairy cows 14 days before calving (T-14), at calving (T0) and 30 days postpartum (T30) to determine the expression of PD-1 and CTLA- 4 in blood T lymphocytes by flow cytometry and on days T0, 10 postpartum (T10), and T30 for obtaining serum and serum determination of NEFA, BHB and the acute phase protein haptoglobin. Endometrial cytology was performed at T10, 20 days postpartum (T20) and T30. Our findings suggest that immune checkpoints play a fundamental role in immunological tolerance during bovine pregnancy, which, on the other hand, if highly expressed in T lymphocytes, can inhibit the immune response in such a way that leads to negative implications for uterine health. Thus, the present study represents an initial step that opens the way for the development of new therapeutic alternatives directed by the host with the objective of increasing the resistance of dairy cattle to infections in this critical period of the life of these animals.