Avaliação da resposta imune celular de ovelhas ao desafio por Staphylococcus spp.

Abstract

The aim of this study was to challenge blood polymorphonuclear leukocytes (PMNL) from sheep with Staphylococcus species (S. aureus, S. haemolyticus, S. chromogenes, S. simulans, S. xylosus, S. sciuri eS. Devriesi) isolated from different ecological niches of sheep. For this, blood was collected from 14 Santa Inês sheep (7 primiparous and 7 multiparous) and 14 Lacaune sheep (7 primiparous and 7 multiparous). We evaluated the viability, the intracellular production of reactive oxygen species (ROS) of PMNL, and the ability to resist opsonized and non-opsonized phagocytosis of the different Staphylococcusspp isolates. by flow cytometry. Initially, we observed the possible differences in viability, phagocytic responses and intracellular production of reactive oxygen species by blood PMNL from Santa Inês and Lacaune sheep, primiparous and multiparous, challenged with a Staphylococcus aureus isolate. Subsequently, we evaluated the escape behavior of the immune defenses of aureus and non-aureus staphylococcus isolates, considering phagocytosis and the inhibition of ROS production by PMNL from the blood of Santa Inês sheep.We observed a higher intensity of phagocytosis of S. aureus by PMNL from multiparous ewes and no effect of parity on the functionality of blood PMNL was found. The phagocytosis behavior was different between the Santa Inês and Lacaune breeds and the antibody mediated S. aureus opsonization was associated with a lower intensity of phagocytosis by primiparous sheep. The PMNL of Lacaune ewes led to the highest geometric mean fluorescence intensity (GMFI) of intracellular ROS production when stimulated with S. aureus, suggesting that greater microbicidal activity and / or inflammation could be triggered in these ewes. Our results show that multiparous sheep phagocytized more than primiparous ewes and that phagocytized more non-aureus Staphylococcus (ANS) than S. aureus. Among SNA isolates, Staphylococcus chromogenes was the one with the highest geometric mean fluorescence intensity (GMFI) of phagocytosis. All species, except S. devriesi, presented a higher percentage of opsonized phagocytosis than non-opsonized. For the first time, we demonstrated that multiparous ewes phagocytosed more than primiparous ewes, in addition to observing a higher intensity of phagocytosis of S. chromogenes by sheep PMNLs. Thus, our study provides new insights into the functionality of PMNLs in primiparous and multiparous ewes, which could affect their health, along with other possible variables such as herd management and health conditions.