Avaliação funcional de macrófagos lácteos em vacas leiteiras infectadas naturalmente pelo vírus da leucemia bovina.

Abstract

The implications of the bovine leukemia virus (VLB) on the innate and adaptive immune response have been extensively investigated, however, its effects on the mammary gland immunity need further investigation. In this sense, the present study investigated the viability, phagocytic capacity and intracellular production of reactive oxygen species (ROS) by macrophages and their viability in milk samples from cows naturally infected with VLB with or without persistent lymphocytosis (PL). Milk samples from VLB serologically positive cows showing PL showed a higher percentage of macrophages (CD14 +) compared to VLB seronegative cows. A higher percentage of dairy macrophages was identified in samples from animals infected with VLB showing PL when compared to samples from AL animals. The percentage of milk macrophages that phagocytized S. aureus in seronegative animals was higher in dairy cows infected with AL VLB. The percentage of milk macrophages that produced ROS and the intensity of phagocytosis did not differ between groups. The animals infected with the leukemic VLB and with LP had a higher percentage of viable dairy macrophages, while healthy animals had a higher percentage of apoptotic dairy macrophages than animals infected with the leukemic VLB and with LP. Thus, the present study provides important information about the implications of BLV infections in the mammary gland, impacting the functionality of milk macrophages in animals infected with BLV, especially those with PL. The results obtained provide new information regarding the implications on the mammary gland of infections with BLV, mainly regarding the functionality of macrophages in animals with persistent lymphocytosis.