Submitted to: The Veterinary Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/2/2008
Publication Date: 11/20/2008
Citation: Rinaldi, M., Moroni, P., Paape, M.J., Bannerman, D.D. 2008. Differential alterations in the ability of bovine neutrophils to generate extracellular and intracellular reactive oxygen species during the periparturient period. The Veterinary Journal. 178:208-213. Interpretive Summary: Neutrophil bactericidal activity is a critical component of the innate immune defense against pathogenic bacteria, the latter of which are responsible for an array of cattle diseases, including mastitis. The bactericidal activity of neutrophils is mediated, in part, by the generation of toxic molecules known as reactive oxygen species (ROS). It is well known that deficient generation of ROS enhances susceptibility to uncontrollable infection. It has been postulated that decreased ROS production immediately after calving contributes to a state of immunosuppression and the corresponding increase in the incidence of mastitis and other diseases associated with this period. The current study demonstrates that although extracellular ROS production does decrease after calving, intracellular ROS production increases. Because intracellular, but not extracellular ROS, are critical for neutrophil-mediated killing of bacteria, these data suggest that the incidence of disease associated with calving cannot be directly attributed to impairment of ROS production
Technical Abstract: The periparturient period of a dairy cow is associated with increased incidence and/or severity of certain infectious diseases, including mastitis. It is believed that the heightened physiological demands of calving and initiation of milk production contribute to a state of immunosuppression during this period. Previous studies have indicated that neutrophil production of reactive oxygen species (ROS), which is a critical element of the host innate immune response to bacterial infection, is impaired in the 1-2 week period following calving. However, whether there is comprehensive inhibition of ROS production or selective inhibition of particular ROS remains unknown. The present study provides evidence that neutrophils isolated from cows (n = 20) after calving have an increased capacity to generate intracellular ROS and an impaired ability to release extracellular superoxide anion and hydrogen peroxide.