Leukocyte Coping Capacity: A Novel Technique for Measuring the Stress Response in Vertebrates

Abstract

Methods used to quantify the stress response in animals are vital tools in many areas of biology. Here we describe a new method of measuring the stress response, which provides rapid results and can be used in the field or laboratory. After a stressful event, we measure the capacity of circulating leukocytes to produce a respiratory burst in vitro in response to challenge by phorbol myristate acetate (PMA). During the respiratory burst leukocytes produce oxygen free radicals, and the level of production can be measured directly as chemiluminescence. When in vitro PMA‐stimulated whole blood chemiluminescence is measured directly after a stressful event, we define the response as the leukocyte coping capacity (LCC). In an experiment badgers (Meles meles), which were caught as part of an on‐going population study, were either transported to a central site prior to blood sampling or blood was collected at their site of capture. Transported animals had a significantly lower LCC and showed changes in leukocyte composition that were indicative of stress. We conclude that the stress of transport reduced LCC in badgers and that LCC serves as a quantitative measure of stress. Potential applications of this method are discussed.

Leukocyte reactivity as an objective means of quantifying mental loading during ergonomic evaluation

“…This is an indicator of the leukocytes' ability to produce a respiratory burst [22]. LCC is defined as the response of leukocytes (mainly neutrophils) to challenge, in this case by PMA or also by fMLP…”

“…The cells are stimulated in vitro with PMA and the superoxide producing capacity of the cells is measured in real time. As leukocytes release reactive oxygen species in response to stress [22], the stimulation allows us to evaluate the capacity that the cells have to produce further reactive oxygen species. This takes into account the exposure to other stress mediators and makes the test sensitive to true stress; the reactivity of the cells is not altered by deliberate manipulation.…”

“…More recently, chemiluminescent assay of PMA-induced ROS production by leukocytes has been shown to provide quantitative links between psychological anxiety and immune-competency [22,23,24]. The Leukocyte Coping Capacity (LCC) technique involves measuring the ability of leukocytes to produce a respiratory burst following chemical challenge, assayed in terms of Reactive Oxygen Species (ROS) and calibrated through the emission of photons via their interaction with Luminol [22].…”

“…The Leukocyte Coping Capacity (LCC) technique involves measuring the ability of leukocytes to produce a respiratory burst following chemical challenge, assayed in terms of Reactive Oxygen Species (ROS) and calibrated through the emission of photons via their interaction with Luminol [22].…”

Leukocyte responsiveness, a quantitative assay for subjective mental workload

“…Stress has been shown to influence the number, distribution and activation state of neutrophils in the blood in a rapid and reversible manner (Dhabhar et al, 1995;Goebel and Mills, 2000;McLaren et al, 2003;Mian et al, 2003;Shelton-Rayner et al, 2011. When compared to the stressor paradigm utilised during this research, all previous examples utilised stressors that were of far greater duration and/or intensity.…”