Effect of field capture on the measurement of cellular immune responses inwild ferrets (Mustela furo), vectors of bovine tuberculosis in New Zealand

Ferrets are recognised as significant wildlife vectors of bovine tuberculos is (TD) in New Zealand. Disease management strategies, such as the developm ent of a protective wildlife vaccine, could be assisted by the ability to m easure pertinent cellular immune responses among wild animals. In the prese nt study, we investigated whether it is possible to measure in vitro lympho cyte reactivity in wild-caught ferrets, and also determined levels of physi ological stress in these animals, and we compared these responses to those observed in laboratory-maintained domesticated ferrets. Over a 12-month per iod, 80 ferrets were live-captured from a Tb-endemic region (Otago, souther n New Zealand); cardiac blood was withdrawn on-site, and mononuclear cell c ultures were successfully established from 75 of these animals. Lymphocyte transformation (LT) responses to T cell and T/B cell mitogens (Concanavalin A [Con A] and pokeweed mitogen) were measured via uridine incorporation as say. The magnitude of these responses did not differ significantly between animals that had been captured in wire-framed cage traps and those captured using soft-jawed leg-hold traps. Levels of serum cortisol and glucose (as indicators of physiological and oxidative stress, respectively) were highes t in animals captured using leg-hold traps. In comparison to domesticated f errets, wild-caught ferrets had lower overall LT responses to Con A, but si gnificantly higher levels of serum cortisol. Finally, 10/80 animals capture d from the wild were severely diseased (Tb+), as evidenced by gross tubercu lous lesions at autopsy. Successful mononuclear cell cultures were establis hed from nine of these animals; LT responses to Con A were significantly lo wer in Tb+ ferrets than in either wild-caught/non-diseased (Tb-) or domesti cated ferrets. These results demonstrate that it is possible to measure cel lular immune responses from the blood of wild-caught ferrets, but that fiel d capture and disease status may have detrimental effects on in vitro T cel l function, possibly due to the influence of physiological stress. (C) Inra /Elsevier, Paris.