The immune system is very important in an individual’s defense against pathogenic microorganisms that live in one’s environment. Our work with Sarasota Bay dolphins has helped us better understand the normal immune system of bottlenose dolphins and establish reference intervals that can be used to assess the potential effects of man-made or natural stressors, such as the Deepwater Horizon oil spill in the northern Gulf of Mexico.
Using blood samples collected during bottlenose dolphin health assessments, our University of Connecticut lab has measured the function of different white blood cell types using functional assays. These assays include the ability of neutrophils and monocytes to engulf foreign particles approximately the size of bacteria (phagocytosis), as well as their ability to produce oxygen free radicals to kill such ingested microorganisms (respiratory burst). We also measure the ability of B and T lymphocytes to proliferate upon stimulation, which mimics the early phase of an immune response. Further, following preliminary results obtained in previous years, we validated the quantification of serum cytokines, which are small messenger molecules that direct the magnitude and direction for an appropriate immune response. The results obtained with Sarasota Bay dolphins have allowed, for the first time, the determination of confidence intervals (“normal values”) for some of those functions for which sufficient numbers of animals have been sampled. Building on past year successes, samples from May 2015 will help fill the gaps and determine reference intervals for additional immune functions. Those results in a relatively healthy population are currently used to assess the potential health effects of the recent exposure of dolphins to oil following the Deepwater Horizon spill.
This work has been supported in part by the Chicago Zoological Society, who provided logistical support and access to dolphin samples in Sarasota Bay over many years, as well as continued support from NOAA for similar analyses at different locations in the Gulf of Mexico.
This article appeared on pages 13-14 in the December 2015 issue of Nicks n Notches.