Development and testing of species-specific ELISA assays to measure IFN-gamma and TNF-alpha in bottlenose dolphins (Tursiops truncatus)

Authors: EBERLE, KIRSTEN - Iowa State University; VENN-WATSON, STEPHANIE - National Marine Mammal Foundation; JENSEN, ERIC - Us Navy Marine Mammal Program Biosciences Division, Space And Naval Warfare Systems Center Pacific; LABRESH, JOANNA - Kingfisher Biotech, Inc; SULLIVAN, YVONNE - Kingfisher Biotech, Inc; KAKACH, LAURA - Kingfisher Biotech, Inc; Sacco, Randy

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2017
Publication Date: 1/5/2018
Citation: Eberle, K.C., Venn-Watson, S.K., Jensen, E.D., Labresh, J., Sullivan, Y., Kakach, L., Sacco, R.E. 2018. Development and testing of species-specific ELISA assays to measure IFN-gamma and TNF-alpha in bottlenose dolphins (Tursiops truncatus). PLoS One. 13(1):e0190786. https://doi.org/10.1371/journal.pone.0190786.
DOI: https://doi.org/10.1371/journal.pone.0190786

Interpretive Summary: Studies described herein were conducted in collaboration with the US Navy Marine Mammal Program. The purpose of the present manuscript is to develop and validate the first known assays to measure specific immune system proteins in samples obtained from common bottlenose dolphins. Samples collected from four common bottlenose dolphins included serum and culture media from blood cells cultured in the presence of known immune system stimulants. Data produced from these assays is presented. These assays will be of benefit to researchers and veterinarians monitoring bottlenose dolphin health to complement currently available diagnostic tests.

Technical Abstract: Monitoring the immune status of cetaceans is important for a variety of health conditions. Assays to quantify cytokines, especially pro-inflammatory cytokines, could be employed, in addition to currently available diagnostic assays, to screen for alterations in the health status of an animal. Though a number of immunological assays are readily available for humans and mice, specific assays for many veterinary species, including cetaceans such as bottlenose dolphins (Tursiops truncatus), are more limited. Herein, we describe the development of IFN-gamma (IFN-') and TNF-alpha (TNF-a) enzyme-linked immunosorbent assays (ELISAs) specific to bottlenose dolphins. Utilizing these assays, we monitored the immune status of bottlenose dolphins from a managed population over a period of eleven months. The ELISA assays developed for bottlenose dolphins were used to measure IFN-' and TNF-a in serum or in culture supernatants from peripheral blood mononuclear cells (PBMCs) stimulated with varying concentrations of mitogens concanavalin A (ConA) or phytohemagglutinin (PHA). Induction of TNF-a in PBMC cultures was consistently highest with 1 µg/mL ConA, while 1 µg/mL PHA induced the highest secretion of IFN-'. Serum levels of TNF-a and IFN-' remained relatively constant for each animal over the time period examined. CBC and plasma chemistry variables measured concurrently in the bottlenose dolphins were then examined as independent predictors of cytokine levels. We found these clinical variables were more likely to predict linear changes in serum IFN-' and TNF-a levels compared to concentrations of these cytokines in mitogen-stimulated PBMC culture supernatants. Cytokine assays developed will be of substantial benefit in monitoring bottlenose dolphin health as an adjunct to currently available diagnostic tests.