The University of Georgia College of Veterinary Medicine

Georgia Veterinary Scholars Program

GVSP Summer 2011 Scholars

Georgia Veterinary Scholar	Faculty Mentor

Zachary Chillag UGA College of Veterinary Medicine Class of 2013	Dr. Vanessa Ezenwa Department of Ecology UGA Odum School of Ecology

Nitric Oxide as an Index of Innate Immunity in Grant's Gazelle

Zach Chillag, J. Ewoi, A. Hines, A. Mwachanje, M. Rajeev, M. Snider, V.O. Ezenwa

Measures of immune function in free-living wild mammals are difficult to obtain, however, there is an increasing need to assess how immunity varies in the wild and to determine the causes and consequences of this variation. Innate, cell mediated, and humoral components of immunity play distinct roles in surveillance, pathogen mitigation, and wound healing, however they are heavily dependent on one another to induce the highly organized signaling cascades that facilitate the immune response. The innate component of the immune system is the first line of defense against pathogens, initiating these cascades by releasing cytokines, chemokines, and other mediators that affect the other two components. In particular, granulocytic leukocytes release nitric oxide in response to injury or pathogens, signaling other immune processes and creating reactive nitrogen species that aid in pathogen destruction. Assays of nitric oxide are commonly used to measure the immune response to toxins, and have recently been used as a measure of the innate immune response in wild birds. In this study, we apply this technique to a wild mammal, Grant's gazelle (Nanger granti), to test its efficacy as an index of the innate immune response in this species. We will examine variation in nitric oxide levels across individuals as it relates to sex, reproductive status, condition and in vitro challenge with lipopolysaccharide (LPS). We expect that ecological and life-history traits (e.g. reproduction, condition) that alter immune investment will influence baseline nitric oxide levels and responses to LPS challenge. To date, all study animals have been captured and sampled, in vitro LPS challenges have been completed, and nitric oxide assays have been performed. Analysis of assay data is ongoing.