Seasonal Variation in Desert Tortoise Immune Function

Threatened Mojave desert tortoise (Gopherus agassizii) populations may be negatively impacted by upper respiratory tract disease. To more fully understand the general impact of diseases in wild populations, a more complete knowledge of the factors that contribute to immunocompetence in this species is necessary. We analyzed minimal seasonal fluctuations in innate immune function and white blood cell numbers in a colony of captive, healthy tortoises. Bacteriocidal assays measured the ability of constitutive natural antibodies and complement proteins to kill a standard strain of Escherichia coli. Ratios of heterophils to lymphocytes were used to infer relative levels of chronic stress and/or activity among the four seasons. Bacteriocidal capacity was significantly suppressed during winter relative to the other three seasons, but heterophil:lymphocytes did not vary significantly among seasons. These results suggest that tortoises may be inherently immunosuppressed during winter, but elevations in stress do not contribute to this immunosuppression.

Name thesis:degree_name

Biology

Level thesis:degree_level

Honors Thesis

Grantor

University of Nevada, Reno

Year dc:date.issued

2013

Author dc:creator

• Horn, Kelly

Advisor dc:contributor.advisor

• Tracy, Richard C.

Statement dc:rights

• In Copyright(All Rights Reserved)

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/11714/515

OAI identifier oai:identifier

oai:scholarwolf.unr.edu:11714/515