Meeting Abstract

P2.30  Wednesday, Jan. 5  Comparative wild rodent immunology: How does life history relate to immunity? HANSELMANN, Rhea*; JOLLES, Anna; Oregon State University; Oregon State University hanselmr@onid.orst.edu

Rodents belong to the most abundant and diverse order of mammals and are important in the spread of many infectious diseases. Reservoir competence, the ability of a susceptible host to acquire, viably harbor, and transmit an infectious organism, varies greatly among rodent species. However, the immunological basis for these differences remains unclear. For certain diseases (e.g. Lyme disease), reservoir competence is high in abundant, smaller species with “fast-paced” life histories. Here, we investigate the relationship between the varying life history patterns of wild rodents and their immune strategies. By applying immunological assays targeting innate vs. adaptive as well as constitutive vs. induced immunity to a range of wild rodent species, we examine the hypothesis that “fast-paced” species invest more in “cheap”, non-specific immune defenses, whereas “slower-paced” animals are more likely to evolve more “expensive”, specific immune strategies. More than 200 individuals comprising ten species were sampled in four geographic areas of Oregon. We used total and differential leukocyte counts to assess constitutive innate and adaptive immunity. Induced innate immunity was measured using a whole blood bactericidal assay against E.coli. To quantify induced adaptive immunity we are developing a lymphocyte proliferation assay and an in vivo assay measuring local tissue swelling in response to mitogen stimulation. Elucidating the relationship between life history and immune strategies employed by different rodent species may allow us to predict a species’ potential for reservoir competence. Considering continual habitat degradation and loss of species diversity, this knowledge will aid in making predictions regarding the possible consequences of ecosystem alterations on disease prevalence.