Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Biology and Microbiology

First Advisor

N. H. Granholm


The agouti locus, located on chromosome 2 of the house mouse (mus musclus), functions in the complex regulation of pigment synthesis. The complexity of its regulatory role is revealed through the aberrations that become manifest when a mutation, specifically the lethal yellow (AY) mutation, occurs at the agouti locus. The lethal yellow mutation is associated with an alteration in pigment synthesis, onset of obesity at approximately 120 days, and an increased susceptibility to cancer. Based on the putative relationship between cancer and immunity, this mutation may be correlated with altered immune mechanisms. This correlation was investigated by comparing a delayed-type hypersensitivity (DTH) response to dinitrofluorobenzene (DNFB), in vivo hormonal immunity to sheep red blood cell (SRBC), and in vitro lymphocyte reactivity of C57BL/6J Ay/a mice with congeneic a/a controls. Responses were compared between 42-day-old and 120-day-old mice to determine the correlation, if any, between altered immunity and age-onset obesity. Data indicate that the AY mutation is directly liked to a suppressed DIH response and, to some extent, a decreased reactivity to mitogen-induced lymphocyte proliferation. Obesity appears to play a role in the alteration in humoral immunity as demonstrated by an enhanced anti-SRBC IgM response and suppressed antibody-fanning cell (AFC) response to SRBC. Finally, serum from obese yellow (AY/a) mice was markedly suppressive in in vitro lymphocyte proliferation assays.

Library of Congress Subject Headings

Mice as laboratory animals

Mice -- Immunology

Immunocompetent cells




Number of Pages



South Dakota State University