Meeting Abstract
P3.30 Saturday, Jan. 5 Rabies neutralizing antibody production, relative immune function and life-history traits in the big brown bat, Eptesicus fuscus MOORE, M/S*; JACKSON, F/R; MENDON�A, M/T; MCCRACKEN, G/F; KUNZ, T/H; Boston University; Centers for Disease Control and Prevention in Atlanta; Auburn University; University if Tennessee; Boston University mmoore@bu.edu
Innate and adaptive immune functions provide vertebrates mechanisms used against invading pathogens, and the relative strength of these responses affect how animals respond physiologically to exposure and infection. This study characterized immune responses in the big brown bat, Eptesicus fuscus, and how immune function variation may relate to population differences, life-history traits and pathogen exposure. To measure the innate immune response, blood was used in a bactericidal assay and was diluted, mixed and incubated with a standard concentration of Escherichia coli. To assess the cell-mediated adaptive response, bats were injected with phytohemagglutinin (PHA), a known T-cell mitogen. Assessment of pathogen exposure was conducted using the rapid fluorescent focus inhibition test to measure virus-neutralizing antibodies (VNA) induced by rabies antigens. Significant relationships were observed between production of VNA and reproductive stage. Pregnant and lactating individuals were more likely to exhibit active production of VNA compared to postlactating individuals. Bactericidal ability of blood was significantly related to colony, age and reproductive stage. Subadult bats showed greater bacterial killing compared to adults and postlactating bats showed greater bacterial killing compared to lactating bats. Regression analysis did not significantly explain variation in PHA index. Results suggest that reproductive status, age and colony site may influence the ability of bats to respond immunologically, particularly through the innate immune response. Additionally, pregnant and lactating individuals, which exhibit increased gregarious behavior compared to bats in other reproductive stages, appear to be more susceptible to pathogen exposure.
