Use of an enzyme-linked immunosorbent assay to measure antibody responses in turkeys against Pasteurella multocida.

AN enzyme-linked immunosorbent assay (ELISA) and a microtiter agglutination (MA) test were used in a comparative study to measure the humoral antibody responses of turkeys receiving oral vaccination against fowl cholera. The ELISA was sensitive and measured antibody titers as high as 1:4,409, whereas the highest titers the MA test measured were 1:128. A close correlation was seen between ELISA antibody titers and protection against oral challenge with virulent Pasteurella multocida, whereas a poor correlation was seen between antibody titers measured by MA tests and protection. ELISA substrate reactions from a single serum dilution, measured with a spectrophotometer, could be converted directly from absorbance to antibody titers using a linear regression plot.