SUMMARY An enzyme-linked immunosorbent assay (ELISA) was developed to detect the humoral antibody response in chickens receiving subcutaneous injections of the CU vaccine strain of Pasteurella multocida. Serum samples were collected twice weekly for 3 weeks, and chicken antibody responses were monitored using ELISA. The positive/negative ratio method of analysis was used to determine the antibody titer of vaccinated chickens. After a loge transformation of the ELISA titer, a linear relationship was confirmed between ELISA titer and positive/negative ratio. Regression analysis was used to construct a standard curve and derive an equation from this relationship. Using this equation, only one dilution was needed to determine the antibody titer of any unknown serum sample. The ELISA technique was used to monitor the mean antibody titer of vaccinated chickens over the 3-week period. A classic primary response curve occurred when titer was plotted against time. RESUMEN

https://www.jstor.org/stable/info/1590143

An enzyme-linked immunosorbent assay for detecting antibodies to Pasteurella multocida in chickens.

Development of immunization trials 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.

Use of an Enzyme-Linked Immunosorbent Assay to Measure Antibody Responses in Turkeys Against Pasteurella multocida^

The nature of the systemic immunity induced by various vaccines against fowl cholera disease in turkeys was investigated. Used as vaccines were three avirulent strains (CU, M2283, and P1580) of Pasteurella multocida administered in the drinking water and a bacterin administered parenterally. A passive hemagglutination test was developed to measure levels of systemic humoral immunity. Systemic cell-mediated immune response was assayed by an in vitro immunostimulation microculture system utilizing peripheral blood lymphocytes. The bacterin induced high levels of systemic humoral and cell-mediated immune responses which respectively persisted for 8 and 6 weeks. The CU strain of live vaccine induced average levels of systemic immunity (humoral and cell-mediated) which respectively persisted for 4 and 6 weeks. The M2283 strain of live vaccine also induced average levels of systemic immunity (less than induced by the CU strain) which respectively persisted for 4 and 6 weeks. The P1580 strain of live vaccine induced low levels of systemic immunity which persisted for only 2 weeks. Results from data generated from an analysis of correlation between levels of immunity and protection indicate that systemic immunity (humoral and cell-mediated) played a significant role.

Studies on Pasteurella multocida. VI. Nature of systemic immunity and analysis of the correlation between levels of immunity induced by various fowl cholera vaccines and protection against challenge.

An indirect enzyme-linked immunosorbent assay (ELISA) was developed to measure humoral antibody responses of chickens against Pasteurella multocida. A standard indirect hemagglutination (IHA) test was used to compare serologic results with those of ELISA. The ELISA was also used following challenge with P. multocida to compare the efficacy of three commercial fowl cholera vaccination regimens. Although antibody titers measured by ELISA and IHA were highly correlated, ELISA was at least twice as sensitive as IHA. Antibody measured by ELISA and IHA also correlated significantly with protection against P. multocida challenge. No mortality occurred in any of the three vaccinated challenged groups. However, control unvaccinated chickens experimentally infected with P. multocida developed signs of acute pasteurellosis and died by the 10th day post-challenge. Impression smears made of hepatic tissue from all chickens were stained (Wright's stain), and typical bipolar rods characteristic of Pasteurella were identified in smears from unvaccinated challenged controls only.

Comparison of Enzyme-Linked Immunosorbent Assay and Indirect Hemagglutination Test for Quantitating Antibody Responses in Chickens against Pasteurella multocida

Stephen R. Coates

Papers

The Response of Turkeys to Varying Doses of Live Oral Pasteurella multocida Vaccine