Evaluation of the cell-mediated immune response of chickens vaccinated with Newcastle disease virus as determined by the under-agarose leukocyte-migration-inhibition technique.

The under-agarose leukocyte-migration-inhibition (LMI) assay for the evaluation of cell-mediated immunity (CMI) was developed for use in chickens. A significant CMI response was demonstrated in chickens vaccinated with Newcastle disease vaccine by using this assay. Results also indicated that the under-agarose LMI test was a reproducible and relatively easy assay to perform. Serologic antibody titers were determined to study the correlation between hemagglutination-inhibition (HI) titers and LMI levels using the HI microassay. The presence of the CMI response always correlated to the presence of the serologic immune response and vice versa. However, the quantitative level of the CMI response did not always correspond to the quantitative level of the serologic immune response. Going by results of this study, we were unable to predict humoral antibody level on the basis of a CMI response and vice versa.