Brucella abortus antibody response of white Leghorn chickens selected for high and low antibody responsiveness to sheep erythrocytes.

Three experiments were conducted with lines of chickens selected for high (HA) and low (LA) antibody response to sheep erythrocytes to determine their antibody responses following primary immunization with Brucella abortus. In Experiment 1, HA chicks responded to immunization with a higher total titer than LA chicks at 7 d postimmunization. At both 5 and 7 d following immunization 2-mercaptoethanol-resistant (IgG) titers were higher in HA than LA chicks. There also was a significant sex effect at 7 d in the first experiment, with males having higher total titers than females. In the second experiment, HA chicks had higher total titers at 5 d postimmunization than LA chicks, but IgG titers were similar for both lines. Total and IgG titers of HA chicks used in Experiment 3 were significantly higher than those of LA chicks at 5 and 7 d postimmunization. Both HA and LA chicks exhibited divergent antibody responses to B. abortus although they had originally been selected for antibody responsiveness to sheep erythrocytes.