Coupled longitudinal monitoring of the humoral and cellular immune response in blood was restricted to the homologous protection setting, starting at 13 dpv with five vaccine recipients (from group I), five birds admin-istered only adjuvant (group IV) and five non-vaccinated birds (group VI). At subsequent time points (20 dpv: prior to challenge, and 3, 5, 7, 14 dpc), serum for anti-body investigation was collected from all the birds. Blood for investigation of cellular immunity was collected at the same time points in the homologous protection set-ting (groups I, II, IV, VI), keeping the sampled individuals consistent throughout the experiment (n = 5/group and all the remaining birds for the final measurement).