CD8A and Menkes disease: Vaccination of chickens against MDV may induce cytotoxic T cell response to lytic antigen pp38  (37), however, the role of vaccine-induced pp38-specific cytotoxic T cell response in the control of MD is currently unknown. It has been suggested that memory, but not effector, CD8 T cells can provide protection against infectious bronchitis virus (IBV) infection in the IBV-susceptible B19 haplotype chicken line (38).