Explain in layman's terms the role of passenger dendritic cells in organ rejection

What will be an ideal response?

Passenger cells are those white cells that are located within the donor organ at the time the organ is transplanted. They are carried within the donated organ and are transplanted into the recipient. These cells are capable of identifying the recipient's tissues as "foreign" and instigating an immune reaction. Once an immune reaction is started, the recipient's immune system attacks the donated organ, potentially leading to partial or complete rejection (destruction) of the organ.