In Boyne's The Boy in the Striped Pajamas, how is Bruno used as a symbol of innocence that contrasts with his reality?

Bruno's parents shield the nine-year-old boy from the reality of what their move from Berlin to Auschwitz means, implying that they understand, at least on some level, their complicity with evil--and want to protect their child from it. They simply will not answer his questions, except in generalities. So he has no context for understanding what is happening all around him, even when he moves next to the barbed wire concentration camp fence. Ignorance helps keep him innocent.
Bruno symbolizes how innocence can be manufactured by keeping people in the dark about what is happening in plain sight. His innocence also symbolizes the way context colors our perceptions: he comes from a very comfortable background. His Berlin home was large and his family had servants. He had never been hungry or forced to dress in rags or face death. Therefore, he has no experiential basis for understanding the plight of those behind the fence. His innocence also exposes the cruelly arbitrary nature of who suffers and who prospers in this world: his lack of ability to understand arises from the inherent irrationality of the system in which he lives. His ability to accept people as who they are, rather than to label, abuse, and kill them on the basis of a "racial" category, contrasts sharply with his culture.

Throughout the novel, Bruno maintains his childhood innocence despite the horrific environment around him. Bruno refers to the Auschwitz concentration camp as "Out-With" and does not understand that his father is in charge of the systematic annihilation of Jews. Bruno's naive perspective symbolically represents how innocence can withstand unimaginable horrors. Despite being a German boy, Bruno views Jewish servants and prisoners as equals without prejudice. He does not understand why Shmuel is forced to live on the other side of the fence and is unaware that his parents' relationship is suffering. One of the most significant moments throughout the novel is when Bruno and Shmuel search for Shmuel's father in the concentration camp. Bruno and Shmuel are forced to march with other prisoners as they are led to the gas chambers. Once they are inside the chamber, Bruno holds Shmuel's hand and says that he is his best friend. Despite Bruno's physical death, his innocence remains unharmed, and he is pure throughout the entire journey. Bruno's innocence symbolically represents how friendship, love, and purity can endure the most inhumane environments and experiences.