How is the structure of leukocytes different from the structure of erythrocytes?

Red blood cells carry oxygen around the body and carbon dioxide back. They do not have nuclei and they cannot reproduce, while leukocytes have them and reproduce. Leukocytes are a massive class of immune cells that are very diverse, with different structures, functions, and changing life cycles. However, their main purpose is the same: they protect humans from infections and help repair damaged tissues (mainly macrophages). Of course, due to their very different purposes, red blood cells and white blood cells also have different shapes and different surface proteins and receptors.