Which type of blood cell is primarily involved in the immune response?

Leukocytes, or white blood cells, play a crucial role in the immune response. These cells are responsible for identifying and attacking pathogens such as bacteria, viruses, and other foreign substances that invade the body. There are different types of leukocytes, including lymphocytes (such as T cells and B cells) and phagocytes (such as neutrophils and macrophages), each with specific functions in protecting the body. For instance, lymphocytes recognize specific antigens and can either attack the pathogen directly or produce antibodies to neutralize it. This multifaceted approach makes leukocytes essential for maintaining the body's defense against infections and diseases.

In contrast, erythrocytes (red blood cells) are primarily responsible for transporting oxygen and carbon dioxide in the bloodstream, platelets are involved in blood clotting and wound healing, and antibodies are proteins produced by B cells that neutralize pathogens but are not cells themselves. Therefore, while each option plays a role in the body's function, leukocytes are specifically key players in the immune response.