Immunology is the branch of science that studies the immune system, which is our body's defense mechanism against infections and diseases. It helps us understand how our body recognizes harmful invaders like bacteria, viruses, and fungi, and how it responds to protect us. By learning about the immune system, scientists can develop vaccines and treatments to improve our health. The immune system consists of various cells, tissues, and organs, including white blood cells, lymph nodes, and the spleen. These components work together to identify and eliminate threats. Immunology also explores how the immune system can sometimes malfunction, leading to conditions like allergies or autoimmune diseases, where the body mistakenly attacks itself.