How does your immune system recognize and destroy germs?

Your immune system uses several layers of defense to recognize and destroy pathogens. White blood cells called lymphocytes carry receptors that detect specific molecular signatures on the surface of germs, known as antigens. When a pathogen enters the body, B cells produce antibodies that bind to these antigens, marking the invader for destruction. T cells either directly kill infected cells or coordinate the broader immune response. Innate immune cells like macrophages and neutrophils act as first responders, engulfing and digesting pathogens through a process called phagocytosis. After an infection is cleared, memory cells remain in the body, allowing the immune system to respond faster and more powerfully if the same pathogen appears again.