The immune system is a complex network that constantly works to protect the body from antigens, which have associations with pathogens, including bacteria, toxins, parasites, and viruses. The immune system offers two lines of defense: innate immunity and adaptive immunity. Innate immunity is the first line of defense and consists of physical barriers, such as the skin and mucous membranes and chemical and cellular defenses. The innate immune system is nonspecific because it reacts the same way to all foreign invaders. If the innate immune system is ineffective against a potential threat, the adaptive immune system takes over. The adaptive immune system consists of specialized blood cells and proteins that target the specific cause of infection. The adaptive immune system has a “