The body’s defense system against disease-causing pathogens. Immunity is a complex process that involves lines of defense against most microbes and highly specialized responses to particular offenders. Immunity is divided into two broad categories: innate immunity and acquired/active immunity.
Innate Immunity
Your innate immune system is inherited and active as soon as you’re born. It includes physical barriers (such as the skin and mucous membranes that line the respiratory, gastrointestinal, and genitourinary tracts) and specialized cells that quickly attack pathogens that enter the body. When this system recognizes a pathogen, it releases chemicals to kill or capture the invader.
It also signals other immune cells to come to the rescue. These include NK cells, B cells, macrophages, dendritic cells, and natural killer cells. In addition, the complement system, which consists of proteins that directly kill pathogens or facilitate phagocyte uptake by opsonization, is another component of the innate response.
Acquired/Active Immunity
Over time, the innate and adaptive immune systems build “memory” about specific invaders, which allows the system to respond faster and more effectively when those same pathogens return. Vaccines support this form of immunity by training the immune system’s cells to recognize and destroy invading germs.
Maintaining a healthy diet, getting enough sleep, and receiving all recommended vaccines are important for supporting immune function. Deficiencies in certain nutrients can also weaken the immune system. These include antioxidants, vitamins C and E, folic acid, zinc, copper, and iron. If you have questions about immune function, please talk to your doctor.