The immune system consists of factors that provide innate and acquired immunity, and has evolved to become more specific, complex, efficient, and regulated. One of the principal functions of the human immune system is to defend against infecting and other foreign agents by distinguishing self from non-self (foreign antigens) and to marshal other protective responses from leukocytes. The immune system, if dysregulated, can react to self antigens to cause autoimmune diseases or fail to defend against infections.
Copyright © 1996, The University of Texas Medical Branch at Galveston.