Immune regulation is effected via regulatory cells and via regulatory membrane and soluble molecules that can be potentially manipulated to prevent autoimmunity and achieve tolerance.Adaptive immune responses are based on the random generation of immunoglobulin and T cell receptors to create repertoires that cover the complete spectrum of potential foreign antigens. Because of the random nature of the immune adaptive receptors and their extensive diversity, a large fraction of the antibodies and T cell receptors that are generated every day by our B and T cells are reactive to self-components. If we add to this self-reactive capacity the notion that the immune system harbors an incredible ability to cause tissue damage and destruction, we can forever marvel how it is that most of us do not develop autoimmunity during our life. In fact, a permanent battle for balance takes place in our body to ensure that the immune system is active and effective against dangerous foreign and self (i.e., cancer-related) proteins, while it remains non reactive against us.