The Immune Response

The Immune Response

• The immune system is designed to recognize and combat foreign invaders, distinguishing them from the body's own cells (self vs nonself)
• Each cell carries specific molecular markers that label it as "self", which determine what makes us unique and distinguishes one person from another
• Any substance or physical structure that can be recognized by the immune system is called an antigen
• Major classes of antigens include proteins, carbohydrates, lipids, and nucleic acids
• Antigens can trigger an immune response, and complex antigens can stimulate full immune activity

Autoimmunity and Immune Balance

• If the immune system loses its ability to distinguish self from nonself, it can launch an aggressive response against the body's own tissues, leading to autoimmune disease
• The immune system maintains a balance of responsiveness, as too little response is ineffective, and too aggressive a response can lead to destruction of bystander tissues
• Regulation of immune function and overall immuno-homeostasis is under the control of multiple factors, including genetic components and environmental cues

Cluster of Differentiation (CD)

• CD refers to proteins found on the surface of cells, each with a unique number for identification
• CD molecules can be specific for one cell or cell lineage, or not
• CD designation is used to characterize cell phenotypes and has identified over 400 individual and unique markers
• CD-specific diagnostic agents are useful for determining protein functions and identifying their distribution in different cell populations

Innate and Adaptive Immunity

• Innate immunity provides the first line of defense against infectious diseases, consisting of physical barriers and biochemical factors
• Innate immune mechanisms exist from birth and include anatomic, physiologic, phagocytic, and inflammatory components
• Adaptive immunity is triggered by the innate immune response and involves a more focused set of reactive molecules and cellular components to combat specific organisms
• Both innate and adaptive components must function in concert to combat and control disease successfully

Learn about the immune system's recognition and combat of foreign invaders, and how it distinguishes between self and non-self cells. Explore what makes us unique and the different classes of antigens.