The immune system is designed to identify and destroy pathogens by recognizing self from non-self. The immune system has multiple subdivisions that are capable of handling a wide array of threats, from foreign invaders to malignant growths. Two general categories within the immune system include the innate and adaptive immune systems.
- The innate component is non-specific and is the first line of defense involving, among other components:
- Pathogen Associated Molecular Proteins (PAMPs) - present on microbes
- Pathogen Recognition Receptors (PRRs) and Toll-like Receptors - present on leukocytes
- Phagocytosis and complement to remove non-specific foreign substances
- The adaptive component is specific and requires a series of activation steps to make a robust, "personalized" immune response against the insulting antigen and can be:
- Cell-mediated - which does not include antibody production but involves apoptosis and the activation of phagocytes, some cytotoxic T-cells, and cytokines in response to antigenic stimulation
- Humoral - which involves the production of antibodies
- Includes memory cell formation
