Properties and Overview of Immune Responses Flashcards
Immune System
The cells and molecules responsible for immunity
Immune Response
The collective and coordinated response of the cells/molecules of the immune system against foreign substances
First record of artificially acquired passive immunity
Chinese children, circa 15th century, inhaled powder of dry smallpox pustules
Innate immunity
Is essential for defending against microbes in the first few hours or days after infection, before adaptive immune responses have developed. Innate immunity is mediated by mechanisms that are in place even before an infection occurs (hence innate) and that facilitate rapid responses to invading microbes.
Adaptive immunity
The adaptive immune response is mediated by cells called lymphocytes and their products.
The three principal components of the innate immune system
- Physical and chemical barriers
- Phagocytic cells
- Blood proteins
Cardinal features of adaptive immune system
- Specificity and diversity
- Memory
- Self tolerance
Epitopes
Specific parts of a macromolecule that is recognized by a lymphocyte
Clonal Selection
The lymphocytes are selected by antigens when the membrane proteins present in the former recognize the antigens
Clonal Expansion
Selected lymphocytes are cloned rapidly increasing thousand of times
Diversity
The ability of the lymphocyte repertoire to recognize between 10^7 and 10^9 different epitopes
Memory
The subsequent responses to a pathogen are quicker and stronger than the first, memory cells are created after first exposure and these are more numerous and more specific to the pathogen than naive lymphocytes able to recognize the same pathogen.
Self Tolerance
The ability of the immune system to attack foreign antigens but not self antigens.
The two types of adaptive immunity
Humoral immunity and Cell-mediated immunity
Humoral Immunity
Mediate by molecules present in the body and mucosal secretions called antibodies, they are secreted by lymphocytes B. They neutralize antigens outside of cells.
