overview of immunology Flashcards
Describe the role of immune system in host defense
defense against foreign antigens: Innate immunity, Adaptive immunity
Explain tolerance and consequences of loss of tolerance
Tolerance: recognize self from nonself.
Loss of tolerance: autoimmunity. Self is attacked
Describe properties of antigens and which types of molecules are most immunogenic
- Foreign
- Chemically complex
- MW >6kD
Immunogenicity: Proteins, polysaccharides, nucleic acids, lipids (highest to lowest)
3 terms that are used to refer to the component of the antigen with which receptors on immune cells interact
- Epitope
- Antigenic Determinant
- Determinant
3 chemical barriers
- Lysozyme: present in secretions (tears, sweat, saliva) splits the cell wall of bacteria
- Spermine: in semen to destroy bacteria to protect sperm
- Acid pH in the stomach: destroy bacteria
2 physical barriers
Skin and mucosal linings
Name the four defining characteristics of innate and adaptive immune system
Adaptive: Exquisite Specificity
Lag time for first exposure
Memory
Adaptivity
Innate has none of these thingsList cells of Innate and Adaptive immunity
Innate cells: Macrophages, Neutrophils, NK cells, dendritic cells. Mast cells, basophils, eosinophils (cytokines, chemokines)
Adaptive cells: T cells and B cells
explain the role of each primary lymphoid tissues
Bone Marrow: makes B cells, eosinophils, basophils, monocytes, granulocytes, dendritic cells, mast cells.
Thymus: makes T cells.
These have central tolerance induction: if B/T cells have antigen receptors for self are destroyed on the spot. they never leave.
Peripheral tolerance: cells that escape and have these self antigen receptors need to be deleted.
Explain the role of secondary lymphoid tissues
Lymph nodes, tonsils/adenoids, Spleen, MALT: sites of action against antigens (adaptive response)
Lymph Nodes
primary follicles-B cells mature resting
secondary follicles- have germinal centers, active B cells.
- there are also macrophages, dendritic cells, follicular dendritic cells in the cortex.
Paracortex: mostly T cells with some dendritic cells
Medulla: macrophages, dendritic cells, and Plasma cells
Spleen
encapsulated, red pulp, white pulp.
White pulp=functions as the secondarylymph tissue.
PALS (periarterial lymphatic sheath surrounds central arteries/arterioles is rich in T cells. 1* and 2* follicles are outgrowths from PALS and are rich in B cells. Marginal zone contains dendritic and macrophages.
MALT (mucosa), GALT (Gut), BALT (Bronchus)
these regions have gaps that allows microbes to penetrate lining. They enter via M cells to enter Lamina Propria. LP is the site of follicles, phagocytic cells, dendritic cells, lymphocytes.
Follicle associated epithelium: has M cells (no goblet cells)
M cells have few lysosomes indicating that ther are not phagocytic cells. They have lots of vescicles so they are for transport.
3 examples of sites of entry
Peyers Patches is the GALT
Lymph Nodes in Lymph
Spleen for Blood
Cytokines/chemokines
small peptides secreted mainly by activated leukocytes. different cytokines can produce same response (functional redundancy)(pleitropic)
chemokines: cause leukocytes accumulation,
* Chemokines are chemoattractants but not all chemoattractants are chemokines.
Compliment
term for a family of proteins that facilitate elimination of microorganism. Most of the proteins are made in the liver and circulate as dormant enzymes serving as substrates for other complement proteins that have themselves been activated.
