Immunology 1: cells of the immune system (humoral & cellular immunity) Flashcards
cells, tissues, and molecules that mediate resistance to infections.
Immune system
Study of structure and function of the immune system
Immunology
Study of out protection from foreign macromolecule or invading organisms and our response to them
Immunology
Foreign macromolecule (virus protein, worms, parasite) (everything that should not be in the body)
Antigen
Resistance of a host (human) to pathogens and their toxic effects
Immunity.
Collective and coordinated response to the introduction of foreign substances in an individual mediated by the cells and molecules of the immune system.
Immune response.
The immune system is a collection of what?
1- organs.
2- cells.
3- molecules (soluble factors).
Where do leukocytes develop?
Primary (central) lymphoid organs.
List primary (central) lymphoid organs?
1- bone marrow.
2- thymus.
Where does the immune response occur?
Secondary (peripheral) lymphoid organs.
List secondary (peripheral) lymphoid organs?
1- lymph nodes.
2- spleen.
Where is the bone marrow located?
Middle of bones (vertebrae, pelvic, and leg bones).
What does bone marrow generate?
T cells, B cells, and macrophages.
Where is the thymus located?
In the front of the upper chest.
What is the thymus function?
Acts like a nursery for the development of T cells.
Where are lymph nodes located?
Throughout the body.
What is the lymph nodes function?
Filters lymph fluid, removing antigens that get trapped in their web like structure where macrophages, antibodies, and T cells can destroy them.
Where is the spleen located?
In the upper left side of the abdomen.
List the 4 functions of the spleen?
1- filters out foreign organisms that infect blood.
2- removing old or damaged platelets and RBCs.
3- storing extra blood and releasing it as needed.
4- helping form some types of WBCs.
What can be done to the spleen if it’s damaged?
It can be removed but that lowers resistance to infection.
List other lymphoid organs?
1- tonsils and adenoids.
2- payer’s patches.
3- appendix.
4- lymphatic vessels.
List the 3 types of accumulation of lymphoid tissues?
1- MALT (mucosa associated lymphoid tissue).
2- GALT (gut associated lymphoid tissue).
3- BALT (bronchus associated lymphoid tissue).
How are lymphatic organs interconnected?
By the blood and lymphatic vessels through which lymphocytes circulate.
All immune cells arise from which stem cell?
Hematopoietic stem cell.
List the 3 types of bone marrow progenitor?
1- common lymphoid progenitor.
2- myeloid progenitor.
3- erythroid progenitor.
Common lymphoid progenitor is precursor of which immune cells?
B cells, T cells and NK cells.
B cells are precursors of which cells?
Plasma cell.
T cells are a precursor of which cells?
Effector T cells.
Myeloid progenitor is a precursor of which immune cells?
Polymorphonuclear leukocytes (neutrophils, eosinophil, basophil).
Which immune cells come from an unknown precursor?
1- mast cells.
2- dendritic cells.
Monocytes are a precursor of which immune cells?
Macrophages.
List WBCs?
1- dendritic cells.
2- monocytes (macrophages).
3- eosinophil.
4- lymphocytes (B lymphocytes, T lymphocytes, NK cells).
5- neutrophils.
6- basophils.
What is the percentage of monocytes and macrophages in blood?
5-8%
_________ circulate in the blood, ________ in the tissues.
Monocytes, macrophages.
Monocytes and macrophages are an important link between what?
Innate and acquired immune responses.
Which changes occur during the change of monocytes to macrophages?
1- cell enlarge (5-10x).
2- intracellular organells increase in size and complexity.
3- cells acquire increased phagocytic ability.
4- increased secretion of many soluble factors.
Macrophages are dispersed throughout the body some becoming ________ macrophages, whereas others remain _______ and are called _____ or __________ macrophages.
Fixed,
Motile,
Free,
Wandering.
Macrophages play which important roles?
1- phagocytosis.
2- opsonization.
3- ADCC (Antibody-dependent cellular cytotoxicity).
4- APCs (Antigen presenting cells).
5- secretion of cytokines (called monokines).
6- synthesis of complement components.
List monokines that get secreted by macrophages?
1- IL-1.
2- IL-6.
3- IL-8.
4- IL-12.
5- IL-15.
6- IFN.
7- TNF.
8- prostaglandins.
Macrophages are activated by a variety of stimuli, list the?
1- activating comes from chemokines.
2- phagocytosis itself is an important activating stimulus.
3- cytokines secreted by T helper cells (IFN - gamma).
4- mediators of the inflammatory response.
5- microbial products (such as LPS).
Where do dendritic cells originate from?
The bone marrow.
What makes dendritic cells very efficient at contact with foreign material?
They have dendriform (star shaped).
What do dendritic cells function as?
APC (capture antigen or bring it to the lymphoid organs where an immune response is initiated).
What do dendritic cells express?
Class I and II MHC (major histocompatibility complex) molecules.
Where are dendritic cells present?
Blood, LNs and epithelial cells.
Give an example of dendritic cells?
Langerhan cells (skin).
List types of tissue macrophages and where are they?
1- alveolar macrophage (lung).
2- osteoclast (bone).
3- histiocyte (CT).
4- kupffer cell (liver).
5- microglia (brain).
6- intestinal macrophage (intestine).
Where are mast cells released from?
Bone marrow as undifferentiated and differentiate in the tissues (skin, CT, mucosal epithelium, etc).
Mast cell’s morphology and function similar to ________
Basophils.
Which receptors do mast cells have?
Have Fc receptors for IgE (FceRs).
Mast cells play a very important role in what response?
Allergic response.
What do mast cells produce?
A variety of cytokines.
What are polymorphonuclear leukocytes (PMNs)?
Granulocytes.
List the 3 types of granulocytes?
1- neutrophils.
2- eosinophils.
3- basophils.
What are PMNs important for?
Removal of bacteria and parasites from the body, they engulf these foreign bodies and degrade them using their powerful enzymes.
What is the percentage of neutrophils in the blood?
50-70% of circulating WBC.
A higher number of neutrophils are suggestive of what?
Bacterial infection.
Which WBC have multi-lobed nucleus with poorly stained fine granules?
Neutrophils.
What enzymes do neutrophils contain?
Bactericidal enzymes.
List the bactericidal enzymes found in neutrophils?
Lysozome, NADPH oxidase, lactoferrin and B-12 binding protein, defensins, elastase and myeloperoxidase.
Which WBCs are efficient phagocytes?
Neutrophils.
Neutrophils don’t function as what?
APCs.
Which type of receptors do neutrophils have?
Receptor for Fc region of IgG and C3b.
Which WBC are the first to arrive?
Neutrophils.
Which WBCs are the most important cells of the innate immune system?
Neutrophils.
Which is the percentage of eosinophils in the blood?
1-3% of circulating WBCs.
Which WBCs are bi-lobes nucleus and a heavily granulated cytoplasm?
Eosinophils.
Eosinophils don’t act as what?
APCs.
Which type of receptors do eosinophils have?
Receptors for complement.
What is the major role of the eosinophil?
Is believed to be against parasite.
How are eosinophils effective against parasites?
Bind to IgE on surface of a worm, the contents of the granules (hydrolytic enzymes) cause damage to the worm’s tegument.
What eosinophil protein is highly toxic to worms?
Major basic protein (MBP).
Eosinophils are classically seen with which conditions?
1- atopic allergies.
2- worm infections.
3- collagen vascular diseases.
4- neoplastic disorders.
5- skin rash.
What is the percentage of circulating basophils?
<1% of circulating WBC.
Basophils are only present where?
Bloodstream
Which WBC is a lobed nucleus- more variable, large coarse granules?
Basophils.
Basophils play a major role in what? And how?
Allergic response, they release histamine, serotonin, heparin, prostaglandin….. etc into the bloodstream.
Which receptors do basophils have?
Fc receptors for IgE (FceRs).
How do basophils act when an individual is exposed to an allergen? What happens upon re-exposure?
When an individual is exposed to an allergen, allergen specific IgE is produced, this IgE binds to the surface of basophils.
Upon re-exposure to the allergen, the allergen binds to IgE on the surface of basophils resulting in degranulation [effector phase].
Which WBCs are agranulocytes?
Lymphocytes.
Lymphocytes are responsible for what?
Specific immune response.
What is the percentage of circulating lymphocytes?
20-40%
Which lymphocytes return 99% of cells in lymph by extravasating and entering the tissues?
Lymphocytes
T and B lymphocytes are _____, ______, ___________ cells which ________ be distinguished from each other morphologically.
Small, motile, non-phagocytic cells which cannot be distinguished.