BSI 2 Lecture 5-7: Immunology Flashcards
What are the two principal mechanisms/systems which protect our bodies from invasion?
Phagocytosis and the production of specific antibodies and sensitized lymphocytes
What is innate immunity?
The non-specific ability, that we are born with, to phagocytize foreign organisms, particles, some cancerous cells, and exhausted/worn out cells
What is acquired or adaptive immunity?
The ability to produce antibodies and memory cells which remember the antigen so your body can mount a quicker, more effective response with subsequent exposure
What are the mediators of the innate immune response?
leukocytes
What is the most numerous leukocyte found in the body?
Neutrophil
How many white blood cells are there in one microliter of blood?
4800-11,000
How do leukocytes move around in the body?
Via the blood and lymph
What leukocytes are formed in the bone marrow?
granulocytes, monocytes, and a few lymphocytes
What leukocytes are formed in the lymphoid tissue?
lymphocytes and plasma cells
What cells seek out invading organisms by chemotaxis?
granulocytes and monocytes
How many types of white blood cells are usually found in the blood?
5 types
Are there more red blood cells or white blood cells in the body?
Red blood cells (4-6 million)
What can cause an increase in white blood cell count?
An infection or leukemia
What is the breakdown in the percentage of the 5 types of white blood cells in the body?
62% neutrophils 30% lymphocytes 5.3% monocytes 2.3% eosinophils 0.4% basophils
Name the granulocytes
1) neutrophils
2) eosinophils
3) basophils
Why are they called granulocytes?
Because they have intracellular granules that stain with certain dyes plus they have multilobed nuclei.
Which granulocytes tend to have bilobed nuclei?
Eosinophils and basophils
Which granulocyte tends to have many lobes?
Neutrophils
Granulocytes, together with ______, protect primarily by _______ via our _______ immunity.
Monocytes, phagocytosis, innate
______ and ______ act principally by the production of specific antibodies via our _______ immunity.
Lymphocytes, plasma cells, acquired/adaptive
Why are natural killer cells considered part of the innate immune response?
Because they can operate independently without Helper cell activation
Where do white blood cells originate from?
The same pluripotent hematopoietic stem cells as red blood cells
What 2 principal cell lines do white blood cells become committed to?
myelocytic and lymphocytic
What does the myoblast (myelocytic) line, in the bone marrow, produce?
granulocytes and monocytes
What does the lymphoblast (lymphocytic) line, in the lymphoid tissue, produce?
lymphocytes and plasma cells
What are the principal mechanisms of the innate immune response?
Non-specific phagocytosis and inflammation
Where are neutrophils, basophils, eosinophils, and monocytes produced?
In the bone marrow
What are the two functions of Neutrophils?
1) phagocytosis
2) release chemicals involved in inflammation
What is the function of a basophil?
To release histamine and other chemicals involved in inflammation in the blood
What are the functions of Eosinophils?
1) Kill parasites
2) Participate in hypersensitivity reactions
What are the functions of Monocytes?
They carry out functions in the blood similar to macrophages
What are the functions of Macrophages?
1) Phagocytosis
2) Extracellular killing via secretion of toxic chemicals
3) Process and present antigens to helper T cells
4) Secrete cytokines involved in inflammation, activation and differentiation of helper T cells, and systemic responses to infection
What is the function of a Mast cell?
Release histamine and other chemicals involved in inflammation
Where does interleukin 1, tumor necrosis factor, and interleukin 6 come from?
Antigen presenting cells
What does interleukin 1, tumor necrosis factor, and interleukin 6 target?
1) Helper T cells
2) certain brain cells
3) numerous systemic cells
What are the major functions of interleukin 1, tumor necrosis factor, and interleukin 6?
1) Stimulate IL-2 secretion and IL-2 receptor expression
2) Induce fever
3) Stimulate systemic responses to inflammation, infection, and injury
Where does Interleukin 2 come from?
Most immune cells
What does Interleukin 2 target?
1) Helper T cells
2) Cytotoxic T cells
3) NK cells
4) B cells
What are the major functions of Interleukin 2?
1) Stimulate proliferation
2) Promote conversion to plasma cells
Where do Interferons come from?
Most cells types
What cells do Interferons target?
Most cell types
What is the function of Interferon?
To stimulate cells to produce antiviral proteins (nonspecific response)
Where does Interferon-gamma come from?
NK cells and activated Helper T cells
What cells does Interferon-gamma target?
NK cells and macrophages
What is the function of Interferon-gamma?
Stimulate proliferation and secretion of cytotoxic compounds
Where do Chemokines come from?
Damage cells (including endothelial cells)
What cells do Chemokines target?
Neutrophils and other leukocytes
What is the function of Chemokines?
Facilitate accumulation of leukocytes at sites of injury and inflammation
What cells produce Colony-stimulating hormone?
Macrophages
What is the target of colony-stimulating hormone?
bone marrow
What is the function of colony-stimulation hormone?
To stimulate proliferation of neutrophils and monocytes
What does macrophages release in the third step of the innate response? And what does it do?
Colony-stimulation hormone; it triggers more leukocytes in response to inflammation
Where are the majority of white blood cells stored?
In the bone marrow and lymphoid tissue
What is the typical life span of a granulocyte?
4-8 hours in the blood plus 5-6 days in the tissues where needed
What is the typical life span of a monocyte?
10-20 hours in the blood before entering the tissues and turning into macrophage where is can survive for months
Where in the body is there NO chemotaxis?
The bloodstream
What is the process called when mobile cells squeeze through gaps in the capillary endothelium?
Diapedesis
What is the process called when these mobile cells follow “chemical trails” to the source?
Chemotaxis
What is released by damaged cells to start the process of chemotaxis?
Chemokines
Phagocytosis is a special form of _________?
Receptor-mediated endocytosis
What happens to the phagosome once it is internalized?
It fuses with a lysosome to digest the pathogen
Where are neutrophils usually found?
In the blood stream
Where a macrophages typically found?
In the tissue
When there is inflammation or damage, what two types of cells are attracted chemotaxis?
Neutrophils and mature monocytes
Can the complement system be activated without the involvement of antibodies?
Yes, in the innate system there is the alternate complement pathway
How does the complement pathway work in innate immunity?
Factor C3b binds to the surface of the bacteria and links it to a phagocyte to be destroyed
What is the term for the targeting of a pathogen by C3b to be destroyed by phagocytosis?
Opsonization
What else is recruited during opsonization?
Other proteins which form the membrane attack complex (MAC)
What does the membrane attack complex do?
It perforates the bacterial membrane making them leaky, which kills the bacteria
Which one is a more potent phagocyte? Neutrophils or Macrophages?
Macrophages
What is the name of the cell when the pathogen is engulfed, internalized, and is now connected to a lysosome?
Phagolysosome
What can Neutrophils and Macrophages do if a bacteria is resistant to digestion?
They can release bactericidal enzymes that can kill most bacteria
What are some of these potent bactericidal enzymes?
Reactive oxygen species: superoxide, hydrogen peroxide, and hydroxyl ions
What bactericidal chemical is formed from the reaction of H2O2 and Cl by the enzyme myeloperoxidase?
Hypochlorite (bleach)
What bacteria can resist even these strong bactericidal agents?
tuberculosis bacillus
Certain tissues have their own type of macrophages. Where are Kupffer cells located? What about Dendritic cells/histiocytes?
1) Liver
2) Skin
If an invading organism makes it through to the blood, what can remove them?
The reticular systems of the spleen and macrophages in the bone marrow
What does the release of histamine cause?
Vasodilation for increased blood flow and increased permeability of proteins out of the capillaries
What leaks out into the ECF allowing it to clot and limit the spread of any pathogens?
Clotting factors, including fibrinogen
What has to be present in order for a luekocyte’s selectin ligand to bind to selectin on the tissue and for its integrin to bind to the integrin ligand?
Chemokines
What is the process of margination?
Some of the substances released from the damaged tissue alter the smooth endothelial surface so neutrophils can attach
Which method is stronger? Margination or Selectin/integrin ligand-receptor interactions?
Selectin/integrin ligand-receptor interactions
What process happens that further enhances diapedesis?
The connections between capillaries and venules loosen allowing a 4 fold increase in the number of neutrophils released
What is the first response in innate immunity?
Macrophages that are already in the tissue
What is the secondary response in innate immunity?
Neutrophils are recruited to the site by margination
What is the tertiary response in innate immunity?
Immature monocytes enter the affected tissue and become functional macrophages
What do macrophages release to trigger more production of leukocytes?
CSF
What type of corticoid is released from the adrenal glands?
Glucocorticoids
What inhibits the immune system?
Cortisone
Are eosinophils strong at phagocytosis?
No
What is the larvacidal polypeptide called that eosinophils release to kill parasites?
Major Basic Protein
Basophils and Mast cells are very important in some kinds of _______.
Allergic responses
What is leukemia?
Cancerous mutations of WBC precursor cells which result in the uncontrolled production of WBC’s
What are the two types of leukemia?
myelogenous and lymphocytic
What happens if the type of leukemia is an acute condition?
The cells are more undifferentiated and have less function; therefore, death can result in a few months
What happens if the type of leukemia is chronic?
The cells are more differentiated and the disease may develop slowly over 10-20 years
