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what are the two lines of defense vs. pathogens?
- 1) non-Specific defense ( Guard against any pathogen)
- 2) Specific defense ( A response against a very specific target)
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What is specific defence and what cell is it carried out by?
- * Mount a response against a very specific target
- *Carried out by Lymphocytes that recognize a specific invader
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7 non-specific defense mechanisms
- 1) Species resistance
- 2)Mechanical Barriers
- 3)Chemical barriers
- 4)Fever
- 5)Natural Killer Lymphocytes
- 6)Inflammation
- 7)Phagocytosis
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What is a virus?
A very small piece of a DNA or an RNA never both
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Chemical barrier:
Interferons (4)
- *Hormone like pedtides that serve as anti-viral substances
- *Produce by virus or infected cell
- *Interfere with viral transcription
- *may induce nearby cells to produce anti-viral enzymes
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During a fever what happens to iron levels in the blood?
Goes down
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2 Fuctions of NK cells (lymphocytes)
- *responsible for recognizing and destroying abnormal cells
- *Defend the body by releasing PERFORINS (little holes) which destroys effected cell
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6 Major inflammatory response
- 1)Blood vessels dialate
- 2)Increase capillary permeability
- 3)Increase white blood cells
- 4)Increase in body fluids and fibrin
- 5)Fibroblast (scar tissue)
- 6)Pagocytosis and cell replacement
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What are the 2 most active phagocytes during phagocytosis, the size of the particle they consume, and how do they leave the blood stream ?
- 1)Neutrophils (small particles)
- 2)Monocytes (large particles)
-Leave blood stream via diapedesis
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during phagocytosis monocytes become what?
Macrophages- some fixed some free
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What are the 3 mononuclear phagocytic system?
- 1)Monocytes
- 2)Macrophages
- 3)neutrophils
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What is immunity ?
The response by the body against specific, recognized foreighn antigens. Self vs non-self. The resistance to specific pathogens.
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What is another name for an antigen?
Agglutinogens
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What is an antigen?
The body inventory of "self proteins" capable of elicting an immune response.
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What is a Hapten?
A small molecule that combines with and antigen and becomes antigenic.
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What is an Antigenic?
Capable of starting an immune response.
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During fetal development red marrow releases what percent of T-lymphocytes into circulation?
70-80%
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Where do B-cells mature?
Bone Marrow
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What is the precursor of a t-cell?
Thymocytes
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What % of B-Cells are circulating lymphatic organs?
20-30%
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What is an antigen presenting cell?
A macrophage that has ate the bacterium and it shows on the macrophages surface.
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What stimulates the B-cells to divide and make copies of themselves?
Helper T-Cells
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What do B-cells divide themselves into ?
Plasma cells and memory cells
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What is Cytokines and what cell is it released by?
released by activated t-cells to enhance cellular response to antigens.
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What is proliferate?
increase , multiply, go forward
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what are the 4 types of cytokines?
- colony stimulating factors
- interferons
- interleukins
- tumor necrosis factor
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what is a colony stimulating factor?
A type of cytokine that stimulates bone marrow to produce lymphocytes.
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Cytokine Specific immunity
What do interferons do? (3)
- Block viral replication
- stimulate macrophages to engulf viruses
- stimulate B cells to produce antibodies
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What are interleukins and what do they do?
They are a type of cytokine, in specific defenses , that control lymphocyte differentiation and growth
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How do t-cells attack foreighn antigen bearing cells?
By direct cell to cell contact, providing cell mediated immunity.
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How is a t-cell activated?
They must first come in contact with a macrophage displaying the same antigen, if the antigen fits the right helper t-cell , then it becomes activated.
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What are the three major types of t-cells
- Helper t-cells
- memory t-cells
- cytotoxic t-cell
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What stimulates the B-cells?
Cytokines
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memory t-cell
has a no-delay response to any future exposure to the same antigen.
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what are Cytotoxic cells and what type of cell is it?
specialized T-cells thatcontinually monitor the bodys cells, and gets rid of virus and tumor infected cells by realeasing perforin.
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What are the functions of b-cells?
B-cells attack pathogens by differentiating into plasma cells that secrete antibodies, small number of these will become memory cells.
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Antibody mediated immunity
- Antigens are destroyed through body fluids.
- *cytokines dont go through air they go through fluids.
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what group do antibodies belong to ?
immunoglobulins
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How is a b-cell activated?
When an activated helper t-cell encounters a b-cell (which has already encountered an antigen) The helper T cell releases cytokines. This may activate the b-cell to divide and make copies.
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what are plasma cells?
Specialized b-cells that produce and secrete a produce antibodies.
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What is the antibody molecule of immunoglobulins?
Gamma globulin fraction of plasma.
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each immunoglobulin molecule is composed of what ?
4 chains- 2 light 2 dark of amino acids
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what serves as a UNIQUE antigen-binding sites?
Variable regions at the end of the chains.
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Major immunoglobulin
IgG
Defends against bacterial cells, viruses, and toxins; Activates complement.
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Major immunoglobulin
IgD
B cell activation
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Major immunoglobulin
IgE
Promotes inflammation and allergic reactions.
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Antibody actions:
React to antigens in 3 ways
- 1)direct contact- agglutination, percepitation, and neutralization of antigens.
- 2)activation of complement- can produce opsonization (making the antigen sticky so antigen can stick better), chemotaxis, inflammation, or lysis in target cells.
- 3)stimulation of changes- in areas that prevent pathogen spreading.
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what is a primary immune response?
when b or t cells become activated for the first time. after some cells stay as memory cells.
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What is another name for allergic reactions? and what is it?
Hypersensitivity reactions- excessive immune responses that may lead to tissue damage.
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What is an antibody dependent cytotoxic reaction?
Occurs when blood transfusions are mismatched
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what is an immune complex allergic reaction?
involve auto immunity
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what happens during allergic reactions?
mast cells(activated by B-cells) release histamine and seratonin
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what are the 4 types of transplants?
- Iso graph-Donor from identical twin.
- Autograph- Self (skin from one place to another)
- Allograph- from same species ( close matched donor)
- Xenograph-Different species
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