Microbiology Test #4 (Immunology)

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Immune response to innocuous materials: Allergy (asthma)
Anti-self immunity: Autoimmunity (M.S)
immune responses to transplaned tissue: Graft rejection
defects in immune responses: immunodeficiency
treatment of immune diseases: immunosuppression
immunotherperutic interventions: immunoregulation
all the mechanisms used by the body as protection against envieomental agents that are foreign: Immune system
All the foreign enviornmental agents including microbes such as bacteria, viruses and fungi are collectively called: Antigens
True/False All foreign environmental agents are antigens.: False. There is a size restriction and it must elicit some immune response.
1st line of defense (non-specific immunity): Any structures, chemicals or processes that PREVENT pathogens'ENTRANCE to the body. (skin and mucous membraneS)
The skin is the 1st line of defense but it defends by two major layers. What is one and its fxn.: Dermis
-contains collagen (giving skin strength to avoid open wounds and therefore portals)
The skin provides both chemical and physical components of defense what are its 2 main chemical defeneses: 1.) Sweat
- salt inhibits growth
-Lysozyme- destroys cell wall

2.) Sebum (sebaceous glands)
-skin less likely to tear
- lowers pH= inhbit growth
The mucous membrane is part of the __________ line of defense. It lines ALL body cavities and consists of ____ distinct layers.: 1st line of defense;
2 layers

-epithelial: thin outer layer. ALL ALIVE! continously sheds.
Microbial Antagonism is also part of the first 1st line of defense: normal microbiota help protect the body by competing with potential pathogens.
-Normal flora secrete antimicriobial substances.
-Stimulate second line
-provide host with vitamins
other first-line defense: lacrimal glands- bathe the eye and salt inhibits growth
The second line of defense against pathogens includes components of...: blood
Blood components -Plasma -Serum -Formed elements: -Plasma: Mostly water contains elecrolytes, dissolved gasses and proteins
-Serum: plasma - clotting factor
-formed elements: cells and fragments in plasma.

In other words plasma is seperated into serum and formed elements
3 forms of formed elememts are (recall formed elements are cellular structures suspended in plasma): 1.) erythrocytes- (RBC) Carry oxygen ad Carbon dioxide in the blood.
2.) Platlets- blood clotting
3.) Leukocytes- involved in defending the body against invaders. (2 kinds)
Leukocytes (white blood cells) can be broken down into 2 groups. what are they and how are they distinguished.: 1.) Granulocytes

2.) Agranulocytes

by the prescense of granules.
the 3 types of granulocytes all stain differently. How?: Basophils- Stain under basic conditions (blue)
Eosinophils- Stain red under acidic conditions.
Neutrophils- stain under neutral conditions (lilac)
recall: What are the three types of granulocytes? Of the three which can phagocytize cells (nonspecific)?: Eosino"phils" Baso"phils" Neutro"phils".

Neutrophils and Eosinophils CAN phagocytize.
Besides phagocytosis what else are basophils not capable of that both eosinophils and neutrophils are?: they can leave blood vessels. (Very important)
Agranulocytes are broken into two types: lymphocytes and monocytes
Agranulocytes are mostly involved in which aspect of the immune system?: Specific immunity.
Lymphocytes are: Agraunolcytes that are involved in specific immunity (B cells and T cells)
Monocytes are: A type of agranulocyte that leaves the blood to mature into a MACROPHAGE.
Monocytes, Eosinophils and Neutrophils all can leave the blood system and phagocytize throughout the body a process called: diapedesis
Macrophages are made from ________. They can either be ___________ or _________.: Monocytes.
they can either be mobile or fixed
Fixed macrophages commonly reside in organs such as: lung, liver or in the nervous system
Lab Analysis of leukocytes -increased eosinophils indicates: Allergies or parasitic worm infection
lab analysis of leukocytes -increase in leukocytes and neutrophils: bacterial disease
lab analysis of leukocytes - increase in lymphocytes (realize these are agranulocytes): Viral infections
the second line of defense is responsible for all of the following: -Phagocytosis
-extracellular killing (diapedesis)
-nonspecific chemical defense
-inflammation
-fever
How are host cells safe from their own phagocytes: -Phagocytes attack cells with some characteristic on bacterial surface (flagella or cell wall component)
Opsonins: such as compliment and antibodies provide signal to the phagocyte (not host).
Extracellular killing is different from phagocytosis. Only two leukocytes engage in E.C killing they are...: Eosinophils (granulocyte) and Natural killer cells (lymphocytes-agranulocytes)
Eosinophils kill by extracellular killing. Normally they defend against.... by...: Parasitic helminths (worms)by secreting a toxin. therefore when eosinophils count goes up parasitic infection is probable.
Natural killer lymphocytes kill by extracellular killing. Particularly they defend against... by....: Viral infections by secreting toxins on to the surface of the virus or TUMOR.
Nonspecific CHEMICAL (not cellular) defenses (4 of importance): -Lysozyme
-Complement
-Interferon
-Defensins (?)
Complement activation results in...: lysis of the foreign cell.
What is the MAJOR benefit of Complement system: It is already naturally present in the blood (does not have to be made).
There are two ways to ACTIVATE complement (since it is already present in the blood) they are...: Classic pathway= Antibody-Antigen complex

Alternate pathway= Non antibody-antigen complex

*MUST BE ACTIVATED*
Protein molecules released by host cells to NONSPECIFICALLY inhibit the spread of VIRAL infections: Interferons
Interferons are particularly effective against...: VIRUSES with genomes of RNA.
NONSPECIFIC response to tissue damage resulting from various causes: Inflammation
Inflammation causes 4 signs and symptoms they are...: Pain, redness, heat and swelling.
There are two types of inflamation. Which is beneficial and which is harmful? why?: Acute inflammation- is good. it causes vasodilation and gets more repair cells to the site quicker.

Chronic inflammation- is bad it can actually cause MORE tissue damage than already present.
when chemicals called PYROGENS trigger the hypothalamus to increase the body's core temperature: Fever
Pyrogens the chemicals that cause fevers come in various types including: -Bacterial toxins
-Cytoplasmic contents of bacteria caused by lysis
-Antibody-antigen complexes (as in complement)
- Interleukin-I
How EXACTLY is fever produced...: Interleukin (or other pyrogens) cause the hypohalamus to secrete PROSTOGLANDIN which resets the hypothalamus' thermostat.
Why do we feel COLD when we have a fever?: Because fever is accomplished by vasoconstriction of the blood vessels thus the body's core temperature goes up, but the perimeter has less blood volume (rendering it cold).
What are the benefits of fever?: -enhance the effects of interferons and phagocytes
-Inhibits microbial growth
REVIEW: what are the benefits (5) and disadvantages (3) of the immune system?: 1.) kills bactera
2.) kills cells infected with viruses or bacteria
3.)destroys viruses
4.)destroys toxins
5.)destroys cancerous cells

1.)allergies
2.)rejects transplated tissue
3.)sometimes mistakenly attacks itself (autoimmune)
What are 2 MAJOR funcitons of Macrophages? (recall these are specialized monocytes (agranulocytes)): engulf bacteria and protozoa.

1.) Present ANTIGENS
2.) Produce CYTOKINES.
How do macrophages kill pathogens.: 1.) engulf: the macrophage engulfs bacteria (phagosome).

2.) Digestion w/ lysomsomal enzymes.

3.) generation of oxidizing agents (peroxide) (phagolysosome)
Lysosomal enzymes (4): 1.) lysozyme-sugars
2.) proteases
3.) lipases
4.)nucleases
What causes phagocytic failure?: chemicals produced by the pathogen...

1.) Carotenoids- stops lysosome activity
2.) leukocidins-kill macrophages (causing pus)
3.) capsules- inhibits recognition and phagocytosis.
The UNIQUE 2 organisms that can become part of macrophages and inhibit fusion with lysosomes are: TB and Salmonella
The third line of defense is: specific immunity
the third line of defense is referred to as a "smart" system. what does that mean?: it has memory. Memory B cells make antibodies so that the body fights off infection easily the 2nd time.
What is an antigen?: A molecule that triggers a SPECIFIC immune response.
What are ome examples of structures that cause immune response in the human body?: Bacterial: cell walls, capsules, pilli, flagella

Viral, protozoan and fungal proteins.
Antibody structure: it is made of _________ polypeptide ___________ of which are identical they are known as the _________ or _______ chains. F(ab) is the _______________ fragment also known as an ____________. while the base of the antibody is F (___).: four polypeptides
two of which are identical
heavy chain
light chain
antigen recognition site
epitope
Fc
All ANTIBODIES for the SAME ANTIGEN have what common characteristic?: Fab- all have the same antigen recognition site (epitope).
The lymphatic system screens tissues for foreign antigens. what are the two classes of the system.: 1 (primary)- Thymus and Bone marrow (T cells and B cells)

2 (secondary organs)lymphnode, spleen, tonsils, appendix
History of blood cells (differentiation): All blood cells begin in the bone marrow before differentiation (stem cells). To differentiate some migrate to the thymus and become T cells. others remain and become b cells.
Lymph cells originate from ___________ .: Stem cells
As a secondary organ of the lymphatic system, the spleen does wnat: filters all foreign matter from the blood (bacteria, viral, toxins)
Along with the spleen are the tonsils and MALT which stands for _________ and dungtion to?: Mucosa associated lymphoid tissue. MALT includes the appendix and Peyer's patch (walls of small intestine). These physically trap particles and microbes.
Facts about B cells differentiate in ________ Found mostly in __________ very few found ____________ Major function ____________: Red bone marrow
Secondary organs
circulating in the blood
Secrete antibodies (some however do not secrete A.B)
Antibodies also called ___________ are secreted by __________ specifically which type __________.: Immunoglobulins
B cells
Plasma cells (cells that are actively fighting antigens)
Antibodies' epitopes bind to antigens with what bonds?: noncovalent; hydrogen bond
Antibody function (5): Activate complement- to make cells leaky

Stimulate inflammation

Agglutination- Aggregates cells

Neutralization- ppt the pathogen

OpsonizatioN- coding the pathogen to be more readily engulfed.
5 classes of antibodies: IgM- 1st to respond
IgA- secretions
IgG- main antibody
IgE- fights parasites/alergin
IgD
BCR- B cell receptor: receptors on the cytoplasmic membrane that recognize and tag antigens. Antigens must not be too small.
BCR- B cell receptors and specificity.: Each BCR is complimentary to only ONE antigenic determinatnt
T lymphocytes were produced from __________ in __________ and differentiated in _________. Their function is to act against (3 classes) of antigens.: Bone marrow stem cells
thymus
endogenous invaders, INTRAcellulat pathogens, abnormal body cells (cancerous cells).
There are three types of T-lymphocytes they are: 1.) Cytotoxic T cells
2.) T helper 1 cells
3.) T helper 2 cells
Cytotoxic T cells are distinguished by what glycoprotein: CD-8
Cytotoxic cells serve one function: to kill certain cells. What cells do they kill?: 1.) intracellular pathogenic cells
2.) abnormal cancerous cells.
Helper T cells are distinguishable from Cytotoxic cells in that their cell surface has what glycoprotein?: CD-4
What are the main 2 fxns of Helper T cells?: 1.) To regulate the activities of B cells and Cytotoxic T cells
2.) secrete soluble protein messengers called cytokines.
Soluble regulatory proteins that act as intercellular signals when released from certain body cells (T-Helper cells): Cytokines
3 Types of Cytokines are: Interleukins- signal among leukocytes

Interferons- antiviral proteins

Tumor necrosis factors- secreted by macrophages and T cells to kill tumor cells.
How is it that the antibodies (secreted by plasma cells) know not to attack host cells?: Clonal deletion theory- early in life the body "edits" lymphocytes to eliminate any self-reactive antibodies.
Major histocompatibility complex (MHC): Important in determining self from non self cells. they function to hold a piece of antigen so T cell can attack.
Two classes of MHC: Class 1: self molecule

Class 2: non-self molecule
There are two ways for antigen processing. What are they? why do they occur? what is different?: T cell independent and T cell dependent

When the antigen is too small T cell is needed. if the antigen is readily accesible (large) B cells can bind directly to make antibodies.
Recall that antigens can be processed in one of two ways T-dependent and T-independent. How does this occur?: APC (Antigen presenting cell) internalizes the pathogen and digests it. Then the MHC II antigen (non-self) is presented on the cytoplasmic membrane.
A humoral immune response is mounted against what type of pathogen?: Exogenous (Extracellular)
B cells make up two classes they are: Plasma cells and memory b cells
Plasma cells are: Short lived cells that secrete antibodies.
memory b cells, unlike plasma cells are: long lived and DO NOT produce antibodies. Are avialable to initiate antibody production if the same antigen is encountered again.

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