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Nonspecific host resistance and the immune response
Specific host response
57
Microbiology
Undergraduate 1
04/28/2012

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Term
Resistance
Definition
ability to fight off a disease
Term
Susceptibility
Definition
lack of resistance
Term
Antigen
Definition
any substance self or foreign that can initiate an immune response to an immune competent host
Term
T-dependent antigen
Definition
an antigen that requires assistance from T-helper lymphocytes to synthesize antibodies
Term
T-independent antigen
Definition
an antigen that does not require assistance from T-helper lymphocytes to synthesize antibodies
Term
Hapten
Definition
an incomplete antigen; an antigen that cannot initiate or trigger an immune response on its own
Term
Antibody
Definition
a specific protein synthesized in response to a specific antigen
Term
B-lymphocytes/ B-cells
Definition
provide humoral immunity by synthesizing antibodies
Term
T-lymphocytes/ T-cells
Definition
provide cellular immunity by synthesizing group of proteins called lymphokines
Term
Vaccine
Definition
an antigen that protects the host from a specific disease
Term
Opsonin
Definition
any substance that increases the chance of phagocytosis
Term
Nonspecific defense of the host (first line of defense)
A. Constitutional factors:
1.species resistance:
Definition
a. Birds are resistant to B.anthracis, while cattle are susceptible
b. humans get mumps but cats and dogs do not
c. Humans are susceptible to plaque (Yersinia pestis) while groung squirrels are resistant
Term
2. Race or strain resistance
Definition
a. African blacks are more susceptible to tb and malaria than whites
b. whites are more susceptible to influenza, diphtheria, and gonorrhea than blacks
Term
3. Gender (male or female)
Definition
female mice were 20% more resistant to typhoid fever than male mice
Term
4. Nutrition
Definition
dietary protein and vitamins are directly related to protection from microbial disease. Proteins are used to make healthy new tissues and serum proteins, while vitamins are essential for various metabolic activities
Cabbage--> susceptibility to salmonella reduced
Term
5. Age
Definition
very young ( have not developed immunity Igg) and very old (size of thymus shrinks) are more susceptible to disease
Term
B. Physical and Chemical factors:
1. Skin
Definition
a. low moisture (fungus)
b. lactic acid
c. low pH (3-5)
d. lysosyme (G+ bacterial growth protection(sweat glands) and sebum (sebaceous glands)
Term
2. Mucus membrane
Definition
it covers the entire digestive, respiratory, and reproductive tracts
Mucus membrane (goblet cells)

mucus + cilia

throat
↓ ↓
Stomach (pH 1.5-2.5)out (cough/sneeze)
Term
Which pathogenic organisms can penetrate through healthy mucus membrane and cause disease?
Definition
1. Treponema pallidun
2. Mycobacterium tuberculosis
3. Streptococcus pneumoniae
Term
C. Cellular factors
1. Inflammation
2. Phagocytosis
Definition
( leak of fluirds) a process of vasodilation caused by bradykinin which triggers mast cells to release histamine. Histamine is a vasodilator.
Term
Phagocytic cells:
1.Wandering phagocytic cells
Definition
a. lymphocytes
b. monocytes
c. neutrophils
Term
2. Fixed phagocytic cells (histiocytes) ***
Definition
a.Kupffer's cells: found in liver and spleen (after 120 days go to liver and turn into biliruben)
b. Alveolar macrophages: found in lungs
c. Microglial celss of CNS
Term
Steps of phagocytosis?***
Definition
1.chemotaxis or adherence (attachment)
2.ingestion (by means of phagosome)
3.intracellular digestion
4.exocytosis (release of microbial debris)
Term
3. Natural killer cells
Definition
1. adherence
2. ingestion (psudopodium)
3. formation of phagosome
4. lysosome ->fusion
5. phagolysosome
6. destruction of microbes, release of microbial debris
Term
D. Microbial factors
Definition
Normal flora competes with pathogenic intruders for food and space
Ex: E.coli (lg instestine)
Lactobacillus (vagina)
Term
Specific defenses of the host (second line of defense)
The immune response (antibody+antigen)
A. Actively acquired
Definition
host makes his/her own antibodies(long term)
1. Natural: host comes in contact with unintentional exposure to antigen and produces his/her antibodies
2.artificial- giving antigen intentionally, same as vaccine (long term)
Term
B. Passively acquired
Definition
someone else makes the antibodies for a host (short term immunity)
1.natural- mom to fetus
2.artificial- horse to a baby
Term
The duality of immune system:
A. the humoral (antibody-mediated immune response)
Definition
-protects host at body fld level (blood plasma, lymph, mucus, and other body secretions)
-only B-cells are directly involved, which produce antibodies
-Effective mostly against bacteria, bacterial toxins and viruses
Term
B.The cell immediate immune system
Definition
-active at cellular and blood level -T-cells are involved which produce lymphokines (a group of proteins that regulate the activities of other cells) -antibodies are not involved -effective mostly against intracellular bacteria, virus and fungi
Term
Characteristics of antigen or immunogen
Definition
1. should have molecular wt of 10,000 Daltons or more
2. should be solubilized by body enzymes (ex.pneumococcal antigen is more antigenic in mice than in man)
3. foreigness: must possess nonself epitopes (specific area to which an antibody attaches)
4. Molecular complexity
Term
Antigen elimination curve:
Definition
1. 90% of the antigen is removed withing 10-20 minutes by phagocytosis
2. long catabolic phase
3. remaining antigen molecules are opsonized and eventually phagocytized
Term
B and T-lymphocyte production
Definition
Bone marrow
(multipotent stem cell/hemocytoblast)

rubriblast (RBC)
myaloblast (granulocytes)
monoblast (monocyte)
megakaryoblast (thrombocytes)
Lymphoblast
↓ ↓
Thymus Galt
↓ ↓
T-lymphocyte ↓
(gut associated lymphoid
tissues: spleen, appendix, lymph nodes, Pyer's Patches)

B-Lymphocyte
Term
Function of B-lymphocytes?
Definition
provide humoral immunity by making antibodies
Term
Function of T-lymphocytes?
Definition
provide cellular immunity
Term
The antibody response
Definition
A. Microbial antigen is processed by a phagocytic cell
B. Antigen is presented on the surface of phagocytic cell, now called Antigen Presenting Cell (APC)
C. Stimulation of a B-lymphocyte by an APC results in the production of plasma cells (produce antibodies during primary response) and memory cells (produce antibodies during secondary response)
Term
Function of Thymus gland?
Definition
where T-lymphocytes mature
Term
What is the purpose of booster shot?
Definition
to enhance number of memory cells
Term
***Primary immune response:
Definition
1. Long catabolic phase/processing
2. low abtibody titer
3. Lesser avidity towards antigen (not strong bonding)
4. Antibodies are mostly IgM
5. Decrease in antibody titer is rapid
Term
***Secondary or booster or anamnestic immune response:
Definition
1. short catabolic phase
2. high antibody titer
3. higher avidity towards antigen
4. Antibodies are mostly IgG (immunoglobulin)
5. Decrease in antibody titer is gradual
Term
Structure of antibody:
Definition
-antibodies belong to a class of proteins called immunoglobulin (IgG)
-an antibody resembles the letter Y, which is made of four polypeptide chains- two heavy (H) and two light (L) chains
- The chains are joined together by disulfide bonds (2)
- Most of the antibody molecules is made up of a constant (C) regions, which are the same for all antibodies of the same class
-Both the H and L have sections located at the end of Y's arm called (V) regions which bind to specific antigens
Term
Class 1: IgG
Definition
A. most common antibody in human serum
B. found in blood, lymph and intestine
C. protect against circulating bacteria, viruses, neutralize bacterial toxins, and enhance phagocytic activity
D. protect fetus and the new born
E. appears in second immune response
Term
Class 2: IgM
Definition
A. found in blood and lymph
B. first to appear after antigenic stimulation
C. protects fetus and newborn, but cannot be transferred from mother to fetus through placenta
Term
***Class 3: IgA
(highest in body flds)
Definition
A. Found in body secretions such as tears, mucus, saliva, colostrum, and lymph
Term
Class 4: IgD
Definition
A. Found in blood and lymph
B. function unknown
Term
***Class 5: IgE
(bad for ppl, high level ppl keep epinephrine pen)
Definition
A. Found in blood (surface of mast cells)
B. Responsible for hypertensive response (mast cell->final destination->inflammation)
Term
Hypertensive allergic reaction:
1. T-helper or inducer cells (Th, T4)
Definition
-assist T-dependent antigen to produce antibodies
Term
2. T-suppressor cells (Ts, T8)
Definition
-stop antibody production
Term
3. Cytotoxic killer cells (Tk, TctL)
Definition
-destroy cancerous, tumor, and cells invaded by microorganisms; also responsible for graft rejection
Term
4. Delayed hypersensitivity T-cells (Td) (delayed allergies)
Definition
-responsible for allergies occurring several hours or days after contact; skin reactions as in tuberculin test
Term
Autoimmune diseases (humoral or cell medicated response against self-antigen)
Definition
A. Grave's disease
B. Rheumatoid arthritis
C. Systemic lupus erythematosus
Term
Grave's disease:
Definition
excessive thyroid hormone production when antibodies react with thyroid gland

Anti-thyroid
Term
Rheumatoid arthritis:
Definition
anti-chondrocytic antibodies
Term
Systemic lupus erythematosus
Definition
anti-nuclear antibodies
Term
B-cell deficiencies
Definition
Bruton's agammaglobulinemia (body cannot produce any antibodies at all)
Term
T-cell deficiencies:
Definition
A. AIDS
B. Nezelof's syndrome
Term
AIDS
Definition
T-4 cells
Term
Nezelof's syndrome
Definition
babies born without thymus
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