The immune System

Question 1

list the cells and molecules involved in the immune response (8)

Answer 1

1. antigen-recognition lymphoid cells
2. Granulocytes
3. Macrophages
4. Dendritic cells
5. Natural Killer Cells ( B & T Lymphocytes)
6. Cytokines
7. Accessory molecules
8. other molecules

Question 2

what are the antibody-mediated immunity (humoral) components

Answer 2

1. Complement: lysis of bacteria and some viruses, opsonin, increase in vascular permeability, recruitment and activation of phagocytic cells
2. Coagulation system: increase vascular permeability, recruitment of phagocytic cells, B-lysin from platelets which is a cationic detergent
3. Lactoferrin & transferrin: compete w/bacteria for iron
4. Lysozyme: breaks down bacterial cell walls
5. Cytokines: various effects

Question 3

what is Hematopoiesis

Answer 3

the process to produce immunce cells

Question 4

define stem cells

Answer 4

an unspecialized cell that can divide w/o limit and under specific conditions differentiate into specialized cells

Question 5

name the 2 main pathways from which Leukocytes are derived from?

Answer 5

stems cells in the bone marrow can be from ;

• Lymphoid lineage
• Myeloid lineage

Question 6

define Antibody (Ab) and how does it work

Answer 6

blood protein that is produced in response to and countering a specific antigen. they chemically bind to a substance that the body recognizes as foreign

Question 7

define Specificity

provide an example

Answer 7

a specific defense that is activated by 1 specific antigen

• T and B Lymphocytes has receptors that bind only 1 specific antigen

Question 8

define Antigen(Ag)

Answer 8

molecule or molecular structure that may be present on the outside of a pathogen and can be bound by an antigen-specific antibody

• Ag= antibody generator

Question 9

define Tolerance (property of immune system)

Answer 9

the immune system tolerates “normal” (self) antigens and only attacks foreign (nonself) antigen

failure of immune system to maintain tolerance levels leads to autoimmune diseases

Question 10

what is the 2nd line of defense

Answer 10

• nonspecific, innate
• cell derived like phagocytosis, complement proteins, interferons, inflammation, fever

Question 11

what are the cellular components of the Cell-Mediated Immunity

Answer 11

• Neutrophil: phagocytosis and intracellular killing which leads to inflammation and tissue damage
• Macrophages: phagocytosis and intracellular killing,
  
  • extracellular killing of infected or altered self targets, tissue repair, antigen presentation for specific immune resposne
• NK & LAK cells: kill virus infected and self targets
• Eosinophils: kill certain parasites

Question 12

what do hematopoietic stems cells give rise to?

Answer 12

red blood cells (erythorcytes)

Question 13

where do the cells of the immune system derive from?

Answer 13

pluripotent stem cells in the bone marrow

Question 14

define Versatility

Answer 14

the immune system ability to attack any antigen at any time

due to large lymphocytes diversity in the body each which have large populations and respond to a different antigen

Question 15

what are the 4 properties of immunity?

Answer 15

• specificity
• versatility
• memory
• tolerance

Question 16

what is the 1st line of defense?

Answer 16

• nonspecific, innate
• physical barriers like the skin, mucous membrane and chemicals

Question 17

define Memory (property of immune system)

Answer 17

lymphocytes remember antigens that they have encountered

• During initial response to an antigen the lymphocytes undergo repeated cell divisions which produce 2 types of cells;
  
  • activated lymphocytes: attack antigen invader
  • memory cells: remain inactive until exposed to the same antigen

Question 18

what are the 2 types of immune responses

Answer 18

1. cell-mediated immunity (CMI): response produced by T cells
2. Antibody-Mediated (Humoral) Response: response produced by B cells

Question 19

define Immunology

Answer 19

the study of our protection from foreign macromolecules or invading organisms and our response to them

Question 20

in a diagram show totipotent stems cells all the way to the specific type of cells they can produce

Answer 20

Question 21

what are precursor cells

Answer 21

unspecialized cells that can differentiate into various types of specialized cells in the body

Question 22

what is a progenitor cell

Answer 22

cells that are descendants of stem cells and can differentiate to form one or more types of cells

Question 23

what is the name of the process in which lymphocytes are produced? where are they stored

Answer 23

lymphopoiesis,

stored in the lymphoid tissues, organs and areas or red bone marrow

Question 24

List the 2 types of T Cells and their function

Answer 24

• CD4+ T Helper Cells (T_H)
  
  • Function: stimulate function of T & B cells. B cells must be activated by T cells before they can produce antibodies
• CD8+ cytotoxic T Cells (T_C)
  
  • function: attack foreign cells or cells infected by viruses. primary cells involved in CMI
    
    • T_S: T suppressor cells are a regulatory subset of CD8+ T Cells. inhibit function of T & B cells

Question 25

what are the organs that are associated with the immune system called? And how are they further separated

Answer 25

lymphoid organs * primary lymphoid organs or * secondary lymphoid organs

Question 26

what are the primary lymphoid organs?

Answer 26

site where lymphopoiesis, site where lymphoid cells proliferate, differentiate and mature to immune-competent cells in the absence of antigenic stimulation large at birth and they atrophy w/age progression * Thymus: where the T cells mature * Bone marrow: B cell maturation in humans * Bursa of fabricius: site of B cell maturation in birds

Question 27

what are the secondary lymphoid organs

Answer 27

lymphocytes made functional in secondary lymphoid organs. organs are small and poorly developed at birth and grow progressively w/age * Lymph nodes * spleen * Mucosal associated lymphoid tissues (MALT)

Question 29

List the agents in the 1st line of defense

Answer 29

* skin * mucous membrane * hair in the nose * cilia in the upper respiratory tract * saliva * gastric juice in the stomach * perspiration (sweating) * urine * sebum

Question 30

what are **_cytokines_**

Answer 30

small secreted proteins or chemicals released by cells to trigger/regulate the innate and adaptive immune response.

Question 31

what does the **_immunological surveillance_** _include?_

Answer 31

* Natural Killer (NK) Cells: directly kill tumor cells w/help of interferon , IL-2 * cytotoxic T Cells: also directly kill tumor cells * Cell-mediated T Cells (effector T Cells) that produce and release lymphokines * macrophage activation factor that activates marcophage * Gamma interferon & interleukin-2 that activate NK * Tumor necrosis factor (cachectine)

Question 32

list the different types of cytokines (4). How are they named?

Answer 32

cytokines are the general name * lymphokines: cytokines made by lymphocytes * monokine: cytokines made by monocytes * chemokine: cytokines with chemotactic activities * interleukin: cytokines made by one leukocyte that act on other leukocytes

Question 33

explain the events in phagocytic defense

Answer 33

1. chemotaxis of the phagocyte to microbe 2. adherence 3. ingestion 4. fusion of vesicles (lysosomes) 5. killing of microbes by enzymes and other chemicals 6. elimination (exocytosis)

Question 34

what are **_opsonins_** and what are their function

Answer 34

molecules that bind to bacteria and phagocytes they increase phagocytosis by 1000x through process called **_opsonization_**

Question 35

explain how opsonins attach to bacteria cells

Answer 35

* Opsonization begins when complement molecules C3b, iC3b or C4b attach to the surface of the bacteria * those molecules have a strong affinity for macrophagic CR3 & CR4. * when the complement molecules bind to the receptors it allows the phagocytic cell to engulf the bacteria

Question 36

Can **_complements_** be considered part of the innate immunity or adaptive immunity? Explain?

Answer 36

Complement can be considered part of the innate immunity because its role in inflammation, phagocytosis, and bacterial killing. It can also be considered part of the adaptive immunity because it can be activated by bacterial invasion as well as reactions between antibody and antigen

Question 37

how does the **_complement system_** work

Answer 37

1. attracts phagocytes to site of injury/infection (chemotaxis) 2. enhances phagocytosis of antigen:antibody complex 3. destroys target plasma membrane 4. stimulates inflammation by enhancing histamine release by mast cells and basophils. this increase local inflammation and accelerated blood flow 5. enzymatic system of serum proteins that are made of 9 components (C1-C9) which sequentially activated by classical pathway or alternative pathway 6. **_membrane-attack complex_** which is made up of terminal complement components which assemble to form membrane spanning hydrophilic pore which damage the membrane

Question 38

what are **_Toll-like receptors?_** How do they function?

Answer 38

TLR are transmembrane receptors that are associated with the innate immune response Function: they are pattern recognition receptors (PRR) that detect potential harmful pathogens and turn on a response to appropriately deal with pathogens. the response is usually the expression of cytokines

Question 39

how many TLR do humans have?

Answer 39

12. they each specialize in a different response to a pathogen

Question 40

what are **_interferons (INF)_**

Answer 40

a set of proteins that are released by viral infected cells, in vivo, which then react with uninfected cells so those cells can be resistant to infection from virus

Question 41

list the different types of interferons (IFN) in humans

Answer 41

* alpha interferon * beta interferon * gamma interferon

Question 42

what is inflammation?

Answer 42

a protective mechanism that is intended to get rid of the organism that cause the cell injury as well as to prevent the consequence of the injury such as necrotic cell and tissues