immune system- adaptive immune system section 3

Question 1

adaptive immune system is

Answer 1

last line of defence in system. last component of immune response to activate

Question 2

adaptive immune system consists of

Answer 2

• T cell and B cell lymphocytes
• both cells types are involved in elimination of antigens in our body
• part of immune system that ‘remembers’ past infections and provides long lasting immunity

Question 3

what are antigens

Answer 3

anything that elicits an immune system response in our bodies (bacteria, viruses, toxins)

Question 4

two components of adaptive immune system

Answer 4

• cellular immunity (mediated by cytotoxic T cells and protects against antigens in cells)
• humoral immunity (mediated by B cells and protects against antigens in blood)

Question 5

T cells are produced by…. and what does maturation do to them?

Answer 5

• hemopoietic stem cells in bone marrow, mature in thymus before they circulate in the body.
• maturation ensures T cells are functional and don’t attack their own cells (targeting of own immune system is cause of autoimmune disease)

Question 6

each T cell is born with a unique, randomly generated…

Answer 6

T cell receptor that recognizes specific antigen

Question 7

two main types of T cells

Answer 7

• helper T cells, characterized by presence of CD4 molecules on cell surface
• cytotoxic T cells, characterized by CD8 molecules on cell surface

Question 8

how do helper T cells function

Answer 8

bearing the CD4 molecule function by secreting cytokines that act to enhance other immune receptors

Question 9

two classes of Th cells

Answer 9

• Th1 cells : secrete cytokines that regulate immunological activity and development of a variety of cells
• Th2 cells: cytokine-screwing cells that act on B cells to drive their differentiation into plasma cells that make antbibody

Question 10

cytotoxic T cells

Answer 10

-Tc are cells that target specific cells by inducting apoptosis
-as long as antigen recognized by cell, each Tc cell can kill more than one target cell: very effective

Question 11

how are T cells activated

Answer 11

• dependent on antigen presenting cells (monocytes, B cells that display fragments of antigens that they have phagocytose on their surfaces)
• displayed antigens are recognized by T cell receptors
• binding of these receptors triggers activation of T cells

Question 12

what do T cells undergo

Answer 12

• activated T cells undergo CLONAL PROLIFERATION and DIFFERENTIATION
• they differentiate into either EFFECTOR CELLS which participate in fighting off current infection, or MEMORY cells which help protect against further infections, contribute to long term immunity

Question 13

B cells, where do they develop

Answer 13

• produced by hemopoietic stem cells of bone marrow and STAY there to mature

Question 14

B cells

Answer 14

• each born with a unique B cell receptor that recognizes specific antigen
• B cell receptor is identical to antibodies that differentiated B cells will produce

Question 15

B cell activation

Answer 15

• bind to free floating antigens with their B cell receptors and phagocytose the antigen
• digest it and display fragments on their cell surface
• effector helper T cells bind to fragments and secrete cytokines which activate B cell

Question 16

what do activated B cells under go?

Answer 16

• activated B cells undergo clonal proliferation (multiple rounds of cell division) and differentiation
• differentiate into antibody secreting plasma cells and memory cells

Question 17

functions of antibodies?

Answer 17

1. neutralization
2. agglutination
3. precipitation
4. complement activation
5. promotes phagocytosis

Question 18

neutralization

Answer 18

antibodies neutralize the pathogen or toxin by physically covering up the dangerous parts so it cannot damage body cells

Question 19

agglutination

Answer 19

having multiple binding sites allows for antibodies to clump antigens together making them easier to eliminate via phagocytosis

Question 20

precipitation

Answer 20

agglutinating soluble antigens can cause them to crash out of solution making them easier to eliminate via phagocytosis

Question 21

complement activation

Answer 21

binding antibodies triggers activation of the complement cascade (soluble mediator proteins)

Question 22

promotes phagocytosis

Answer 22

being covered in antibodies makes it easier for phagocytic cells to identify antigens

Question 23

primary response

Answer 23

• immune systems first exposure to a pathogen
• symptoms are relatively severe because it takes time for initial adaptive immune response to a pathogen to become effective

Question 24

secondary response

Answer 24

upon re-exposure to same pathogen, secondary adaptive immune response is generated: STRONGER AND FASTER because population of memory less were generated in primary response
- eliminates a pathogen before it can cause significant tissue damage
- basis of immunological memory, protects us from getting diseases repeatedly from same pathogen

Question 25

active vs passive immunity

Answer 25

1. active development of an immune response in the infected individual 2. passive transfer of immune components from immune individuals to a non immune one

Question 26

artificially acquired active immunity

Answer 26

vaccines. - vaccine is a killed or weakened pathogen that leads to development of immunological memory without causing many symptoms.

Question 27

inactivated vaccines

Answer 27

generally used when pathogens that have been killed but still retain antigens so they can be recognized and used for immune response

Question 28

live attenuated vaccines

Answer 28

when pathogen involved doesn't trigger an immune response when introduced in a killed or inactivated state

Question 29

toxoid vaccines

Answer 29

include a toxin molecule that has been modified to be harmless but still elicits an immune response against the toxin

Question 30

inherited immunodeficiencies

Answer 30

arise from gene mutations that affect specific components of the immune response, resulting in a weakened immune system. - most serious: "severe combined immunodeficiency disease" which affects both B and T cells

Question 31

human immunodeficiency virus/AIDS

Answer 31

-HIV is transmitted thru sex fluids and blood. invades and destroys CD4 T cells - loss of T cells result in AIDS.

Question 32

autoimmune disease

Answer 32

- diseases attack their own bodies - examples: rheumatoid arthritis, lupus erythematosuc

Question 33

blood typing

Answer 33

- following an infusion of incompatible blood, erythrocytes with foreign antigens appear in the bloodstream and trigger an immune response. - antigens from plasma cells attach to antigens on the plasma membrane of infused RBC and cause them to stick together

Question 34

hemolysis

Answer 34

as erythrocyte clumps degrade, their hemoglobin is released into the bloodstream. hemoglobin travels to kidneys which are responsible for filtration of blood. if too many hemoglobin are released- overwhelm kidneys = kidney failure

Question 35

ABO blood typing

Answer 35

designates presence/absence of A and B glycoproteins. - people with A antigens on their erythrocyte membrane surfaces are designated blood type A and vice versa - ppl with both are blood type AB - people with neither are designated blood type O - genetically determined

Question 36

individuals with type A blood have...

Answer 36

pre formed antibodies to the B antigen circulating in their blood plasma. these antibodies (anti-B-antibodies) will cause angulation and hemolysis if they ever encounter erythrocytes with B antigens

Question 37

individuals with type AB blood have...

Answer 37

pre formed antigens to both

Question 38

people with O blood lack...

Answer 38

antigens A and B on their erythrocytes, but both pre formed anti a and anti b antigens circulate in their blood plasma

Question 39

Rh D antigen

Answer 39

Rh positive , those who lack it are Rh negative