MCP 34: Lymphoid I

Question 1

three immune defense mechanisms

Answer 1

physical/chemical barriers, innate (non-specific) immunity, acquired (specific) immunity

Question 2

physical/chemical barriers

Answer 2

tears, skin, mucus/cilia, commensals, gut acid

Question 3

commensals

Answer 3

bacteria that help fight off infection, our body doesn’t destroy them

Question 4

innate (non-specific immunity)

Answer 4

attacks anything that the body recognizes as foreign in a non-specific way, innate immunity is ancient

Question 5

cells that participate in innate immunity

Answer 5

neutrophils, eosinophils, macrophages (from monocytes), natural killer cells

Question 6

acquire (specific immunity)

Answer 6

T-cell immunity and B-cell immunity; much younger evolutionarily than innate immunity, sharks oldest animal to demonstrate acquired immunity

Question 7

cell-mediated (T-cell) immunity

Answer 7

mediated by T-lymphocytes, don’t secrete antibodies but recognize antigens through T-cell receptor, TCR interacts with MHC-I on infected cell

Question 8

humoral (B-cell) immunity

Answer 8

mediated by B-lymphoctes that originate from and mature in the bone marrow

Question 9

fetal B-cells

Answer 9

precursors may come from the liver

Question 10

mechanism of humoral immunity

Answer 10

mature B-cells leave bone marrow, has IgD antibody on membrane, and await activation by pathogen, once activated divide in plasma cells and memory cells, plasma cells release IgM antibodies into blood stream

Question 11

plasma cells

Answer 11

synthesize IgM antibodies that release them into blood

Question 12

memory cells

Answer 12

become a reservoir on activated B-cells in case the body becomes infected again

Question 13

antibodies

Answer 13

immunoglobins, 4 subunits; 2 light chains and 2 heavy chains held together by disulfide bonds, has a variable portion and a constant portion,

Question 14

variable portion of antibody

Answer 14

conference specificity to an antigen for a specific antigen,

Question 15

somatic recombination

Answer 15

random shuffling on DNA sequence that encodes for variable portion, occurs during B-cell development

Question 16

secondary response from memory cells

Answer 16

more rapid than primary response, magnitude of antibody release is greater, IgG antibodies released instead of IgM antibodies

Question 17

5 mechanisms by which antibodies neutralize a pathogen

Answer 17

1.) agglutination 2.) opsonization 3.) neutralization 4.) cytotoxicity 5.) complement activation

Question 18

agglutination

Answer 18

antibodies bind to antigens, forming aggregates and reducing the amount of free antigens

Question 19

opsonization

Answer 19

binding of antibodies to the microorganism stimulates phagocytosis

Question 20

neutralization

Answer 20

binding of antibody to microorganisms blocks their adhesion to cells and inactivates toxins

Question 21

cytotoxicity

Answer 21

antibodies adhering to the surface of macrophages and eosinophils and inducing them to liberate chemical agents that attack the surface of the antigen

Question 22

complement action

Answer 22

the binding of antibodies to the initial protein of the complement system triggers the complement cascade and causes cell lysis

Question 23

maturation of T cells

Answer 23

originate in bone marrow, mature in thymus

Question 24

major histocompatibility complexes

Answer 24

MHCs takes pieces from inside cell and displays them to the outside world

Question 25

MCH-I

Answer 25

all cells have these, if cells is infected with virus, piece of the virus will show up in MCH-1, targeted for destruction by killer T-cells

Question 26

MCH-II

Answer 26

found on antigen presenting cells (i.e macrophages), present material that has been brought by the APC (via phagocytoses), helper T-cells recognize as non-self and secrete interleukins, stimulates humoral immunity

Question 27

cytotoxin T-cells

Answer 27

killer T lymphocytes, CD8+ cells monitor MHC-1 molecule

Question 28

how killer T-cells kill cells

Answer 28

1.) lysis with perforin and granzyme 2.) activating Fas-mediated apoptosis

Question 29

helper T-cells

Answer 29

CD4+ recognizes MCH-II molecules on APCs, secretes interleukins that stimulates humoral immunity

Question 30

target of HIV infection

Answer 30

affects helper T-cells (CD4+ cells)

Question 31

IgD

Answer 31

monomer, extremely low amounts in serum

Question 32

IgG

Answer 32

monomer, largest percentage in blood

Question 33

IgM

Answer 33

pentamere, 5-10% in blood