Innate and Adaptive Immunity

Question 1

what are cytokines?

Answer 1

proteins that alter the behaviour of other cells

Question 2

what are chemokines?

Answer 2

proteins that attract other cells

Question 3

what are the chemokines and cytokines, what are they made by and what do they do?

Answer 3

inflammatory mediators and are made by activated epithelial cells and are secreted and diffuse into the lamina propria.
they make the epithelia more permeable so things like phagocytes can migrate - all but RBCs can get in

Question 4

what does the bioconcave shape of the RBCs mean?

Answer 4

the cell can bend so can get through small spaces.

increased cell surface to volume ratio to increase chance of gas exchange.

Question 5

what are the two aspects of the innate and adaptive immune system?

Answer 5

humoral (dissolved) and cellular

Question 6

what are the humoral aspects of the innate immune system? what do they do? Tynwald Is Legendary For All Cool Thinkers!!

Answer 6

transferrin and lactoferrin - deprive microbes of iron
interferons - inhibit viral replication
lysozyme - breaks down peptidoglycan in bacterial cell walls
fibronectin - oponises bacteria and promotes their phagocytosis
antimicrobial peptides
complement - cause destruction of microbes directly or with the help of phagocytic cells
TNF-alpha - suppresses viral replication and activates phagocytes and natural killer cells

Question 7

what are the complement proteins, what do they do, when can they be used and what enhances the effect of them?

Answer 7

C1-C9.
system marks pathogens for destruction by covalently binding to their surface.
They can be used immediately after infection begins.
antibodies enhance the effect of complement activation

Question 8

what is the importance of the innate immunity implied by?

Answer 8

rareity of inherited deficiencies in innate immune mechanisms.
considerable impairment of protection when they deficiencies do occur.

Question 9

what are the cellular components of the innate immune system? what do they do? Boats Enemies Nock No More

Answer 9

basophils and mast cells - allergic response
eosinophils - anti-parasite and allergic response
natural killer cells - recognise and directly induce apoptosis in virus-infected/abnormal cells
neutrophils - phagocytic and anti bacterial (have several lobes to their nuclei)
macrophages and monocytes - phagocytosis and antigen presentation to lymphocytes (nuclei fill cytoplasm).

Question 10

what is phagocytosis enhanced by?

Answer 10

coating of antibodies or complement to render it recognisable as foreign (opsonisation)

Question 11

what is phagocytosis?

Answer 11

active engulfment of particles into a phagosome.

phagosome + lysosome (lysozyme inside) = digestion

Question 12

what is the 1st event of an inflammatory response? what can it be used for?

Answer 12

arrival of neutrophils

marker of acute inflammation

Question 13

what do mast cells do?

Answer 13

release inflammatory substances from granules (heparin and histamine)

Question 14

how do natural killer cells induce apoptosis in abnormal cells?

Answer 14

pump proteases through pores they make in the target cells

Question 15

what happens with the granules once the neutrophil is activated? how are neutrophils phagocytic?

Answer 15

unable to synthesis more granules once activated so once they have been used up the neutrophil dies.
bacteria binding to neutrophil receptors induces phagocytosis and microbial killing (lots of receptors for lots of different bacteria)

Question 16

features of macrophages?

Answer 16

phagocytose microbial cells and damaged/unwanted cells. Release a variety of cytokines.
are long lived
generate more lysosomes as needed.
act as professional antigen presenting cells

Question 17

what are the humoral aspects of the adaptive immune system and what do they do?

Answer 17

cytokines - promote the differentiation and proliferation of lymphocytes and natural killer cells.
perforin - released by T killer cells and destroys cell walls
antibodies - protect host by neutralisation (prevents binding to epithelia), opsonisation and complement activation (enhances opsonisation and lysis)

Question 18

what are the cellular components of the adaptive immune system and what do they do?

Answer 18

T cells:
T helper - become activated when CD4 binds to a specific antigen on the complex of an antigen presenting cell. Once activated, clones itself to form T helper cells and T memory cells. Activates B cells and macrophages.
T killer - releases perforin when cell is already infected to kill the infected cells.

B cells - divide to form plasma cells and memory cells when activated by T helper cells and release cytokines. Plasma cells produce specific immunoglobulin (antibodies) for non-self antigens

Question 19

what is opsonisation?

Answer 19

the coating of a microorganism by antibodies/complement to render it recognisable as foreign by phagocytes, thus enhancing phagocytosis.

Question 20

the main differences between innate and adaptive immune systems

Answer 20

I - present from birth, A- arises from exposure to microbes
I- non specific, A- specific pathogen immunity
I- Not enhanced by 2nd exposure, A - enhanced by 2nd exposure
I- No memory, A- Acquires memory, memory cells
I- Poorly effective without adaptive response, A- poorly effective without innate immunity

Question 21

what happens once the antigen is eliminated?

Answer 21

B and T cells undergo apoptosis. residue of B and T = seeding of memory cells

Question 22

what is the process of adaptive immune response?

Answer 22

clonal selection 
clonal expansion
differentiation to effector cells (T helper, cytotoxic T lymphocytes, plasma cells)
elimination of antigen
T and B cell apoptosis
seeding of memory

Question 23

what are the speeds of each type of immunity?

Answer 23

innate = quicker
adaptive = slower however lasts much longer

Question 24

what are antigens?

Answer 24

molecules that elicit a specific immune response when introduced into the tissues of an animal

Question 25

what does clonal selection do?

Answer 25

induces proliferation and increase effector cell frequency

Question 26

what are the receptors on T cells?

Answer 26

T cell antigen receptor

not membrane bound antibody but distinct molecule

Question 27

what are the receptors on B cells?

Answer 27

surface immunoglobulin

membrane bound antibody, produces immunoglobulin, some released and some expressed on the surface.

Question 28

what is the first barrier to infection and how does it protect?

Answer 28

epithelia. 
produces natural antibodies.
may posses motile cilia.
rapidly renewable
produce cytokines and chemokines
may produce mucins from goblet cells