How do we eliminate pathogens that live outside cells

Question 1

what are the primary lymphoid organs

Answer 1

thymus and bone marrow, where immune cells are made

Question 2

what are the secondary lymphoid organs

Answer 2

where immune systems happen, these include all the lymph nodes, spleen and lots of lymphoid tissue such as payers patches in the gut, T and B cell conduct immune response in this tissue(adaptive response)

Question 3

what do people have

Answer 3

different number of lymphoid tissues

Question 4

describe how draining lymph nodes work

Answer 4

• Draining lymph nodes drain areas where they are near,
• The blood comes out of the circulation system with nutrient and oxygen in it and the liquid has to get back into the blood so it comes back down the lymphatic vessel through the lymph node then back to the thoracic duct. This acts as a drain as it drains the tissue, therefore anything that is infected goes to the lymph node

Question 5

what does the spleen do

Answer 5

• Spleen does this from the blood, it cleans the blood, therefore if you don’t have spleen you are vulnerable to blood diseases

Question 6

what stays in the secondary lymphoid for a long time

Answer 6

• T and B cell can stay in secondary lymphoid number for a long time without being used they are only activated when you have an infection which they detect from the tissue

Question 7

describe the basis of the immune response

Answer 7

• If you cut yourself PRR receptors on the cells of the innate immune system (such as macrophages) recognise the pathogens around and this causes inflammation and the innate immune response can keep the level of pathogens down and occasionally get rid of the pathogen on its own
• The inflammation gets a lot of fluid in the area and this allows more liquid to come out and forces liquid down the lymph nodes, this forces bits and pieces of pathogens to go down there and cells to go into the lymph nodes such as dendritic cells
• Dendritic cells crawl around the tissues and detect pathogens and pick up pieces of dead cell this causes them to become activated and mature so they no longer crawl around and they chop bits of protein up putting them on MHC class I and class II
• They go to the lymph node
• Try to find b and t cells that recognise these pathogens
• T and B cells that recognise the pathogens clonally expand

Question 8

what does the Body use to get rid of extracellular pathogens

Answer 8

• Use things in the body fluid to get rid of the pathogens such as
• antibodies
• complement proteins,
• phagocytosis
• antibodies
• antimicrobial peptides

Question 9

what are the extracellular spaces in the immune response

Answer 9

• blood
• lymph
• interstitial spaces
• epithelial surfaces

Question 10

what are the intracellular cell surfaces in the immune response

Answer 10

cytoplasmic and vesicular

Question 11

what are the cells that respond to the intracellular infection

Answer 11

– cytotoxic T cells,

• NK cells,
• T cell dependent macrophage activation are involved in killing the cell
• Once pathogen is in the cell than it is killed or it has something squirted at it is not repaired – stops the spread of the disease

Question 12

what is the humeral immune response

Answer 12

this is the immune response associated with body fluids

Question 13

what are the body humors

Answer 13

these are the body fluids

Question 14

what do B cells do to works

Answer 14

B cells make antibodies

- Antibodies stick to antigens – irritates the worm so much that it leaves

Question 15

describe the antibody structure

Answer 15

• Heavy chain has different types which leads to the different isotypes
• Only make 5 different types of antibodies
• FAB end bind to the antigens (variable region) -
• FC end bind to the heavy chain (constant region) – FC – fragment of crystalisation

Question 16

what are the two ends of the antibody

Answer 16

• FAB end bind to the antigens (variable region) -

- FC end bind to the heavy chain (constant region) – FC – fragment of crystalisation

Question 17

what are the heavy chain isotopes

Answer 17

U = Igm
Circle with pony tail = IgD
Gamma = IgG 
Alpha – IgA
Funny E – IgE

Question 18

what does the FC portion of the heavy chain do

Answer 18

the FC portion of the heavy chain dictates the function of the antibody such as is it secreted in the lungs, does it form a dimer

Question 19

what is the structure of the antibody isotopes

Answer 19

IgD, IgE, IgG – monomer
IgA – dimer
Pentamer – IgM

Question 20

what are the monomer antibody isotopes

Answer 20

IgD, IgE, IgG

Question 21

what are the dimer antibody isotopes

Answer 21

IgA

Question 22

what are the pentamer isotopes

Answer 22

IgM

Question 23

How many different antibodies are there

Answer 23

375 million

Question 24

What are the 5 basic things that antibodies need to do

Answer 24

• Neutralisation – prevent it entering cells
• Opsonisation - macrophages recognise the FC end of the antibody and when it sees a lot of FC it can eat it
• Agglutination – easier to deal with by cells – sticked together
• Antibody-dependent cell killing ADCC (by NK cells) – the FC portion of the antibody is reconised and then the NK kills the cell by squirting things at it
• Activation of complement – classical pathway

Question 25

POINTS TO REMEMBER

Answer 25

• each B cell makes a supply of a unique antibody
• each antibody recognises a different antigen
• we make millions of B cells
• SO we make millions of different antibodies

Question 26

IgA

Answer 26

• secrete grams of IgA into the gut

- every bacteria in the gut is covered in IgA

Question 27

IgM

Answer 27

• forms clumps and sticks things together

- first antibody that the plasma cell makes

Question 28

How does B cell activation happen

Answer 28

• Resting B cell,
• Antigen binds to B cell
• Activates B cell
• Activated T cell which help the activated B cells
• Form the plasma cell, for IgM
• Or form IgG, IgA, IgE

Question 29

How does the complements cascade work

Answer 29

• Proteins are activated in the blood and when they see bacterium and when they see antibodies bound to bacterium they become activated and form a complex that leads to the formation of the pore which pops the bacterium
• Our cells have proteins on the surface which inactivate the complement proteins

Question 30

what are super antibodies

Answer 30

• made next time that you are infected by for example influenza
• specials cells that take bits and pieces of influenza and hold it out to B cells that have already been activated by influenza, int he germinal centres they start to mutation the ends of the Y molecule so the FAB areas
• makes a few modifications and makes a better fit to the antigen
• if it is a better fit then it is given a growth factor and starts dividing producing daughter cells
• this happens in the germinal centres in lymph nodes and spleen

Question 31

what organisms invade outside of cells

Answer 31

Extracellular bacteria: 
Staph. Aures
Staph. Pyogenes 
Bordetella Pertussus
E. coli

Fungi

Helminths

Question 32

what are exotoxins

Answer 32

a toxin release by a living bacterial cell into its surroundings (eg Cholera)

Question 33

what are endotoxin

Answer 33

Lipopolysaccharide molecules associated with the outer membrane of gram negative bacteria (eg Neisseria Meningitidis)

Question 34

what are the components that make up the humeral immune response

Answer 34

B cells/Plasma cells

T helper cells

(macrophages)

Question 35

How does the humeral immune response work

Answer 35

step 1; the periphery

• Bacteria are engulfed by macrophages, the macrophages then display the surface antigens of the bacteria using MHC class II, it is now an antigen presenting cell (APC)
• T helper cells recognize the antigen displayed by the APC using T cell receptors, the APC then secretes Interleukin I
• The Th cell then produces interleukin II, which triggers T cell proliferation and formation of antigen specific receptors – it is an activated T cell

Step 2 lymph nodes

• B cells engulf the bacteria and display the surface anigens using MHC class II – it is now an APC
• Circulating activated T cells can now recognize the B cells using their antigen specific receptors
• The activated T cells dock with the B cells and releases cytokines that trigger B cell proliferation and differentiation into plasma cells
• The plasma cells can now secrete antibodies that are specific to the invading pathogen

Question 36

what is an antibody

Answer 36

Antibodies are glycoproteins produced in response to invading foreign particles

Question 37

what I need to know for the complement pathway

Answer 37

Complement proteins are a number of serum plasma proteins that circulate around the body
The C1 complement protein is activated by the antigen-antibody complex
This triggers the activation of the other complement proteins which trigger inflammation, opsonize bacteria and form the “membrane attack complex” (MAC)