B lymphocytes and antibodies

Question 1

Interleukins vs interferons

Answer 1

between leukocytes vs interferes with viral replication

Question 2

Innate cytokines: IF- alpha, beta and gamma

Answer 2

Inhibit viral infections

When cells can sense that their ribosomes have been “taken over” by viruses, this triggers the release of alpha and beta cytokines

1. interferon binds ot receptors on cells around the infected cell and induce in them a change of gene expression often referred to as transient virus resistant state where their ribosomes are now difficult to take over. Non-specific response because acting on ribosomes
2. affects NKC’s in the blood that up regulate their ability to recognise changes to associate with virus infection and kill those infected cells before the infection has completed its cycle

Question 3

Innate cytokines: IL-1, IL-6, TNF-alpha

Answer 3

pro inflammatory (est bacterial infections) 
Wound healing and tissue repair: fibroblast proliferation, bone resorption, prostaglandin and collagenase synthesis, neuroendocrine effects

Question 4

Adaptive cytokines

IL-1

Answer 4

T cell activation

B cell activation

Question 5

adaptive cytokines

IL-2

Answer 5

T cell proliferation

NK cell activation

Question 6

adaptive cytokines

IL-4, IL-5, IL-6

Answer 6

B cell differentiation 
antibody class switching

Question 7

Adaptive cytokines

IFNgamma

Answer 7

Antiviral
Macrophage activation
NK cell activation
MHC up regulation

Question 8

Il-8

Answer 8

C-X-C motif (alpha chemokines)

Neutrophil migration

Question 9

Map-1, MIP-1alpha

Answer 9

c-c motif (beta chemokines)

Allergic inflammation

Question 10

Haematopoietic cytokines

G-CSF, M-CSF, GM-CSF

Answer 10

Lineage specific control

Question 11

Haematopoietic cytokines

IL-3 (multi-CSF)

Answer 11

proliferation of many lineages in bone marrow

Question 12

Haematopoietic cytokines

IL-5

Answer 12

Eosinophil growth and activation (allergy)

Question 13

Haematopoietic cytokines IL-7

Answer 13

Erythroblast and megakaryocyte growth

B cell ontogeny in bone marrow

Question 14

What is the purpose of Haematopoietic cytokines?

Answer 14

just like EPO signals for more RBC production when you’re at high altitude, HC’s stimulate increased WBC production for when you need them

Question 15

antibody structure

Answer 15

two identical light (constant and variable region) and heavy chains (3 constant and 1 variable)
Hinge region, disulphide bonds the CH2 domain has the ability to bind to some of the complement components
and the bottom part (CH2 and CH3) often called the FC region

Question 16

How do we label light vs heavy chain isotopes

Answer 16

light

• kappa
• lambda

Heavy

• mu
• gamma
• alpha
• delta
• epsilon

Question 17

What is the antibody class defined by?

Answer 17

by heavy chain 
IgM
IgG
IgA
IgD
IgE

Question 18

Ouchterlony electrophoresis

Answer 18

allows you to analyse different serums in the blood
put spots on blood on agar plate and proteins will separate according to charge , can see what type on immunoglobulin e.g. gamma the patient is missing
Rabbit anti-human antiserum added to central trough, get diffusion to form precipitation lines

Question 19

Antibodies around birth

Answer 19

from around 3 moths conception to about 8months post birth babe protected by maternal IgG
From one month post birth to 1 year babe’s IgG levels rise to 80% that of an adults
IgM levels start to increase a 7 months conception
IgA starts around 2 months old and takes a lot longer to get to adult levels

Question 20

Where are B lymphocytes active?

Answer 20

secondary lymphoid organs e.g. spleen tonsils

Question 21

b cell colonel activation

Answer 21

antigens pas through secondary lymphoid organs and select out B cells with high affinity for those antigens 
This binding leads to the first signal to the B cell to say you've recognised something the B cell then internalises that antigen and re expresses peptides derived from it on class II MHC 
Helper T cells do the co-stimulator conversation and various cytokines 
The B cell then proliferates and differentiates into effectors which secrete antibodies specific to the antigen that induced the response (plasma cells) 
And also a population of memory cells that replace the original naive B cell

Question 22

Why memory cells?

Answer 22

Have the same specificity and immunoglobulin as the original B cell but theres more of them they’re longer lived, they recirculate and ultimately repopulate all our secondary lymphoid organs
Less fussy about the helper signals they require so they can be activated more quickly and in a more sustained way

Question 23

Antibody effects: blocking and neutralisation

Answer 23

Attachment and entry (viruses, parasites)
Main protective effect of secretory IgA
Toxins (tetanus, diphtheria)
Immobilising bacterial flagella

Question 24

Other Antibody effects

Answer 24

Agglutination
- clumping to assist phagocytosis
Opsonisation = enhancement of phagocytosis
Antibody dependant cellular cytotoxicity
Complement activation

Question 25

Antibody dependant cell mediated cytotoxicity

Answer 25

enhancing ability of K (killer) cells to bind to target, because the antibodies attach the two together
K cells aren’t phagocytic but release granules from their cytoplasm that kill the cell that the antibodies are bound to

Question 26

Large granular leukocytes properties

Answer 26

1. killer cells, by recognising virus infected cells

2. finding antibody targets and bound to bad cells and killing the cells attached

Question 27

Complement activation

Answer 27

antibodies band to bacterial cell surface antigens which causes a shape change in the antibody, the CH2 domain then becomes accessible to a set of inactive complement blood proteins that assemble themselves around that CH2 domain, to make an enzyme that then acts on the central component of the complement cascade called C3, C3 is cleaved into two fragments C3a affects blood vessel permeability, the C3b fragment is very chemically reactive and covalently attaches to anything close by, supposedly bacteria.
C3b has two functions
1. it has a link to phagocytes through their CR1 receptor so it can enhance phagocytosis
2. relates fragments that attract neutrophils to the site e.g.C5a fragment
3. a place where the “late components” can aggregate and breach the bacterial cell surface membrane