Immunology-Immune Response

Question 1

What happens during the primary response?

Answer 1

Antigen taken up by dendritic cell (DC)

interact with antigen via innate PRR or random pinocytosis

digested to peptides within DC, some then bind to MHC

expression of CD80

only DC can activate naive T cells

undigested antigen interacts with B cells that express antibody to bind to it

clonal expansion

IgM antibody secretion

Question 2

What is the first antibody that is produced in any immune response?

Answer 2

IgM

Question 3

What happens in a secondary response?

Answer 3

Lag period is short (3 days as opposed to 7-10)

production of antibody much greater (occurs with IgG, IgM remains similar)

high level of IgG remains and maintained for years

Question 4

What are the major effector functions of the four classes of antibodies?

Answer 4

Blockade and agglutination: IgA (mucosal secretions), IgG (inside body)

Promotion of phagocytosis:FcR of phagocytes stims cell activation and triggers opsonization

Degranulation of mast cells/eosinophils: IgE production

Fixation of complement

Question 5

IgM

Answer 5

primordial antibody

low affinity for antigen

binds antigen well

main function: target for complement activation

Question 6

IgG

Answer 6

major antibody in plasma

several different subclasses

some fix complement, act to opsonize targets for phagocytosis

major class of antibody linked to eosinophil degranulation

Question 7

IgE

Answer 7

small quantities in plasma

mainly produced at mucosal sites

binds to mast cells and triggers degranulation

target for eosinophils

Question 8

IgA

Answer 8

functions outside body in secretions

low concentration in plasma

prevent attachment of bacteria, fungi, viruses, and toxins to mucosal epithelium

doesn’t fix complement