15. Immunoglobulin isotypes Flashcards Preview

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Flashcards in 15. Immunoglobulin isotypes Deck (23):
1

Mature B cell surface

IgM and IgD

2

Mature B cell - differentiation into .. (location)

plasma cells that secrete Ig A, IgE , Ig G
Location: germinal centers of lymph nodes

3

Main antibody in ry (delayed ) response to an antigen

IgG

4

Most abundant isotype in serum

IgG

5

IgG function

1. Fixes complement
2. Crosses placenta (passive immunity in infants)
3. Opsonizes bacteria
4. Neutralizes bacterial toxins and virusesIgF structure

6

IgG structure

monomer

7

IgA function

prevents attachment of bacteria and viruses to mucous membranes

8

IgA structure

monomer in circulation
dimer when secreted (with J CHAIN)

9

IgA release into

secretions (tears, sallica , mucus) and breast milk

10

IgA - complement

does not fix it

11


IgA crosses epithelial cells by (also during secretion

transcytosis
picks up secretory component from epithelial cells before secretion --> protect the Fc portion from luminal proteases

12

Most produced antibody overall

IgA - but lower serum concentration

13

Antibody that produced in the primary immediate response to an antigen

IgM

14

IgM - complement and placenta

fixes complement but does not crosses the placenta

15

Beside in the blood, IgM is also found

the surface of B cells (as a receptor)

16

IgM structure

Monomer in B cells
Pentamer when sexreted
(J CHAIN)

17

antibody with the lowest concentration in serum

IgE

18

IgE function

1. Bind mast cells and basophils --> cross links when exposed to allergen mediating immediate (type 1) hypersensivity through release of inflammantory mediators such as histami
2. Immunity worms by activation eosinophils

19

• ___(IgG/IgA/IgE) is highest in serum while ___(IgG/IgA/IgE) is lowest in serum. ___(IgG/IgA/IgE) is the most produced antibody.

IgG, IgE, IgA

20

• Name four secretions in which immunoglobulin A can be found.

Tears, saliva, mucus, and breast milk (colostrum)

21

• What benefit is conferred by immunoglobulin M taking on a pentameric configuration?

Increased ability to trap free antigens out of tissue while the humoral response is evolving

22

• What is the function of immunoglobulin D, and where can it be found?

Function is unclear; surface of many B cells and in serum

23

A pregnant woman in her third trimester is exposed to a virus. Which immunoglobulin provides the fetus with passive immunity?

Maternal IgG crosses the placenta (IgM does not)