Immunoglobulin structure and fucntion Flashcards Preview

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Flashcards in Immunoglobulin structure and fucntion Deck (53)
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1

what are antibodies also termed as?

immunoglobulins

2

where are immunoglobulins present in?

Plasma, tissues, secretions and lymphatics

3

what is immunoglobulins a product of?

humoral immune system

4

what are immunoglobulins secreted by?

activated B cells

5

What are the five classes of immunoglobulin?

-IgG
-IgM
-IgA
-IgD
-IgE

6

what do these 5 classes of immunoglobulins do?

Provide recognition function and trigger effector functions

7

Describe the structure of an antibody molecule.

Consists of two heavy chains and two light chains. The hinge that connects the two heavy chains is disulphide bonds and non covalent interactions also hold chains together

8

what do both the heavy and Light chains have?

-variable region
-constant region

9

what does the Fab region stand for?

fragment antigen binding

10

what does the Fc region stand for?

fragment crystaliasble

11

Relate Fab and Fc regions to the dual function of antibodies.

-Recognition function- Binding to antigen via Fab arms
-Effector function- Clearance mechanisms via interaction of Fc with effector molecules

12

what are the two types of light chains?

-lambda
-Kappa

13

Do light chains in antibodies classes differ?

No -All antibody classes use these same light chains

14

what do the light chains fold up into?

2 globular domains termed VL and CL

15

What determines the class of antibody?

the heavy chains

16

Name the different heavy chains in the 5 classes.

IgG gamma heavy chain
IgA alpha heavy chain
IgM micro heavy chain
IgE. epsilon heavy chain
IgD delta heavy chain

17

what does the heavy chains fold up into?

-IgG , IgA, IgD into 4 globular domains and for IgM and IgE 5 globular domains

18

what is needed for antibody molecules to complete their effector function?

sugar attachments - oligosaccharides

19

With millions of different antigens, what do antibodies do (adapter molecules)?

produce small number of effector molecules

20

what was revealed when comparing sequences of different antibodies?

There were three hypervariable loops or CDRs (complementarity determining region) in each V domain

21

what do hyper variable loops or CDRs form?

antigen binding site

22

What happens when Vh (variable heavy domain) and Vl (variable light domain) are paired?

their 6 CDRs create the antigen-binding site

23

what makes up the antigen binding site?

6 Hypervariable regions or complementarity determining regions (CDR) - 3 in VH and 3 in VL

24

how does the antigen binding site and antigen bind?

Complementarity of 3D structures

25

What is the most abundant Ig in plasma?

IgG

26

Describe the shape of the IgG?

Y shaped:
2 HC of 50 kDa, 2 LC of 25 kDa

27

What are the subclasses of IgG?

4 subclasses - IgG1, IgG2, IgG3, IgG4

28

what is IgG efficient at triggering?

complement and phagocytosis via Fc receptors

29

what characteristic does IgG have that no other Ig's have?

Only Ig class to cross placenta from mother to foetus - protects baby in first months of life

30

what is IgG a predominant antibody of?

Secondary response