Antibodies Flashcards

1
Q

What are the three secondary effector functions of antibodies once bound to antigens?

A

Opsonisation
Complement activation
Cell activation (e.g. mast cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which immunoglobulin category do antibodies fall into?

A

Gamma immunoglobulins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of bond holds together the chains in the immunoglobulin?

A

Disulphide bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is an immunoglobulin domain?

A

Internal intrachain disulphide bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What did scientists find when sequencing the amino acid sequence of the variable region on antibodies?

A

There are three hypervariable regions called the complementarity determining regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What part of the variable region of the antibody binds to the antigen?

A

The complementarity determining regions are found at the end of the variable regions and interact with antigens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What forces are involved in antibody-antigen binding?

A

THEY ARE ALL NON-COVALENT

Hydrogen bonding, ionic bonding, van der waals, hydrophobic interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define affinity.

A

The strength of the total non-covalent interactions between a single antigen-binding site and a single epitope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What equation shows affinity mathematically?

A

K = [Ab-Ag]/[free Ab][free Ag]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define avidity.

A

The overall strength of the multiple interactions between an antibody with multiple binding sites and a complex antigen with multiple epitopes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is antibody cross-reactivity? Give an example.

A

Antibodies that are produced in response to one antigen can cross-react and bind to a different antigen with a similar structure. E.g. cow pox and small pox

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are isotypes and allotypes of antibodies?

A

Isotypes vary in the constant regions – everyone has isotypes
Allotypes – polymorphic variables – some people have them others don’t

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do the different classes of antibodies (GAMED) differ?

A

They vary in the constant region of their heavy chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the two classes of light chain?

A

Kappa and lambda

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which immunoglobulin classes have subclasses and how many subclasses do they have?

A
IgG = 4 (in order of abundance – 1 is the most abundant)
IgA = 2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do the different subclasses vary?

A

They vary in the hinge region

17
Q

Describe the formation of secretory IgA.

A

Dimeric IgA is produced by plasma cells
It binds to the Poly-Ig receptor on the basolateral surface of the epithelia
This binding stimulates endocytosis
Once inside the cell, the poly-Ig receptor is cleaved and the dimeric IgA is secreted with the secretory component
The secretory component is derived from the poly-Ig receptor

18
Q

How can IgE activate cells?

A

It binds to the Fc (Fc-epsilon-RI) receptor on mast cells

When antigens bind to the IgE, which is attached to the mast cell, it stimulates degranulation

19
Q

Which two Ig classes are mainly responsible for activating complement?

A

IgM and IgG