Lecture 45: B Cells and Antibodies

Question 1

B Cells are important because they make _______.

Answer 1

• Antibodies

Question 2

B Cells recognise whole (native) _____ _____ whereas T Cells recognise _____ / ___ Complexes.

Answer 2

• Protein Antigens

- Peptide / MHC Coomplexes

Question 3

B cells are activated by (only secrete antibodies if):

Answer 3

• Recognition of antigen

- CD4+ Help

Question 4

B Cells are _____ that develop in the ____ _____. They are the only cell that secretes ______. They express unique antigen receptors. Plasma cells are activated by __ Cells that secrete antibody. Memory B Cells provide ‘_____’.

Answer 4

• Bone marrow
• Antibodies
• B
• Memory

Question 5

Mature B and T Cells tend to be sent to the ___ ____.

Answer 5

• Lymph node

Question 6

Just like T Cells, B Cells express a unique __ ____ _______. This enables the recognition of a wide variety of antigens. BCR gene __________ is responsible for this.

Answer 6

• B Cell Receptor

- Rearrangement

Question 7

In The B Cell receptor has 2 _______ regions, changing them changes the antibodies _______.

Answer 7

• Constant

- Functions

Question 8

Three functions of antibody:

Answer 8

• Neutralisation
• Opsonisation
• Complement Activation`

Question 9

(Antibody) Neutralisation:

Answer 9

• Ab binds to surface strustures on microbes, blocking their ability to attach to host cells
• Binds to toxins preventing them from

Question 10

(Antibody) Opsonisation

Answer 10

• Bind to surface of pathogen
• Facilitates uptake by phagocytes
• Have two binding sites and can agglutinate bacteria, this increases the efficiency of uptake

Question 11

Isotype Switching:

Answer 11

• IGA / IGM etc.

Question 12

What’s so important as IgG?

Answer 12

• It’s the most abundant Ig class in blood.
• Opsonises / Neutralises
• Ig class that crosses placenta: provides ‘passive immunity’.
• Targets virus / bacteris

Question 13

IgA:

Answer 13

• Present in secretion such as tears, saliva, mucus, and breast milk
• Defence of mucous membranes, esp. gut
• Present in breast milk
• ‘Passive Immunity’

Question 14

IgE:

Answer 14

• Present in blood at low concentrations
• Immunity to multicellular parasites
• Allergic reactions
• e.g. Penicillin modifies cell proteins, IgE responses to penicillin-modified proteins can induce hives or anaphylactic shock

Question 15

IgD:

Answer 15

• Expressed on naive B Cells
• Together with IgM, acts as antigen receptor (BCR)
• Specific function unknown

Question 16

IgM:

Answer 16

• First Ig class produced after initial exposure to antigen.
• Expressed on naïve B cells
• Very effective inactivating Complement Function
• Targets extracellular bacteria
• Acts as antigen receptor (BCR)

Question 17

Humoral immunity is:

Answer 17

• Antibody mediated immunity

Question 18

The basic antibody unit is made up:

Answer 18

• 2 identical heavy chains, and 2 identical light chains

Question 19

IgG + IgA are important for….

Answer 19

• Passive Immunity