L3.8 Adaptive Immunity – B Cells

Question 1

What is the M protein?

Answer 1

This is what the body recognises as foreign. M cell hairs move into the lymph system and encounter B cells and start the immune response

Question 2

Why do lymph nodes swell?

Answer 2

Swell due to clonal proliferation when B cells encounter M protein.

Pain is normal due to rapid expansion of the lymph node and stretching of the capsule.

No pain indicates gradual growth - cancer

Question 3

What is the process of forming the B cell?

Answer 3

Make heavy chain first, then light chain - heavy chain can be rearranged twice and light chain 4 times

Question 4

What is isotopic exclusion?

Answer 4

Only one type of light chain is utilised by a single B cell

Question 5

What are B1 and B2 cells?

Answer 5

• B1 Cells: act like an innate cell, made in fetal liver, important in first few weeks of life, provide unspecific antibodies for protection against LPS, role isn’t so important due to presence of breast milk
• B2 Cells: provide protection, from bone marrow

Question 6

What do follicular DC do?

Answer 6

Not from the immune system but pass antigens to the lymph nodes without processing them

Question 7

What is the helper for B cells?

Answer 7

CCR7

Question 8

What is hyper IgM syndrome?

Answer 8

Cannot make IgG, IgA or IgE - not getting help from B cells because they dont have CD40 ligand function. B cells cant undergo isotype switch. Patients have hyper IgM.

Question 9

How do antibodies change the effector function?

Answer 9

Alter the constant

Question 10

How can B cells change the use of the constant region of the heavy chain?

Answer 10

Interact with CD4 T cells