Development of Lymphocytes

Question 1

MHC-I plus peptide binds to

Answer 1

MHC-I plus peptide binds to TCR on CD8 T cells

Question 2

MHC-II plus peptide binds to

Answer 2

MHC-II plus peptide binds to TCR on CD4 T cells

Question 3

Thymic Selection - effect on binding if +ve

Answer 3

Positive selection

Must bind MHC

Question 4

Thymic Selection - effect on binding if -ve

Answer 4

Negative selection

Must not bind self peptides

Question 5

Positive selection for B cells - function

Answer 5

Positive selection:

identifies immature B cells with completed antigen receptor gene rearrangement

Functional membrane Ig molecules (BCR) provide survival signals

Question 6

Receptor editing for B cells - describe

Answer 6

Receptor editing
If high avidity self-recognition - receptor editing changes BCR specificity
Reactivation of RAG genes produces new Ig light chain
If still reactive, rearranges λ light chains

Question 7

Negative selection - B cells

Answer 7

Negative selection

If still auto-reactive, immature B cells with high-affinity self-recognition die by apoptosis in bone marrow or spleen

Question 8

Steps after mature B cell stage is reached

Answer 8

Once the transition is made to the IgM+ IgD+ mature B cell stage, antigen recognition leads to proliferation and differentiation

Question 9

After the thymus what happens to naive cells

Answer 9

Naïve cells recirculate

primarily from blood to lymph nodes

Question 10

Activated B cells transform into

Answer 10

Activated B cells transform into Plasma cells
“Antibody factories”
also produce CD27+ memory B cells

Question 11

Lymphocytes organised into what - link to function

Answer 11

Organised mainly into Lymph Nodes

Architecture optimised to facilitate cellular interaction

Question 12

Key role of Spleen in antibody generation - describe

Answer 12

Key role of Spleen in antibody generation:

Splenectomy increases the risk of infection

Especially pneumococcal infection – recommend vaccination

Question 13

Lymphocyte function deteriorates with age - describe changes

Answer 13

Lymphocyte function deteriorates with age:

Both age of the cell and age of the individual
Telomere shortening
Change in functional attributes
Accumulation of CD57+ cells
CMV infection a key driver of immune senescence

Question 14

Lymphocytes - characteristics

Answer 14

Very powerful
Diverse
Defined in many dimensions
Active, mobile cells - many interactions
Actively dividing homeostatic populations
Key to protection against infection and cancer