11- Lymphocytes

Question 1

What are the 3 major types of lymphocytes?

Answer 1

1) B cells
2) T cells
3) NK cells

Question 2

B cells are responsible for what

Answer 2

Antibody production

Question 3

What is the role of T cells?

Answer 3

Regulate adaptive immunity and are responsible for cell-mediate immune responses

Question 4

What is the job of NK cells?

Answer 4

Play a role in innate immunity

Question 5

Where do B cells and T cells develop?

Answer 5

B cells: bone marrow, bursa, payer’s patches
T cells: thymus

Question 6

What are the important surface antigens of B cells and T cells?

Answer 6

B cells: immunoglobulin
T cells: CD2, CD3, CD4, or CD8

Question 7

What are the secreted products of B cells and T cells?

Answer 7

B cells: Immunoglobulins
T cells: cytokines

Question 8

What are the antigen receptors for B cells and T cells?

Answer 8

B cell: BCR-immunoglobulin
T cell: TCR- protein heterodimer associated with CD3, CD4, or CD8

Question 9

List the steps in the maturation of lymphocytes

Answer 9

• Commitment: common lymphoid progenitor
• Proliferation: Pro-B/Pro-T cells, failure to express pre-antigen receptor= cell death
• Pre-B/Pre-T Ag receptor expression: expresses one chain of Ag receptor, failure to express Ag receptor= cell death
• Ag receptor expression: immature B/T cells express complete Ag receptor

Question 10

Explain positive and negative selection

Answer 10

Positive: moderately reacting with self-MHC
- weak reaction with self MHC= cell death

Negative: not reacting strongly with self antigen
- reacting strongly with self-antigens= cell death

Question 11

List different types of T cells based on their antigen receptors, accessory molecules and functions

Answer 11

T cells with alpha/beta receptors and CD4 accessory molecules (Helper T cell)
- functions: Helper 1, helper 2, helper 17, regulatory, or memory

T cells with alpha/beta antigen receptors and CD8 accessory molecules (cytotoxic T cell): cytotoxic, regulatory, or memory

Question 12

Name three major receptors of NK cells and explain their roles in the activity of NK cells

Answer 12

Ly49: binding of MHC class 1 leading to inhibition of target cell lysis
CD16 (ADCC): Binding on target cell leading to target cell lysis
NK2GD: binding of MICA/MICB leading to target cell lysis

Question 13

Lymphocytes all look the same but can be differentiated by what?

Answer 13

Their characteristic cell surface molecules

Question 14

These cell surface molecules are classified by what system?

Answer 14

CD (cluster of differentiation) system

Question 15

Lymphocytes possess antigen receptors plus the ______ ________ molecules required to activate the cell.

Answer 15

Signal transductions

Question 16

Lymphocytes also possess receptors for _______, __________, and _________.

Answer 16

Cytokines, immunoglobulins, and complement

Question 17

The collection of cell surface molecules on a lymphocyte is called its _____________.

Answer 17

Immunophenotype