TCR,BCR and MHC

Question 1

What is the importance of B cell receptor and T cell receptor diversity in antigen recognition?

Answer 1

B cell receptor and T cell receptor diversity allows the immune system to recognize a wide array of antigens.

Question 2

What are the two types of receptors expressed on T cells and B cells?

Answer 2

T cell receptor (TCR) is expressed on T cells and B cell receptor (BCR) is expressed on B cells.

Question 3

What is the Major Histocompatibility Complex (MHC)?

Answer 3

A set of proteins that help the immune system recognize foreign substances.

Question 4

What is significant about the genetic diversity of MHC genes?

Answer 4

MHC genes need as much diversity as TCR and BCR genes to present a wide array of antigens.

Question 5

What are the two classes of MHC proteins?

Answer 5

MHC Class I and MHC Class II.

Question 6

Which cells express MHC class I?

Answer 6

Almost all nucleated cells.

Question 7

Which cells express MHC class II?

Answer 7

B cells, macrophages, and dendritic cells.

Question 8

What is an antigen?

Answer 8

Any substance that may elicit an immune response.

Question 9

What are the three main types of antigens?

Answer 9

• Pathogen-derived antigens * Self antigens * Altered self antigens

Question 10

What are complementarity determining regions (CDRs)?

Answer 10

Regions in TCRs and BCRs that play a critical role in antigen recognition.

Question 11

What is the process of VDJ recombination?

Answer 11

The rearrangement of immunoglobulin genes to create diverse antibodies.

Question 12

How many V, D, and J segments are in the immunoglobulin heavy chain locus?

Answer 12

• Approximately 50 V segments * 27 D segments * 6 J segments

Question 13

What is the role of T helper cells (Th cells)?

Answer 13

Activate B cells and secrete cytokines.

Question 14

What do cytotoxic T cells (Tc cells) do?

Answer 14

Destroy infected cells using perforins and granzymes.

Question 15

What is the main difference between MHC Class I and Class II regarding peptide sources?

Answer 15

MHC I presents endogenous antigens, while MHC II presents exogenous antigens.

Question 16

What is the role of antigen-presenting cells (APCs)?

Answer 16

Process and present antigens on MHC to activate T cells.

Question 17

What is the significance of HLA alleles?

Answer 17

Variation of HLA alleles is beneficial for presenting different antigens.

Question 18

What occurs during T cell activation?

Answer 18

1. Cognate MHC-Peptide-TCR interaction 2. Co-stimulatory signals 3. Cytokine signals 4. Inhibitory signals

Question 19

What is the genetic location of the Human Leukocyte Antigen (HLA) region?

Answer 19

Chromosome 6.

Question 20

Fill in the blank: MHC Class I is primarily found on _______.

Answer 20

all nucleated cells.

Question 21

Fill in the blank: The genes HLA-A, -B, and -C code for _______.

Answer 21

MHC I proteins.

Question 22

True or False: MHC Class II is found on all nucleated cells.

Answer 22

False

Question 23

What is the function of CD4 and CD8 in T cell activation?

Answer 23

CD4 acts as a co-receptor for MHC II, while CD8 acts as a co-receptor for MHC I.

Question 24

What is the primary function of dendritic cells?

Answer 24

Specialized antigen-presenting cells that process antigens and activate T and B cells.

Question 25

What happens to endogenous proteins during antigen processing for MHC Class I?

Answer 25

They are degraded by the proteasome and presented on the cell surface.

Question 26

What role does the invariant chain (Ii) play in MHC Class II processing?

Answer 26

Guides MHC II to the lysosome for peptide binding.

Question 27

What is the role of TAP in MHC Class I processing?

Answer 27

Translocates peptides to the endoplasmic reticulum for binding to MHC I.