Chapter 6: Interections of Cell-Mediated and Humoral Immunity

Question 1

When is an antigen an immunogen?

Answer 1

When it activates the immune system along with an inflammatory response.

Question 2

What must happen before lymphocytes can interact with the antigen they have been programmed to recognize?

Answer 2

The antigen must first be processed and displayed on the cell membranes of APCs (macrophages or dendritic cells)

Question 3

What are the two most common APCs (Antigen Presenting Cells)?

Answer 3

Macrophages and Dendritic Cells

Question 4

What allows B lymphocytes to bind and respond to intact antigen?

Answer 4

Immunoglogins and antibodies

Question 5

What happens when a B lymphocyte receptor (Ig or Ab) bind to an intact antigen?

Answer 5

1) They process the antigen and display it on their surface in conjunction with MHC Class II proteins.
2) They proliferate with help from activated T helper cells.
3) Best Ag binding cells survive to produce Ab

Question 6

True or false: T lymphocytes can respond to a foreign antigen alone.

Answer 6

False; they require an APC-processed antigen to trigger them to respond

Question 7

What are the surface antigen recognition receptors on T cells? What do they recognize?

Answer 7

TCRs

Question 8

What does a CD4+ T cell TCR recognize?

Answer 8

Ag/MHC II

Question 9

What does a CD8+ T cell TCR recognize?

Answer 9

Ag/MHC I

Question 10

What type of T cell is a CD4+?

Answer 10

Helper cell

Question 11

What type of T cell is a CD8+?

Answer 11

Cytotoxic cell

Question 12

Of which type of T cell are Th1, Th2, Th17, and Treg subsets?

Answer 12

Helper T cells (CD4+)

Question 13

What stimulates CD4+ helper T cells to help the proper Ab-producing B cells proliferate, differentiate into plasma cells, and make Ab?

Answer 13

Presentation of the processed (phagocytosed, lysosomally digested, surface display with MHC II carrier) by macrophages/APCs

Question 14

How are B cells chosen for proliferation and antibody production?

Answer 14

They bind the foreign Ag, internalize it, and dispay pieces with MHC II on their surfaces to stimulate

Question 15

What do CD8+ cytotoxic T cells do when activated by recognizing Ag with MHC I on the surface?

Answer 15

Destroy the infected cells by perforin or apoptosis

Question 16

True or false: CD8+ T cells can eliminate infected cells, cancerous cells, or transplanted cells.

Answer 16

True

Question 17

Why is there a “lag phase” of a week or more after contact with an antigen before an immune response is demonstrated?

Answer 17

This is the time needed to process the antigen and allow lymphocytes to respond.

Question 18

Which types of T cells regulate the immune system by establishing a balance between promoting and inhibiting immune responses?

Answer 18

T helper cells (CD4+)

Question 19

T cells that are ready to respond in the future to a past attacker.

Answer 19

Memory T cells

Question 20

True or false: The HIV virus attacks and destroys cytotoxic T lymphocytes.

Answer 20

False; it destroys helper T cells

Question 21

On which chromosome are HLA/MHC genes located?

Answer 21

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