Chapter 17 Part 2

Question 1

What is the difference between an antigen and an eptiope?

Answer 1

• An antigen is the region that antibodies will bind to so that it can signal the adaptive immune system.
• Epitopes are PARTS that will make up the antigen. This is the individual puzzle piece that an antibody will connect to.

Question 2

How many different epitopes does a single B or T cell recognize?

Answer 2

Each B or T cell recognizes only one epitope.

Question 3

When is antigen specificity set?

Answer 3

Antigen specificity is set during lymphocyte development.

Question 4

What is a naïve lymphocyte?

Answer 4

A naïve lymphocyte is a fully functional lymphocyte that has not been activated.

Question 5

What is an activated B cell called? What does an activated B cell do?

Answer 5

An activated B cell is called a plasma cell. Activated B cells produce antibodies (immunoglobulins) and are involved in humoral immunity.

Question 6

What are the major delays before the adaptive immune system is fully active?

Answer 6

The major delays include the time it takes for antigen recognition (matching with epitope), clonal expansion, and the production of a sufficient number of activated lymphocytes.

Question 7

What does a T cell use for its specific receptor?

Answer 7

Uses T-Cell Receptor (TCR) for its specific receptor.

Question 8

What does a B cell use for its specific receptor?

Answer 8

Uses surface-bound immunoglobulin (sIg), which is also known as the B cell receptor (BCR), for its specific receptor.

Question 9

How many different B cell and T cell specificities can be generated?

Answer 9

About 10^15 different B cell specificities and 10^18 different T cell specificities can be generated.

Question 10

How is a naïve B cell activated? What does the B cell do with the antigen after the antigen binds to sIg

Answer 10

• A naïve B cell is activated when its surface-bound immunoglobulin (sIg) binds to the antigen.
• After binding, the B cell internalizes the antigen and presents it to helper T cells. The B cell then differentiates into plasma cells, which produce antibodies

Question 11

What is the CD designation for T-independent B cells? What type of antigens are targeted by this new subpopulation of B cells?

Answer 11

• The CD designation for T-independent B cells is CD5+.
• CD5+ will target large polysaccarhide antigens.

Question 12

What is the full name of the protein that allows for T cell activation?

Answer 12

The full name of the protein is Major Histocompatibility Complex (MHC).

Question 13

What MHC type do Antigen presenting cells use to display an antigen?

Answer 13

Antigen-presenting cells use MHC II to display an antigen.

Question 14

How are CD 8+ T cells activated? What happens to the cell that activates a CD 8+ T cell?

Answer 14

• CD8+ T cells are activated when they recognize antigens presented by MHC I.
• The cell that activates a CD8+ T cell is typically infected or abnormal, and the CD8+ T cell kills the activated cell.

Question 15

How are CD 4+ T cells activated?

Answer 15

CD4+ T cells are activated when they recognize antigens presented by MHC II on antigen-presenting cells (APCs).

Question 16

What is immunological memory?

Answer 16

Immunological memory refers to the ability of the immune system to “remember” past encounters with specific antigens, resulting in a faster and more robust response upon re-exposure.

Question 17

What are some of the mechanisms that contribute to the development of memory?

Answer 17

Some mechanisms include the formation of memory cells, which can survive for years, and the more effective immune response upon re-exposure to the same antigen.

Question 18

What are the five different classes of antibody? Which one crosses the placenta? Which class is secreted in breast milk? Which classes are normally used in rapid antibody tests?

Answer 18

The five classes of antibodies are IgA, IgD, IgE, IgG, and IgM.
IgG crosses the placenta.
IgA is secreted in breast milk.
IgM and IgG are normally used in rapid antibody tests.

Question 19

What antibody class normally indicates you had an infection in the past? Which antibody class normally indicates you presently have that infection?

Answer 19

IgG normally indicates a past infection, while IgM normally indicates a current infection

Question 20

What are the mechanisms of antibody protection? Does an antibody kill by itself?

Answer 20

Antibodies recruit immune cells and proteins to attack antigens through mechanisms such as opsonization, agglutination/precipitation, neutralization, complement activation, and antibody-dependent cellular cytotoxicity (ADCC). Antibodies themselves do not kill but play a crucial role in coordinating immune responses.