Study Guide Sheet 2 (pt1)

Question 1

Define immune response

Answer 1

A sequence of related host defense events beginning when a host encounters a substance as being “foreign” or “non-self” and leading to cellular and chemical defensive actions

Question 2

What are the general functions of lymph nodes?

Answer 2

Lymphatic fluid containing antigens and Antigen-Presenting Cells flows through lymph nodes where the antigens encounter and activate precommitted lymphocytes

responds to local or regional infections

Question 3

What are the general functions of the spleen?

Answer 3

Filters blood and traps blood-borne antigens

responds to systemic infections

Question 4

State the major characteristics of antigens, including the chemical nature and the typical minimal size.

Answer 4

• Substance appears foreign to host’s immune system
• Size – relatively large molecule, molecular weight usually greater than 10,000
• Chemical nature – usually protein with complex 3-D configuration

Question 5

What is an epitope?

Answer 5

The specific part of the immunogen that specifies or determines the exact antibody to be produced

Question 6

Define and characterize antibody: specificity

Answer 6

• Anitbody - antigen-specific proteins which bind to specific sites on antigens and assist in inactivating the antigen by attaching to it

Question 7

What is the chemical makeup of an antibody?

Answer 7

Chemical – glycoproteins (4-18% carbohydrate) produced/secreted by plasma cells

Question 8

What is the basic shape of an antibody?

Answer 8

“Y” shaped with Fab sites and FC region

Question 9

What is the specificity of an antibody?

Answer 9

Specificity - a macromolecule consisting of at least one monomer (one basic unit) comprised of two heavy chains and two light chains. Some classes are comprised of more than one monomer.

Question 10

What is the role of the Fab site?

Answer 10

The role of the fragment antigen binding site, is to actually bind to the epitope of the antigen in a “lock and key” fashion.

Question 11

How many Fab is/are there on one immunoglobulin molecule?

Answer 11

There are two fab sites per monomeric molecule

Question 12

Draw and label a detailed illustration of an immunoglobulin structure.

Answer 12

Draw it

Question 13

What are the major characteristics of and differences between innate and adaptive responses?

Answer 13

Innate is the Non-specific, general recognition and response to “foreign” substances, using physical and chemical barriers.

Adaptive is the Specific response to “foreign” substance using pre-committed cells and tissues

Question 14

Describe phagocytosis.

Answer 14

When a phagocyte, ingests an antigen or opsonized cell, and uses its lysosomal enzymes to digest it, resulting in debris.

Question 15

Describe the major histocompatibility complex protein classes, where each is found, and what are their roles?

Answer 15

• MHC 1 is a one chain amino acid protein that about every host cell in the body has. This differentiates “Self” from “non-self”
• MHC 2 is a two chain amino acid molecule that only APC’s carry (macrophages, dendritic cells, and B-cells). This allows them to present the epitope of an antigen to the T helper cells.

Question 16

What significant surface molecules are on T-cells ?

Answer 16

• CD3 – identifies mature T-cell
• CD28 – receives activation co-signal from CD80/86 molecule on APC
• CD40 – receptor binds with CD-40 molecule on B-cell
• LFA-1 – (Leukocyte Function-associated Antigen-1) – an adhesion molecule on T-cells

Question 17

What significant surface molecules are on B-cells?

Answer 17

• CD80/86 – when utilized as an APC
• CD40 - significant for binding with certain T-lymphocytes (Th)
• CD19, CD20, CD21 - used for identification

Question 18

Where do the T-cells mature and where do they concentrate after they mature?

Answer 18

T-cells mature in the thymus, and concentrate to the lymph nodes.

Question 19

Where do the B-cells mature & concentrate?

Answer 19

B-cells mature from bone marrow and concentrate in peripheral lymphoid tissues, e.g. spleen, mucosal-associated-lymphoid-tissue, lymph nodes, and bone marrow

Question 20

Define “Antigen-Presenting Cell”

Answer 20

A cell that can present the epitope of an antigen to a helper T-cell

Question 21

Where are macropahges found, and what significant surface components, and the major roles/activities do they have?

Answer 21

MHC II, presents the epitope of the antigen to the helper T cell

Question 22

Where are B-cells found, and what significant surface components, and the major roles/activities do they have?

Answer 22

• Found in the spleen, MALT, lymph nodes, and bone marrow.

- CD40, CD19/20/21, CD80/86 and MHC II (as APC)

Question 23

Where are Dendritic cells found, and what significant surface components, and the major roles/activities do they have?

Answer 23

Numerous MHC II’s.

Alveolar macrophage (lung)

Kupffer cells (liver)

microglial cells (brain)

Langerhans cells (skin)

interdigitating dendritic cells (lymph nodes and spleen most frequent APC)

Question 24

What are the primary cells involved in cell-mediated immunity response?

Answer 24

1. APC (macrophages and dendritic cells)
2. T-helper cells
3. CTL’s
4. NK cells

Question 25

What are the primary cells involved in humoral immunity?

Answer 25

1. APC (Macrophages, dendritic cells, and B-cells)
2. T-helper cells
3. B-cells to Plasma cells to produce: IgM, IgG