Exam 1 (Lecture 2) - Cells and Antigen Binding

Question 1

List the 5 different types of WBCs, including where they originate, where they mature, general structure and function, the approximate percentage, and how long they circulate.

Answer 1

1) Basophil: originates in bone marrow; matures in bone marrow; granulocyte with segmented nucleus; parasite/allergic response; low %; short duration

2) Eosinophil: same as basophil

3) Neutrophil: originates in bone marrow; matures in bone marrow; granulocyte with segmented nucleus; bacterial/fungal infections; high %; short duration

4) Monocyte (macrophage): originates in bone marrow; matures in tissues; mononuclear; engulfs pathogens; low %; medium/short duration

5) Lymphocyte: originates in bone marrow; T cells mature in thymus and B cells mature in bursa (birds), bone marrow or Peyer’s patches; mononuclear play a role in adaptive immunity; medium %; long duration

Question 2

Explain what an endothelial cell is and a role it plays in the immune response.

Answer 2

An endothelial cell lines the walls of blood vessels (addressins). Express leukocyte adhesion molecules and provide and “address” that the leukocytes can recognize. Also play a role in cytokine production.

Question 3

List the primary and secondary lymphoid tissue and explain the basic difference (purpose/function).

Answer 3

1) Primary Lymphoid Organs: site of lymphocyte development/undergo clonal selection
- thymus
- bursa (birds)
- Peyer’s patchces
- bone marrow

2) Secondary Lymphoid Organs: sites where lymphocytes respond to antigens
- tonsils
- spleen
- lymph nodes
- Peyer’s patches
- bone marrow

Question 4

List 2-3 locations where lymphocytes are found in the body.

Answer 4

1) lymph nodes
2) spleen
3) bone marrow

Question 4

Describe how a B cell recognizes its antigen and draw a picture of a B cell bound to an antigen.

Answer 4

B cell displays antibody on its surface and the B cell receptor binds to the epitope of the antigen.

Question 5

Describe how and alpha-beta T cell recognizes an antigen.

Answer 5

They recognize antigens that are presented on MHC molecules.
- they can’t bind the antigen directly, so antigen HAS to be presented on MHC molecule

Question 6

Draw a picture of a CD4+ T-Helper cell and a CD8+ Cytotoxic T-cell bound to their antigens.

Answer 6

Question 7

Describe these different types of cells and how they compare to each other: leukocyte, lymphocyte, granulocyte, and mononuclear cells.

Answer 7

1) Leukocyte = broad term for all WBCs

2) Lymphocyte = one type of WBC

3) Granulocyte = granule-containing WBC

4) Mononuclear cells = cells with a round nucleus (lymphocytes are an example).

Question 7

Define passive immunity and active immunity. List an advantage and a disadvantage of each.

Answer 7

1) Passive = recipient did nothing to make the antibody; they just received antibodies
- works immediately, but no
memory and short-lived

2) Active = the individual responded to the antigen; they made their own antibodies and T-cells
- lag time; but there is a
memory

Question 8

Define and explain the role of antibiotics, tetanus antitoxin, and tetanus toxoid in the prevention and control of a disease such as tetanus.

Answer 8

1) antibiotics = kill the bacteria causing the infection

2) antitoxin = equal to antibody; will neutralize the toxin (blocks the action of the toxin); passive

3) toxoid = antigen (the inactivated toxin); stimulates active immunity

** in an unvaccinated animal = give the toxoid and the antitoxin

Question 9

Provide an advantage and disadvantage for both passive and active immunity.

Answer 9

Passive Immunity:
Advantage: Quick
Disadvantage: Short duration/no memory

Active Immunity:
Advantage: Has memory
Disadvantage: Long lag time (7-14 days)