Biology 27- MicrobiologyHomework questions on the immune systemDue May 7, 2008- 64 points

1. (15 points) Fill in the table with information about the immune system.

Type of cell or molecule

Is it considered part of the “innate” or “acquired” immune system?

Does it have immunological memory?

Does it target a specific type of invader and if so, what?

Neutrophils

B cells

NK cells

Cytotoxic T cells

Macrophages

Helper T cells

Mast cells

Tears

Skin

Normal flora

2. (4 points) Explain why each of the processes listed below is beneficial in the inflammatory response:

the presence of neutrophils

a rise in temperature

vasodilation

histamines

3. (10 points) We talked about the various cells of the immune system, and that they had molecules on their surfaces that were important to the function of that cell. The cells include neutrophils, macrophages, eosinophils, basophils (mast cells), natural killer cells, B lymphocytes, T lymphocytes, dendritic cells, and endothelial cells. For each of the molecules listed below indicate the cell on which the molecule is found. If the statement applies to more than one cell, indicate which ones.

___________________ MHC Class II molecules

___________________ an antigen-specific receptor that can be secreted as antibody

___________________ Fc receptors (that bind the constant region of antibodies)

___________________ toll-like receptors

___________________ CD4

___________________ MHC Class I molecules

___________________ an antigen-specific receptor that must recognize antigen that is presented by MHC Class II

___________________ receptors for complement proteins like C3a and C5a

___________________ cytokine receptors (general)

___________________ receptors for IgE

4. (10 points) Indicate whether the following statements apply to B cells, T cells, both or neither.

_____________________ produce and secrete antibodies

_____________________ can produce memory cells

_____________________ require contact with antigen-presenting cells for activation

_____________________ are derived from hematopoietic stem cells

_____________________ (their products) are effective against “free” antigens like circulating bacteria and viruses

_____________________ contribute to cell-mediated (cellular) immunity

_____________________ have antigen-specific receptors

_____________________ can respond to cytokines

_____________________ are found in lymph nodes and spleen

_____________________ mature in the thymus

5. (4 points) We talked about the clonal selection theory. Briefly answer the following questions.

a. “Clonal selection” applies to which type(s) of leukocytes?

b. In which part of the body do the earliest stages of lymphocyte development occur?

c. What event “triggers” the development of the cell to an activated cell?

d. In what part(s) of the body does this triggering event typically take place?

6. (10 points) Indicate the antibody isotype to which the following statements apply. If the statement applies to more than one, indicate which ones.

___________ in the blood, this antibody is primarily found as a pentamer

___________ most of the antibody in the blood is of this isotype

___________ this isotype is associated with allergy (hypersensitivity)

___________ this type is found primarily in the mucosa

___________can promote complement activation

___________ the predominant type produced in the primary response to antigen

___________ role is unclear; may participate in development or regulation

____________ has AT LEAST two antigen-binding sites

____________ binds to receptors on NK cells

____________ binds to receptors on mast cells

7. (6 points) Fill in the table about T cells.

Characteristic Helper T cell Cytotoxic T cell

Does the cell undergo develop in the thymus? (yes or no)Does the cell have an antigen-specific receptor? (yes or no)Which accessory molecule is expressed by the cell (CD4 or CD8)?Does the cell actually kill its target? (yes or no)

Does the antigen-presenting cell express MHC Class I or Class II? (indicate which one)What is its principal role in the immune response?

8. (5 points) Briefly answer the following questions. Think about the specific roles of these different immune system components in protection from infection.

If you had the immune deficiencies listed below, to what types of infections would you be more susceptible (bacterial infections, viral infections, fungal infections, all infections)

Deficiencies in B cells

Deficiencies in phagocyte activity

Deficiencies in complement

Deficiencies in cytotoxic T cell formation

Deficiencies in all T cell formation