21) Which statement about the B cells’ abilities to produce antibodies is most accurate?

A) B cells wait to encounter an antigen and then copy it.

B) There are no B cells until an antigen is encountered.

C) There may be 100 million different B-cells, each producing a different antibody.

D) Most B cells are capable of producing any kind of antibody.

E) B cells don’t produce antibodies until they develop in the thymus.

22) Infected body cells can self-identify for destruction by the immune system by:

A) placing fragments of the infectious agent on their surfaces.

B) reshaping their membranes into a pattern that B cells recognize.

C) secreting hormones that stimulate macrophages.

D) releasing histamine.

E) becoming dendritic cells.

23) CD4 and CD8 T cells are likely to become active when they:

A) interact with B-cells.

B) travel through the spleen.

C) travel through lymph nodes.

D) are attracted by the inflammatory response.

E) dock with a dendritic cell with a matching antigen.

24) Why does producing a large “clone” of activated T cells also provide long-term immunity?

A) More cells are produced than necessary.

B) Some of the T cells can become B cells.

C) Some of the T cells become memory cells.

D) Leftover antibodies last a long time.

E) The cloned cells are stronger than the original cells.

25) What is the explanation for why B cells come in so many different types that can produce so many different antibodies?

A) The genome of B cells is much larger than other body cells.

B) B cells can recombine their genes with T cells.

C) B cells can recombine their genes with the pathogen.

D) B cells have gene fragments that can shuffle or recombine.

E) B cells can regulate shape to match the antigen.

26) Cells in the body that have been infected by a virus or bacteria are specifically killed by:

A) cytotoxic B cells.

B) mast cells.

C) dendritic cells.

D) regulatory T cells.

E) cytotoxic T cells.

27) Cells that help initiate the adaptive immune response by placing microbial antigens on their surfaces are generally referred to as:

A) helper T cells.

B) antigen-presenting cells.

C) B cells.

D) mast cells.

E) regulatory T cells.

28) Place the following in proper sequence regarding activation of the cell-mediated response: (1) dendritic cell migrates to lymph node, (2) T cells divide rapidly, (3) dendritic cell ingests pathogen, (4) CD4 and CD8 cells dock with dendritic cell, (5) dendritic cell presents antigen on its surface.

A) 1, 2, 3, 4, 5

B) 5, 3, 1, 2, 4

C) 3, 1, 5, 2, 4

D) 4, 3, 1, 5, 2

E) 3, 5, 1, 4, 2

29) Which of the following best describes the role of regulatory T cells?

A) Regulatory T cells are a kind of helper T cell that stimulates B cells.

B) Regulatory T cells are a kind of helper T cell that stimulates cytotoxic T cells.

C) Regulatory T cells help limit the immune system response.

D) Regulatory T cells stabilize and support memory cells.

E) Regulatory T cells stimulate natural killer cells to attack tumors.

30) A plasma cell is a cell that has differentiated from a:

A) B cell.

B) mast cell.

C) T cell.

D) dendritic cell.