Types of Immune System Cells

Practice Questions

MCAT Biology › Types of Immune System Cells

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1

Which type of infection would a plasma cell be most effective in clearing from the human body?

2

Which of the following are NOT involved in cell-mediated immunity?

3

Which of the following immune cells is responsible for engulfing foreign bacteria, viruses, and parasites and presenting antigens to lymphocytes to initiate an immune reaction?

4

Hypersensitivity reactions occur when body tissues are affected by an abnormal immune reaction. The result is damage to normal tissues and clinical illness. A peanut allergy is an example of a hypersensitivity reaction, but there are three additional broad classes.

One class involves the abnormal production or deposition of antibodies. Antibodies are B-cell derived molecules that normally adhere to pathogens, rendering them unable to continue an infection. When antibodies are produced against normal tissues, however, disease can result. Figure 1 depicts a schematic structure of an antibody.

Antibodies can be divided into two peptide chains: heavy and light. Heavy chains form the backbone of the antibody, and are attached to light chains via covalent bonding. Each heavy and light chain is then further divided into constant and variable regions. Variable regions exhibit molecular variety, generating a unique chemical identity for each antibody. These unique patterns help guarantee that the body can produce antibodies to recognize many possible molecular patterns on invading pathogens.

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One of the functions of antibodies is to facilitate the phagocytosis of pathogens by macrophages or other professional phagocytes. Which of the following organelles is likely to be found in abundance in professional phagocytes, relative to most other cell types?

5

Which of the following cells is responsible for producing platelets?

6

Plasma cells and memory cells are categorized under which division of the immune system?

7

Which of the following is NOT an antigen presenting cell?

8

Which of the following molecules is not associated with the function of cytotoxic T-cells?

9

The thymus is responsible for producing which of the following immune cells?

10

Scientists use a process called Flourescent In-Situ Hybridization, or FISH, to study genetic disorders in humans. FISH is a technique that uses spectrographic analysis to determine the presence or absence, as well as the relative abundance, of genetic material in human cells.

To use FISH, scientists apply fluorescently-labeled bits of DNA of a known color, called probes, to samples of test DNA. These probes anneal to the sample DNA, and scientists can read the colors that result using laboratory equipment. One common use of FISH is to determine the presence of extra DNA in conditions of aneuploidy, a state in which a human cell has an abnormal number of chromosomes. Chromosomes are collections of DNA, the totality of which makes up a cell’s genome. Another typical use is in the study of cancer cells, where scientists use FISH labels to ascertain if genes have moved inappropriately in a cell’s genome.

Using red fluorescent tags, scientists label probe DNA for a gene known to be expressed more heavily in cancer cells than normal cells. They then label a probe for an immediately adjacent DNA sequence with a green fluorescent tag. Both probes are then added to three dishes, shown below. In dish 1 human bladder cells are incubated with the probes, in dish 2 human epithelial cells are incubated, and in dish 3 known non-cancerous cells are used. The relative luminescence observed in regions of interest in all dishes is shown below.

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When the body recognizes that cells have become cancerous, it responds in part by mobilizing cell-mediated killing of cancer cells. What cells are most likely responsible for this killing?

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