Homework 1 Questions for Immunology

Despite its having been eradicated on a global scale, smallpox is presently considered a potential bioterrorism threat. Why? Use evidence to support your answer.

After eradication was achieved, smallpox vaccination programs largely ended. As populations continued to grow over time, an ever-increasing percentage of the human population remains unvaccinated and thus, is still susceptible to the disease.

What do the cells of the innate immunity system do in response to an antigen?

Engulf and destroy, induce inflammation

The hygiene hypothesis posits that there is a connection between environmental conditions and certain inappropriate immune responses. If you were a supporter of the hygiene hypothesis, what recommendations would you make to keep people healthier?

Expose children to more common antigens found in dirt and in the outdoors. Reduce use of antimicrobials.

True or False? The innate and adaptive immune responses work largely independently of one another.

False

Upon receiving immune serum as a treatment for a venomous snake bite, would the recipient be immune from future bites of the same species?

In the short-term, probably, as the serum contains protective antibodies against the venom. In the long-term, no, as serum treatment is a form of passive immunity. Passive immunity does not generate long-lived memory cells.

The innate immunity is mediated by what cells?

Macrophages, NK cells, neutrophils, mast cells eosinophils

Often, serendipity plays a role in significant scientific discoveries. In your own words, explain how serendipity led Pasteur to discover a cholera vaccine.

Pasteur developed the vaccine in chickens, which were in short supply. He challenged groups of chickens with cholera bacteria - some of which were previously exposed to an attenuated version of cholera bacteria. Only the previously exposed animals were protected from a new challenge, which led to the use of weakened pathogens as vaccines.

What do the innate immunity cells recognize?

Pathogen patterns

Why can't the cells of the innate immunity system control all infections alone?

Pathogens evolve escape mechanisms

What do the cells of the adaptive immunity system do in response to an antigen?

Produce antibodies, kill infected cells

What do the adaptive immunity cells recognize?

Specific epitopes

The adaptive immunity is mediated by what cells?

T cells and B cells

Why can't the cells of the adaptive immunity system control all infections alone?

Takes too long to develop

You have a friend unfamiliar with immunology, and he asks you the following question: "Why do I need the flu shot every year, but don't need an annual chickenpox vaccine?" As a student of immunology, how would you explain this discrepancy to your friend? Use evidence to support your answer.

The virus that causes the flu changes every year - as a result, a new flu vaccine must be prepared each year based on a predication of the most common forms of the virus likely to be encountered. Vaccines are specific in the type of pathogen against which they protect, and protection against one type does not guarantee protection against pathogens that are closely-related.

What is the central mechanism for establishing self-tolerance? a. Self-reactive T cells and B cells are killed during development. b. Immune cells that react to self-antigens are turned off when they recognize self-tissues. c.Individuals that have immune systems that respond to self-antigens do not survive to reproduce. d. Peripheral tissues have mechanisms to kill T or B cells that respond to them. e. Certain immune suppressive cytokines are maintained in tissues to dampen auto reactive immune responses.

a. Self-reactive T cells and B cells are killed during development.

Which of the following is TRUE about antigens? a. They are recognized by T cells or B cells. b. They must be microbial in origin. c. They are always proteins. d. They are always derived from pathogens. e. They usually cause cellular damage.

a. They are recognized by T cells or B cells.

Examine Figure 1-8. Which cells are MOST likely responsible for the intense response to Antigen A following a second exposure? a. Memory B cells b. Both memory T cells and memory B cells are responsible. c. T cells d. B cells e. Memory T cells

b. Both memory T cells and memory B cells are responsible

Which of the following cell types are lymphocytes? a. Macrophages b. T cells c. Mast cells d. Erythrocytes e. Neutrophils

b. T cells

How do memory cells develop?a. Upon reinfection, memory centers in the brain send signals to the bone marrow to induce T-cell and B-cell differentiation. b. T cells and B cells from the primary response persist and become reactivated. c. Innate cells modify their cell surface receptors to prepare for reinfection. d. Innate cells are trained to activate new T cells and B cells more quickly with secondary infection. e. T cells and B cells from the primary infection slowly mutate their receptors over time, priming themselves for the secondary response.

b. T cells and B cells from the primary response persist and become reactivated.

The following are parts of the humoral immune system: a. B cells. b. antibodies. c. All of the answers are correct. d. immunoglobulin. e. complement

c. All of the answers are correct.

Which of the following statements BEST differentiates innate and adaptive immune responses? a. Adaptive responses are slower and weaker than innate responses. b. Adaptive responses are required for effective immune responses, whereas innate responses are not required. c. Innate responses are stronger during the primary and less important during the secondary response, whereas adaptive responses are less robust during primary responses and stronger during secondary responses. d. Innate responses are slower and weaker than adaptive responses. e. Innate responses are weaker during the primary and more robust during the secondary response, whereas adaptive responses are stronger during the primary and weaker during secondary responses.

c. Innate responses are stronger during the primary and less important during the secondary response, whereas adaptive responses are less robust during primary responses and stronger during secondary responses.

What occurs when someone receives a tissue transplant from an unrelated individual? a. The host's lymphocytes enter the tissues and become suppressed. b. The host's lymphocytes that react to the tissue graft are deleted in the thymus. c. The host's lymphocytes enter the tissues and become activated. d. The donor's lymphocytes destroy the host's immune system. e. The donor's lymphocytes suppress the host's lymphocytes, allowing for graft survival.

c. The host's lymphocytes enter the tissues and become activated

Which is the BEST definition of "immunity"? a. The state of having been exposed to a pathogen repeatedly b. When the immune system is activated c. The state of being resistant to reinfection with a pathogen d. When physical barriers are not enough to prevent infection e. When an individual has never been exposed to a pathogen

c. The state of being resistant to reinfection with a pathogen

HIV disease is a(an) a. hypersensitivity disease. b. allergic reaction. c. immunodeficiency. d. genetic disorder. e. autoimmune disease.

c. immunodeficiency

Predict the outcome of being immunosuppressed as it relates to the development of cancer a. Immunosuppressed individuals are at higher risk of cancer because they bear a higher load of microbes that damage host tissues. b. Immunosuppressed individuals are at lower risk of cancer because they are more likely to contract infectious diseases. c. Immunosuppressed individuals are at higher risk of cancer because the immune system recognizes and destroys cancerous cells. d.Immunosuppressed individuals are at lower risk of cancer because cytokines produced by the immune system induce cancer. e. None of the answers are correct

c.Immunosuppressed individuals are at higher risk of cancer because the immune system recognizes and destroys cancerous cells.

Which of the following is the BEST example of a hypersensitivity reaction? a. T cells responding vigorously to the flu virus b. Anemia as a result of iron deficiency c. B cells failing to respond to HIV, allowing it to replicate out of control d. Inflammation of the airways in response to pollen e. T cells attacking the myelin sheath of nerves resulting in paralysis

d. Inflammation of the airways in response to pollen

Which of the following is TRUE? a. Vaccines cause autism. b. Vaccines cause diabetes. c. Vaccines cause obesity. d. None of the answers are correct. e. Vaccines cause cancer

d. None of the answers are correct.

Which of the following BEST describes chemokines? a. Chemical messengers that induce cell differentiation b. Adhesion molecules that bind to the inside of blood vessels c. Transcription factors that induce the expression of genes involved in cell adhesion d. Soluble proteins that recruit specific cells to an area e. Membrane receptors that detect the presence of soluble messengers in the environment

d. Soluble proteins that recruit specific cells to an area

Conditions in which the immune system attacks self-antigens are known as a. hypersensitivities. b. immune deficiency. c. None of the answers are correct. d. autoimmunity. e. neuroplasias.

d. autoimmunity

Which of the following is the BEST example of herd immunity? a. Geese and chickens are infected with different strains of influenza because they express different receptors on their cell surface. b. Certain populations of cattle are less susceptible to infection with encephalitis because of their genetic makeup. c. Once a certain threshold of individuals has been infected with a novel human pathogen, it is unlikely that any more will be. d. When infection spreads through a population, certain individuals generate stronger immune responses than others. e. A child infected with measles travels from Germany to the United States. Several babies contract the disease, but the outbreak is largely contained due to vaccinations.

e. A child infected with measles travels from Germany to the United States. Several babies contract the disease, but the outbreak is largely contained due to vaccinations.

Which of the following cell types is MOST commonly associated with recognizing antigens found inside of cells? a. Antibodies b. B cells c. TH cells d. Macrophages e. CTLs

e. CTLs

Which of the following diseases does NOT currently have an effective vaccine? a. Polio b. Diptheria c. Smallpox d. Chicken pox e. HIV

e. HIV

How are receptors encoded for adaptive immunity?

Rearranged gene segments

Many of the ideas raised by Ehrlich's conception of selective theory were true. Which of the following ideas (if any) were later shown to be FALSE? a. All the ideas listed were shown to be true. b. Interaction between a cell-bound receptor and pathogen could induce the cell to proliferate. c. The specificity of receptors was determined in the host prior to exposure to a foreign antigen. d. The binding of a receptor to an infectious agent was like the fit between a lock and a key. e. The antigen selected the appropriate receptor in a specific manner.

a. All the ideas listed were shown to be true.

Which of the following is a fungal pathogen? a. Candida albicans b. Poliovirus c. Bordetella pertussis d. Leishmania major e. Vibrio cholera

a. Candida albicans

What happens to a pathogen as it becomes attenuated? a. It has weakened virulence. b. It becomes older. c. All of the answers are correct. d. It gets smaller. e. It becomes more dangerous to the host

a. It has weakened virulence.

How are receptors encoded for innate immunity?

through the germ-line