Immune System Questions and Answers

Q: Lack of reaction to our own human leukocyte antigens (HLAs) is known as?

Correct answer: toleranceTolerance is the trained unresponsiveness of the immune system to the body’s own molecules. It is established chiefly in the thymus and bone marrow, where lymphocytes reacting strongly to self antigens are deleted or silenced, and maintained afterwards by regulatory T cells. When it fails, the result is autoimmunity.

Q: An insect bite may result in inflammation of that spot. It is triggered by alarm chemicals such as

Correct answer: Histamine and kininsThe swelling and redness round a bite are produced by locally released mediators. Histamine comes from mast cell granules and dilates the small vessels while making them leaky; kinins, chiefly bradykinin, do the same and also stimulate the pain fibres, which is why the spot itches and hurts. Interferons act against viruses, opsonins tag microbes for phagocytosis, and histones are nuclear proteins.

Q: Interferons are

Correct answer: Cytokine barriersInterferons are cytokines released by virus-infected cells; they make neighbouring cells resistant to infection and rouse natural killer cells. They belong to the cytokine barrier of innate immunity - chemical signals rather than physical structures or cells.

Q: Which of the following provides specific defence against viruses and bacteria by producing antibodies?

Correct answer: B cellsAntibodies are made by B cells - strictly, by the plasma cells they mature into - and each antibody fits one particular antigen, which is what makes the defence specific. Complement and inflammation are innate and non-specific; T cells are specific too, but they act on infected cells rather than by secreting antibody.

101.

Lack of reaction to our own human leukocyte antigens (HLAs) is known as?

A.autoimmunity
B.complement system
C.clonal selection
D.tolerance

Answer: D

Correct answer: tolerance

Tolerance is the trained unresponsiveness of the immune system to the body’s own molecules. It is established chiefly in the thymus and bone marrow, where lymphocytes reacting strongly to self antigens are deleted or silenced, and maintained afterwards by regulatory T cells. When it fails, the result is autoimmunity.

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102.

An insect bite may result in inflammation of that spot. It is triggered by alarm chemicals such as

A.Histamine and dopamine
B.Histamine and kinins
C.Interferon and opsonin
D.Interferons and histones

Answer: B

Correct answer: Histamine and kinins

The swelling and redness round a bite are produced by locally released mediators. Histamine comes from mast cell granules and dilates the small vessels while making them leaky; kinins, chiefly bradykinin, do the same and also stimulate the pain fibres, which is why the spot itches and hurts. Interferons act against viruses, opsonins tag microbes for phagocytosis, and histones are nuclear proteins.

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103.

Interferons are

A.Cytokine barriers
B.Physical barriers
C.Cellular barriers
D.Physiological barriers

Answer: A

Correct answer: Cytokine barriers

Interferons are cytokines released by virus-infected cells; they make neighbouring cells resistant to infection and rouse natural killer cells. They belong to the cytokine barrier of innate immunity - chemical signals rather than physical structures or cells.

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104.

Adaptive immune responses are more specific that innate immune responses.

A.True
B.False

Answer: A

Acquired (or adaptive) immune systems are more specific than the innate immune responses and can distinguish between two very similar molecules. The adaptive immune responses possess a memory i.e. an individual cannot develop the same disease twice.

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105.

Which of the following provides specific defence against viruses and bacteria by producing antibodies?

A.T cells
B.B cells
C.Complement
D.inflammation

Answer: B

Correct answer: B cells

Antibodies are made by B cells - strictly, by the plasma cells they mature into - and each antibody fits one particular antigen, which is what makes the defence specific. Complement and inflammation are innate and non-specific; T cells are specific too, but they act on infected cells rather than by secreting antibody.

Discuss in Forum

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