Which of the following belongs to the first line of defence against infection?
Correct answer: B. Intact skin and the mucous membranes of the body openings
- A. Production of antibodies by plasma cells
- B. Intact skin and the mucous membranes of the body openings
- C. Activation of cytotoxic T lymphocytes
- D. Formation of memory cells after an infection
Explanation
The first line is a physical and chemical barrier that stops pathogens entering at all: unbroken skin, mucus that traps microbes, cilia that sweep them out and acidic secretions. It is non specific, acting the same way against every organism, and it needs no previous exposure. Antibodies, T cells and memory cells all belong to the third line, the specific immune response.
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About Specific Defense Mechanism
Specific defense mechanisms provide targeted immunity through B lymphocytes, T lymphocytes, antibodies and memory cells that recognize particular antigens. Questions cover humoral and cell mediated responses, clonal selection, primary and secondary immune responses, vaccination and passive immunity, while distinguishing adaptive defenses from the immediate, non specific innate response.
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