Question

Mark the following statements as true or false.
I. In acquired immunity, pathogen-specific receptors are "acquired" during the lifetime of the organism.
II. Antigen is any portion of a pathogen that the body recognizes as foreign or harmful to the body resulting in imuune response.
III. Acquired immunity is first line of defence.

• A. I - T, II - T, III - T
• B. I - T, II - F, III - T
• C. I - T, II - T, III - F
• D. I - F, II - F, III - T

Answer 1

The correct option is C I - T, II - T, III - F

The immunity obtained during a lifetime of an individual is called acquired immunity, also called adaptive immunity. This type of immunity is pathogen-specific.

Antigen is any portion of a pathogen that the body recognizes as foreign or harmful to the body, which can result in an immune response.

When the body encounters the pathogen or antigen when exposed to infectious diseases or when immunized, the body fights against the pathogens and generate immunity for future attacks. It is specific and mediated by antibodies or lymphocytes which make the antigen harmless. As this immunity is developed against a specific antigen, thus pathogen-specific receptors are acquired.

Immunity present in an individual since birth is called innate immunity. This type of immunity has different line of defence:

• first line of defence : physical barriers and physiological barriers
• second line of defence : cellular and cytokine barrier

When innate immunity barriers are not enough and pathogen is able breach innate defences, a more targeted response is needed i.e., adaptive immunity. Acquired or adaptive immunity includes third line of defence having two componets :

• cell mediated immunity
• humoral immunity