Question

Humoral immunity is mediated by
A) Cytotoxic T-cell
B) Plasma cell
C) Eosinophil
D) Neutrophil

Answer 1

Immunity is defined as the ability of the biological system to recognize and differentiate between self and non-self components also called foreign, and also to act on these non-self components to remove them out of the system.

Complete answer:
The immune system comprises two components- innate immunity and adaptive immunity. Innate immunity is also known as the native immunity as it provides the first line of defense against pathogens. It is not a specific response like the humoral immunity but it is a faster response in comparison to humoral immunity.

Innate immunity is mediated by leukocytes such as eosinophils, basophils, neutrophils, macrophages; macrophages and dendritic cells. Humoral immunity is highly specific against a particular pathogen, it not only functions in the elimination of the pathogen but also helps to develop immunological memory so that if the person is affected by the same disease twice the immune response will be much faster and greater than the first one.

Humoral immunity is mediated by antigen specific lymphocytes, T lymphocyte and B lymphocyte. T lymphocytes are of two types, Th cells that help in antigen presentation of the pathogen to the B cell and Tc cells that are known as cytotoxic T cells as they can destroy pathogens by directly interacting with them. B cells on the other hand produce antibodies specific for the given antigen and help in clearance of the pathogen.

Hence the correct answers are option (A) Cytotoxic T-cell.

Note: Both the innate and the humoral immunity is important for defense against the foreign pathogen. Improper functioning of either leads to immunosuppression and thereby development of various harmful diseases.