A Molecule Recognized as Foreign by Cells of the Immune

Question

A molecule recognized as foreign by cells of the immune system is a(n) _______.
A) antigen
B) antibody
C) pathogen
D) cytokine

Accepted Answer

An antigen is a molecule that is recognized as foreign by cells of the immune system, leading to an immune response. Antibodies are proteins that are produced by the immune system in response to an antigen to help defend against it. Pathogens are disease-causing microorganisms, which can contain antigens that trigger an immune response. Cytokines are proteins produced by immune cells that play a role in regulating immune responses.