An antibody, also known as an immunoglobulin, is a large Y-shaped protein produced by the immune system to neutralize pathogens such as bacteria and viruses.

An antigen is a substance that triggers an immune response in the body.

An antigen-presenting cell (APC) or accessory cell is a cell that displays an antigen bound by major histocompatibility complex (MHC) proteins on its surface; this process is known as antigen presentation.

Cellular immunity, also known as cell-mediated immunity, is an immune response that does not rely on the production of antibodies.

An electron microscope is a type of microscope that uses a beam of electrons to produce a magnified image of a sample.

ELISA (enzyme-linked immunosorbent assay) is a widely used laboratory technique used to detect and quantify the presence of specific proteins, antibodies, or antigens in a sample.

Glycosylation is the reaction in which a carbohydrate (or 'glycan'), i.