(no subject)

leukocyte: the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders.
macrophage: a type of white blood cell that engulfs and digests cellular debris, foreign substances, microbes, and cancer cells in a process called phagocytosis
phagocytosis: the foreign particle is coated with ligands. The macrophage is initially flat, with receptors. As the ligands bind to the surface receptors of the macrophage, the macrophage clusters around the particle and envelops it.

lymphocyte: a type of leukocyte that includes B lymphocyte and T lymphocyte. Their job is recognize specific “non-self” antigens, during a process known as antigen presentation.
B lymphocyte
T lymphocyte

antigen presentation: Immune cells can't see what goes on inside other cells. Diseases may be developing inside those cells. So the cells break up some of the stuff inside and move it outside the cell. Cytotoxic T cells visit the outside of the cell and inspect it for foreign/bad stuff.

The MHC molecules live on the outside of the cell. It binds to the protein fragment that determines whether it's an antigen, aka the antigenic determinant, aka the epitope.

The T-cell receptor is part of the cytotoxic T cell and is coded to recognize a specific antigen.

Immunoglobulin G is a Y-shaped cell that binds to antigen at the tips of the Y branches.


humoral immune system
cellular immune system
hapten

Fc
Fab
immunoglobulin fold
IgD, IgE, IgM, IgA