U4 AOS 1 (pathogens overview and definitions) Flashcards
Pathogen
a substance that causes a disease.
Antigen
any molecule that may trigger an immune response.
Non-self antigen
a molecule from outside the body that is recognised by the immune system and initiates an immune response.
MHC
Major histocompatibility complex
Self- antigen
marks cells as self, displayed on the surface of a cell.
MHC class 1 marker
expressed on body cells with a nucleus.
MHC class 2 marker
found on specialised cells of the immune system.
Allergen
non-pathogenic antigen that triggers a reaction.
Allergic reaction
overreaction of the immune system to a non-pathogenic antigen.
Cellular pathogen
a pathogen that has a cellular structure and exhibits the processes of a living organism, eg. bacteria, fungi, protozoa, parasites.
Non-cellular pathogen
a pathogen that neither has a cellular structure nor exhibits the processes of a living organism, eg. viruses, prions
Lysis
the disintegration or rupturing of a cell.
Leukocyte
cells responsible for protecting the body, also known as white blood cells.
Antibodies
a y-shaped protein on the surface of B cells that is released into the blood to protect against pathogens, by binding to the specific antigen.
