Introduction to pathogens, allergens and antigens Flashcards
What are self proteins called?
Major Histocompatibility Complex I (MHC I).
What are antigens ?
Any set of molecules that activate the immune system are called antigens.
What are the types of antigens ?
Self-antigens (self markers)
Non-self antigens
Allergens
What are non self antigens ?
molecules that are not found on self cells.
What are self antigens ?
located on the surface of cells, they mark the cells of an organism as ‘self’ so that the immune system doesn’t attack them. In humans, the most important self-antigens take the form of major histocompatibility complex (MHC) proteins, which can be divided into two different classes:
MHCI
MHCII
What are MHCI proteins ?
expressed on all nucleated cells in the body. Therefore, virtually all cells in the human body except for those without a nucleus (e.g. red blood cells) express MHC I proteins.
What are MHCII proteins ?
found on specialized cells of the immune system.
Malfunctions involving self antigens/self-markers
self cells that set off the immune system.
What are allergens ?
molecules found on non dangerous particles that set off the immune system.
What is a disease?
Any change that impairs the function of an individual in some way.
What is an infectious disease?
A disease caused by a pathogen.
What is a pathogen ?
an agent able to cause disease in a host.
What is an infection ?
When the pathogen is present in/on the host.
What does sterile mean ?
Free of pathogens
Non cellular agents - prions
There are two forms of prions ( PrP - sen which is normal and PrP - Sc which causes disease. They are proteins that can be infectious through consumption. They can reproduce on their own. Both proteins have exactly the same primary structure but have a different tertiary structure. Prions cannot be destroyed easily.
