The immune responses Flashcards
What is phagocytosis?
This is when a white blood cell (phagocyte) engulfs, ingests then digests a microbe (pathogen). The microbe is destroyed by powerful digestive enzymes within the phagocytes.
What do phagocytes contain more of than other white blood cells?
Lysozymes. They are digestive enzymes used to break down pathogens.
Which white blood cells release antitoxins?
Lymphocytes
What do antitoxins do?
They link to the toxin and neutralise its effect - the toxin is now harmless. This happens on a large scale and reduces the effects of the infection.
What are antigens?
Every pathogen and cell in our bodies has unique molecules on its surface called antigens.
What are ‘self-antigens’?
Our cells’ antigens
What are non-self/foreign antigens?
The pathogens’ antigens.
Are antigens good?
They are only bad if they belong to a pathogen.
Describe the process of releasing antibodies
Lymphocytes detect foreign antigens and produce special Y-shaped proteins called antibodies.
The antibodies bind to the antigens on pathogens, ‘labelling’ them.
This causes them to clump together and stops them spreading further.
How do our antibodies fit into the antigens of pathogens?
Each different type of antigen causes a different type of antibody to be produced.
An antibody can only bind to the antigen that caused it to be produced.
They’re complementary.
How do different variants affect the shape of the pathogen?
They change the shape of the pathogen so you need different antibodies and you need a new vaccine.
What happens if a person becomes infected by the same pathogen again?
The white blood cells will rapidly produce the specific antibodies needed to kill it. The person is immune to that pathogen.
What are memory cells?
Once a pathogen has been in the body and destroyed, some of the white blood cells form memory cells. This means they remember how to make the same antibodies if that same pathogen ever gets into the body again. This allows the immune system to respond much faster.
Why does it take a day or two for the primary response after being infected by a pathogen for the first time?
The white blood cells are synthesising new antibodies. This is known as lag time.
