Lecture 2: revision of antigen and antibody

Question 1

The key steps of the innate immune response are:

Answer 1

1.Recognition
* 2.Phagocytosis
* 3.Cytokinerelease
* 4.Inflammation

Question 2

When does adaptive immune system start

Answer 2

The adaptive immune response begins once digestion of the pathogen in the phagocytic cells in the innate system has taken place

Question 3

Major histocompatibility complex (MHC)
made of?
Purpose?

Answer 3

The MHC is made of up molecules that link the innate and adaptive systems by “serving up” foreign molecules to T lymphocytes.

Question 4

Antigen presentation to T cells

Answer 4

After digestion of the pathogen in the phagocytic cells, antigen presentation to the T cells takes place

• Phagocytes ingest, process and displays antigen on their surface. Once a phagocyte has antigen on its surface, it’s called an antigen presenting cell (APC)
• The APC shows or “presents” pathogen particles (antigen) to the T cells
• The T cells use their receptors (TCR) and MHC to “look” at the pathogen particle
  to see if they recognize this specific antigen
• T cells can directly kill the pathogen-infected phagocytic cells by producing chemicals toxic to the pathogen. Once the phagocytic cell is displaying the antigen, its called an antigen presenting cell (APC), because it “presents” the antigen to the T cell

Question 5

Antigen presentation and antibody production

Answer 5

T cells present the antigen to B cells

• B cells use their receptors (BCR) and MHC to “look” at the antigen. If they recognize it, they can very quickly find in their memory the specific antibody to produce
• If they don’t recognize it, they can make a new antibody after about 72 hours