antigen presenting cells, and cell mediated response.

Question 1

Explain why T-cells dont bind to antigens on a pathogen.

Answer 1

Because their receptors are only complementary to processed antigens that are showed on the surface of antigen presenting cells.

Question 2

What are the 3 types of antigen presenting cells, and explain each one of them.

Answer 2

1. B-cell ( you know the whole process).
2. some Phagocytes: when phagocytes carry out phagocytosis, some of them process the antigens and present them on their surface , so that helper T-cells can identify them.
3. our own body cells: When viruses enter our body cells , the virus begins to replicate inside the cell.
   -during this replication, antigens form, which the cell then processes and present on its surface.

Question 3

what are the two types of T-cells.

Answer 3

Helper T-cells, and cytotoxic T-cells.

Question 4

Explain what stimulates a T-cell to clone itself.

Answer 4

A naive helper T-cell bins to a complementary antigen ( usually on a phagocyte).
The binding then stimlates the helper T-cell to clone.

Question 5

What are the 3 main roles of cloned helper T-cells?

Answer 5

1. Can help stimulate B-cell ( seen process).
2. Can release chemicals which attract a phagocyte towards the pathogen.
3. can stimulate a cytotoxic T-cell (Helper T-cell).

Question 6

Explain the process of a cytotoxic T-cell.

Answer 6

Cytotoxic T-cells have receptors complementary to the modified antigen present on the surface of an infected body cell.
They cytotoxic T-cell, then binds and secretes a protein called PERFORIN.
Perforin causes wholes to form in an infected cells cell membrane membrane.
-This makes it easeir for ions to pass out of the cell, in an uncontrolled way, which will eventually lead to the infected cells death.