6.3.4 - Cell-medicated response

Question 1

Describe the process of T killer cell activation.

Answer 1

1) An antigen presenting cell digests and engulfs a pathogen and presents it on its surface via an MHC molecule.
2) T killer cell with complementary T cell receptors bind to the MHC on the antigen.
3) With the assistance of cytokines from an activated T helper cells , the T killer cell becomes activated

Question 2

What do T killer cells do once they become activated?

Answer 2

They release perforin chemicals.
These punch holes in the membrane of infected cells and cause them to burst.

Question 3

What cells do T killer cells attack?

Answer 3

Body cells which have been agenetically altered by viruses or cancer cells

Question 4

Difference between T killer cells and T helper cells.

Answer 4

T helper cells produce chemicals which stimulate the production of antibodies
T killer cells produce chemicals which destroy pathogens.

Question 5

Explain why T killer cells do not attack healthy, uninfected cells.

Answer 5

Each T cell receptor is complementary foreign antigens on the surface of pathogens. Any T cells that are complementary to self-antigen, are removed early in development. The cells of the body have antigens which the immune system recognises as ‘self’ and so does not attack them.