Cell -mediated Response

Question 1

What lymphocytes and cells are involved in this response?

Answer 1

T lymphocytes and T cells

Question 2

What type of response is this?

Answer 2

Specific

Question 3

Where are lymphocytes made but where are T cells matured?

Answer 3

Made in the bone marrow but T cells mature in the thymus

Question 4

What is an APC?

Answer 4

Any cell that presents a non-self antigen on its surface

Question 5

Why is it called a cell-mediated response?

Answer 5

T cells only respond to antigens which are presented on cells (APC) and not antigens detached from cells and within body fluids like the blood

Question 6

What is the cell mediated response?

Answer 6

1) once a pathogen has been engulfed and digested by a phagocyte, the antigens are positioned on the cells surface of the phagocyte- forming an APC
2) helper T cells have complementary receptors on their surface cells which can attach to the antigens on APC
3) B cells with complementary antibodies on their cell surface bind to antigens and are activated (clonal selection)
4) once the T helper cells have attached, this activates (clonal selection) the helper T cells to divide by mitosis (clonal expansion) to produce more lymphocytes specific to the antigen and make large number of clones.
5) cloned helper T cells differentiate into different cells- some remain as helper T cells and activate B lymphocytes, some become cytotoxic T cells (killer T cells)

Question 7

Cell mediated response

Answer 7

Phagocyte engulfs and digests pathogen- forming an APC.
T helper cell binds to APC, activating the T helper cell.
T helper cell divides by mitosis, forming a clone of cells.
Cytotoxic T cell binds antigens on infected cell
T helper cell binds to cytotoxic T cell- activating cytotoxic T cell.
Activated cytotoxic T cell divides by mitosis, destroys infected cells or turns into a memory cell.