3.2.4.3 - Cell Mediated Immunity Flashcards Preview

SHHS - Science - NEW AQA A-Level Biology (Year 1) > 3.2.4.3 - Cell Mediated Immunity > Flashcards

Flashcards in 3.2.4.3 - Cell Mediated Immunity Deck (12):
1

Which type of immunity are T-lymphocytes mainly involved in?

Cell Mediated Immunity (they are just used to stimulate B-cells in humoural immunity)

2

Where can non-self antigens be found that T-lymphocytes may bind to?

  • The surface of an antigen presenting cell (phagocyte)
  • Body cells invaded by a virus may present viral antigens.
  • Transplanted cells from organ donors.
  • Cancer cells
  • Toxins produced by pathogens.

3

Can T-lymphocytes bind to non-self antigens floating around freely in the blood?

No - they can only bind to foreign antigens that have been presented on an antigen presenting cell e.g. phagocyte.

4

How do cytotoxic T lymphocytes (Tc) protect against disease?

They kill cells infected by pathogens or cancerous cells.

They produce a protein called perforin.

Perforin creates holes in target cell membranes, which kills the cell.

5

Where do T-lymphocytes mature?

In the thymus

6

Where are all lymphocytes produced?

Bone marrow

7

Where do B-Lymphocytes mature?

In the bone marrow.

8

What is meant by cell mediated immunity?

An immune response that does not involve the production of antibodies.

Results in the production of cytotoxic T cells that can protect against pathogens.

9

Describe the process of cell mediated immunity (immunity that does not result in the production of antibodies).

  1. Phagocytosis of foreign material by phagocyte.
  2. Foreign antigens from material are presented on phagocyte.
  3. Specific T-helper lymphocyte (Th) binds to foreign antigen (clonal selection)
  4. Attachment causes Tcell to undergo mitosis (clonal expansion).
  5. Cloned T cells can:
  • become memory cells for rapid future response.to same pathogen.
  • stimulate phagocytes to engulf via phagocytosis.
  • stimulate B cells to divide and release antibodies (humoural response)
  • activate cytotoxic T cells (Tc) cells to kill.

10

What can the cloned T-lymphocytes do after clonal expansion has taken place in the cell mediated response?

  • become memory cells for rapid future response.to same pathogen.
  • stimulate phagocytes to engulf via phagocytosis.
  • stimulate B cells to divide and release antibodies (humoural response)
  • activate cytotoxic T cells (Tc) cells to kill.

11

what is an antigen?

foreign protein that can stimulate an immune response/production of antibodies

12

what is an antibody?

Protein specific to an antigen

produced by B cells/secreted by plasma cells