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)
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1
Q

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

A

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

2
Q

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

A
  • 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
Q

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

A

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

4
Q

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

A

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
Q

Where do T-lymphocytes mature?

A

In the thymus

6
Q

Where are all lymphocytes produced?

A

Bone marrow

7
Q

Where do B-Lymphocytes mature?

A

In the bone marrow.

8
Q

What is meant by cell mediated immunity?

A

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
Q

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

A
  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 Th cell 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
Q

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

A
  • 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
Q

what is an antigen?

A

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

12
Q

what is an antibody?

A

Protein specific to an antigen

produced by B cells/secreted by plasma cells

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