specific immune response

Question 1

Specific immune response

Answer 1

Target a specific pathogen although it is slower to act than a non-specific response

Immune memory cells mean it responds very quickly to a second invasion by the same pathogen

Features two types of response to pathogens (cell-mediated response, humoral response)

Question 2

Cell-mediated response

Answer 2

Highly specialised cells

targets pathogens that have invaded cells/cells that have been changed in some way such as mutations

Question 2

Humoral response

Answer 2

Targets pathogens in body fluids using antibodies

Question 3

Cell-mediated immunity

Answer 3

Macrophage destroys a pathogen by phagocytosis, display the pathogen’s antigen on its cell surface, cell called an antigen-presenting cell

Antigen-presenting cell interacts with a specially selected T helper cell (one that has receptor that can bind to an antigen)

On binding, antigen-presenting cell releases a chemical substance called interleukin-1

Interleukin-1 stimulates the T helper cell to release another cytokine interleukin-2 which stimulates the growth and development of T killer cells, colonal selection

T killer cells bind to the antigen on the surface of infected body cells, release perforin(forms pores in the cell membrane–> water and ions to enter); lysis of the host cell

T memory cells are produced, ready to initiate a response if they ever recognise the specific antigen again

Question 3

Lymphocytes and the immune response

Answer 3

Type of white blood cell (leukocyte) found in the blood and in the lymph nodes

Recognise antigen molecules on the surface of the pathogens

Large variety of types of lymphocytes which means collectively, can identify millions of different pathogens

B lymphocytes (bone marrow), T lymphocytes (thymus gland)

Question 4

Humoral immunity

Answer 4

Macrophage destroys a pathogen by phagocytosis, display antigen on the cell surface, cell called antigen-presenting cell

antigen-presenting cell interacts with specific T helper cell, release interleuklin-1(cytokine – chemical involved in cell signalling)

Interleukln-1 stimulate the t helper cell to release interleukin-2,stimulates the differentiation of b effector cells into plasma cells

Plasma cells divide by mitosis, clone of each other, (colonal expansion)plasma cells produce large amounts of antibody, antibody destroy the pathogen by agglutination/neutralisation

B memory cells are produced, ready to initiate a response if they ever come into contact with the specific antigen again