adaptive immune system

Question 1

Humoral immunity

Answer 1

1. Clonal selection
   A naive B cell is activated by binding to an antigen. Naive t helper cells are also activated through APCs.
2. Clonal expansion
   activated T helper cells release cytokines to activated B cells, which tell them to proliferate. This clones the B cells.
3. Differentiation
   The B cells are also told to differentiate into either plasma cells or B memory cells by the cytokines.

Question 2

B plasma cells

Answer 2

Produce and secrete antibodies into the bloodstream

Question 3

B memory cells

Answer 3

Provide long lasting immunity. Continue to release low amounts of antibodies and can rapidly divide and give rise to plasma cells if secondary exposure to the antigen occurs.

Question 4

Antibodies

Answer 4

quaternary structured proteins produced by plasma cells - target extracellular pathogens

Question 5

How do antibodies interact with pathogens?

Answer 5

-Neutralisation
-Agglutination
-Opsonisation
-Activation of complement proteins

Question 6

Neutralisation

Answer 6

Antibodies can block the sites of pathogens that are used to attack host cells (e.g blocking the virus entry into cells) and can block the active sites of toxins

Question 7

Agglutination

Answer 7

Forms antigen-antibody complexes, immobilising pathogens for easier phagocytosis

Question 8

Opsonisation

Answer 8

Bind directly to the pathogen to make it easier to recognise and phagocytose

Question 9

Activation of complement proteins

Answer 9

form membrane attack complexes - disrupting the cells membrane, leading to cell death

Question 10

Cell mediated immune response

Answer 10

1. Clonal selection
   A t helper cell is selected through apc as well as a naive t cell through apc
2. Clonal expansion + differentiation
   The t helper cell releases cytokines to activate the naive t cell, as well as tell it to differentiate into either t memory cells or cytotoxic t cells
   3 Cytotoxic T cells
   the Tc leave the lymph nodes and move to the site of infection, where they secrete chemicals to induce apoptosis in the cell.