50. Immune response - diversity and memory. Primary and secondary response, cellular and humoral response.

Question 1

• Specificity: able to distinguish among different antigens and so it is defined by the epitopes. It’s not complete (cross reactivity)
• Adaptiveness: ability to respond to previously unseen invaders
• Discrimination between “self” and “non-self”
• memory: ability to recall previous contact with a foreign molecule and respond in a “learnt” way

Answer 1

• Specificity: able to distinguish among different antigens and so it is defined by the epitopes. It’s not complete (cross reactivity)
• Adaptiveness: ability to respond to previously unseen invaders
• Discrimination between “self” and “non-self”
• memory: ability to recall previous contact with a foreign molecule and respond in a “learnt” way

Question 2

Primary immune response

• refers to the period where the body first encounters the foreign antigen and reacts to it developing memory

Secondary immune response

• when the body encounters the antigen again, developing a larger, stronger and quicker response

Answer 2

Primary immune response

• refers to the period where the body first encounters the foreign antigen and reacts to it developing memory

Secondary immune response

• when the body encounters the antigen again, developing a larger, stronger and quicker response

Question 3

Lines of defence

1st line:

• non-specfic
• including skin, mucous membranes and body fluids 2nd line:
• Including Natural Killer cells, macrophages, complement system, interleukins, neutrophils, interferon
• Cellular response

3rd line:

• Specific, including humoral response
• T Cells and B cells activated by antigen presenting cells

Answer 3

Lines of defence

1st line:

• non-specfic
• including skin, mucous membranes and body fluids 2nd line:
• Including Natural Killer cells, macrophages, complement system, interleukins, neutrophils, interferon
• Cellular response

3rd line:

• Specific, including humoral response
• T Cells and B cells activated by antigen presenting cells

Question 4

Cellular response

• carried mainly by T lymphocytes which have many identical non-selected receptors and circulate directly through the site
• T helper cells: co-operate with B cells to enhance production of antibodies, they release substances (lymphokines) that provide activation sequels for B cells
• TDTH (delayed type hypersensitivity cells): produce inflammation by inducing migration and activation of macrophages and monocytes
• Tc (cytotoxin): upon direct contact, they release substances to kill the cells
• Ts (T-supressor): shut down the immune response

Answer 4

Cellular response

• carried mainly by T lymphocytes which have many identical non-selected receptors and circulate directly through the site
• T helper cells: co-operate with B cells to enhance production of antibodies, they release substances (lymphokines) that provide activation sequels for B cells
• TDTH (delayed type hypersensitivity cells): produce inflammation by inducing migration and activation of macrophages and monocytes
• Tc (cytotoxin): upon direct contact, they release substances to kill the cells
• Ts (T-supressor): shut down the immune response

Question 5

Humoral response

• involves the production of antibodies by B cells and clonal selection theory

Clonal selection theory:

1. antibody and lymphocytes of countless specificity exist before any contact with foreign antigens
2. lymphocytes have antigen receptor sites
3. each lymphocyte carries receptor molecules of a single specificity
4. immunocompetent lymphocytes proliferate and differentiate into clones of cells making antibodies
5. circulating “self” antigens reach the developing lymphoid system for it to recognise them and not induce an immune response later on. Lymphocytes potentially react with “self” are deleted or inactivated
   - binding of the antibodies to the foreign antigens causing neutralisation, opsonisation (make a cell more susceptible to phagocytosis) and complement system activation.

• causes the lysis of cell or enhance phagocytosis
• activation of complement system - results in polymorphonuclear cells

Inflammatory response - histamines, phagocytotic cells and fever may all play a role in local inflammations

Answer 5

Humoral response

• involves the production of antibodies by B cells and clonal selection theory

Clonal selection theory:

1. antibody and lymphocytes of countless specificity exist before any contact with foreign antigens
2. lymphocytes have antigen receptor sites
3. each lymphocyte carries receptor molecules of a single specificity
4. immunocompetent lymphocytes proliferate and differentiate into clones of cells making antibodies
5. circulating “self” antigens reach the developing lymphoid system for it to recognise them and not induce an immune response later on. Lymphocytes potentially react with “self” are deleted or inactivated
   - binding of the antibodies to the foreign antigens causing neutralisation, opsonisation (make a cell more susceptible to phagocytosis) and complement system activation.

• causes the lysis of cell or enhance phagocytosis
• activation of complement system - results in polymorphonuclear cells

Inflammatory response - histamines, phagocytotic cells and fever may all play a role in local inflammations