SFBH S5 Flashcards
Identify components of the third line of defence
antibodies, T cells, B cells,
Give a description of Antibodies.
• Immunoglobins
• Proteins found in blood plasma and other body fluids
• Produced in the lymph nodes by B cells in response to specific antigen
• Can combine with and help neutralise an antigen
• Highly specific for antigen that stimulated their synthesis and release
• Antigen-antibody response
Activates production of proteins that result in bacteria being ingested and destroyed histamine released inflammation
Give a description of T cells
- Lymphocytes
- Form in bone marrow/thymus gland
- Remain inactive in blood and lymph until they meet antigen
- Cell mediated immunity: Antigen binds to T cell activating it to multiply destroy
- Some memory T-cells remain in body as memory cells so know how to fight off antigen next time introduced
- Do not produce antibodies
Give a description of B Cells
• Mature and develop in bone marrow of humans
• Control the humoral blood response B cells in blood and lymph activated by antigens
• Produced in response to helper T-activation or by the presence of antigens
• Activated B cells clone themselves and then differentiate…
Into plasma cells that send antibodies into the blood
OR into memory cells
(Process occurs in lymph nodes)
Describe the immune response in the human body in terms of the interaction between B and T lymphocytes.
• T cells help and influence B cells
• B and T lymphocytes interact as both attacking same antigen
• Helper T cells stimulate B and T cells to clone
• When antigen enters body
o Processed by macrophage places fragments of antigen on external membrane
o Fragments recognised by helper T cells and B cells
o Signal to other cells to initiate immune response
Detail Mechanism 1 that allows interaction between B and T lymphocytes
o T cell produces soluble factor after interaction with antigen
o B cell reacts with soluble factor and specific antigen becomes functional antibody-producing cell
Detail Mechanism 2 that allows interaction between B and T lymphocytes
o Contact between T and B cell because of interaction with antigen
o Contact allows T cell to signal the B cell to become functional antibody-producing cell
• Helper T cells T lymphocytes that help B lymphocytes
• Work together - T cell will recognise antigen and attack with B cell
Name the range of T lymphocytes
Killer T cells, Helper T cells, Suppressor T Cells, Memory T Cells
Whats the role of the killer T cells?
• Secrete substances
Directly destroys antigens
Enhance activity of macrophages
Inhibit replication of viruses
• Destroy any abnormal cells e.g. cancer cells
• Produce interferon protects cells living around infected cell from viral invasion
Whats the role of the Helper T cells?
• Secrete chemicals called interleukins
Help B cells produce antibodies
Help formation of cytotoxic T cells
Enhance inflammatory response
Whats the role of the suppressor T cells?
• Turn off immune response after infection controlled
Reduce release of antibodies from plasma cells
Reduce release of chemicals from cytoxic cells
Whats the role of the memory T cells?
- Recognise original invading antigen invasion dealt with quickly
- Stimulate helper T cells quickly producing large amount of antibodies
- Remain in lymph nodes or blood circulation allow long-term immunity
How do vaccination help prevent infection?
- Vaccination: injecting or ingesting antigens from living, dead, weakened or non-virulent strains of micro-organisms
- Stimulate a person’s immune system to develop resistance
- Exposure to same antigen antibody-antigen response antigen destroyed
- Some offer life-long immunity or short term
- Booster injections may be given at various intervals
What is Active immunization?
o Injection of an antigen
o Stimulates production of antibodies and T and B memory cells specific to that antigen
o Protect against measles, polio and diphtheria
What is passive immunisation?
o Injection of antibodies produced by other organism in response to infection
o Short term protection
o Risk: stimulating aggressive response
o Helpful for immediate protection: people have no immunity to disease they have
The vaccination program for small pox was?
Effective
• Virus
• Airborne or spread by direct contact
• 1796: Edward Jenner developed vaccine not effective
No one realised potential
• 1840’s: vaccine became free not widely used until became compulsory
• 1967: WHO developed worldwide immunisation program extremely successful
• 1979: WHO vaccination eradicated disease
• Only remaining samples of virus in laboratories
The vaccination program for Diphtheria was?
Ineffective,
• Bacterial infection
• Transmission physical or respiratory contact
• Vaccination DTP (prevents against Diphtheria, Tetanus and Pertussis (whooping cough)
• 1923: vaccine released
• 1940s-50s: decrease in occurrence
• 1974: WHO’s EPI program aim to immunise all children against disease (diphtheria, polio) by 1990
• 2002: 5000 death 4000 under 5
• 2005: Vaccination rate 95% across 183 countries
The vaccination program for Polio was?
Effective,
• Virus
• Transmission inhaling infected droplets or direct contact
• 1955: first vaccine developed effective to some extent years following – 200 people developed disease and 11 died
• 1960’s: safer vaccine developed decreased spread and occurrence by 60-70% (very effective)
• 1974: WHO’s EPI program became scarce in industrialised nations
• 1988: World Health Assembly – Global Polio Eradication Initiative widespread vaccination of children
Why do we suppress the immune response when doing organ transplants?
- Transplant organs stimulates immune response tissue proteins of one person not the same as another (except for twins or closely inbred strains)
- Before transplant donor and recipient very closely matched to have similar major histocompatibility complexes (MHC’s) – hundreds so hard to match
- Body identifies as foreign
- T cells main cell responsible for rejection of transplanted organs
- Patients given powerful immunosuppressive drugs suppress immune response in order to help transplanted organ live and become apart of body
- Side effects: Diabetes, renal impairment, susceptibility to infection
What did Macfarlane Burnet do?
Contribution to understanding of immunological responses
- One of the founders of immunology
- Isolated strains of viruses to develop vaccines
- Investigated how the immune response functions
