7. Immunity Flashcards
Define vaccination
A vaccine is a solution containing a dead, weakened or attenuated form the of the pathogen or antigen (or mRNA instructions to make an antigen).
State what passive immunity means
Short term immunity, recieving antibodies from another source. No B memory cells are made.
Describe what active immunity means
Producing own antibodies by the humoral immune response. This leads to B and T memory cells that remain and cause longer term immunity.
Define a pandemic
A significant rise in the level of incidence of a disease globally
Define an epidemic
A significant rise in the level of incidence of a disease in a population
Define endemic
The normal level of incidence of a disease in a population.
State the 8 strategies used to control the spread of a pathogen.
Identify pathogen
Identify method of transmission
Block modes of transmission
Quarantine
Protect health workers.
Treat with appropriate medicine (e.g. antibiotics or antivirals)
Design a specific medicine
Create a vaccine
*Be careful of context of the question.
Define zoonosis
An infectious disease that is caused by a pathogen that has transferred from an animal to a human.
State 2 reasons why diseases can re-emerge
Global travel
Insufficient vaccination
Evolution and mutation of the pathogen (antigenic drift or shift)
An example of artifical active immunity is a …
vaccination
An example of natural active immunity is..
infection of a pathogen causing the creation of your own antibodies and B memory cells
An example of natural passive immunity is ..
transfer of antibodies in breastmilk or across the placenta
An example of artificial passive immunity is ..
an antivenom or injection of antibodies. Including monoclonal antibodies
An auto immune diseases is caused by …
when auto antibodies recognise self cells as foreign and attack them.
Define an allergy..
inappropriate or exaggerated reaction of the immune system to an unimportant stimulus that leads to excessive inflammation.
involves the excessive release of histamine by mast cells causing exaggerated inflammation and mucus production.
Mast cells release
histamine
Histamine causes
vasodilation and increased permeability
A secondary humoural immune response produces a …..
more rapid and higher concentration of antibody production
In an allergic reaction Ig E antibodies have formed cross links to …
allergen and two antibodies
Possible strategies to limit transmission of pathogens are
Quarantine, masks, gowns, gloves, close borders, educate, treat - vaccination, drug, RDD, remove vector
Emergent diseases can be caused by
Antigenic shift and Zoonosis
Monoclonal antibodies are …
are laboratory produced antibodies that can bind to a specific and complementary antigen on a cancer cell, usually administered by a drip.
What is Herd immunity?
Herd immunityoccurs when a large portion of a community (normally more than 90%) becomes immune to a disease, making the spread of disease from person to person unlikely.
Herd immunity reduces the number of potential hosts.
Disinfectants …
destroy pathogens on surfaces e.g. door, work top
Antiseptics …
destroy pathogens on the body
Antigenic shift is ….
Definition:
Sudden and significant mutations in the genes encoding for viral surface antigens
when the genetic material from two different viruses is accidentally combined within an infected cell creating a ‘new’ pathogen
Why do diseases re-emerge?
Evolution and mutation of the pathogen
Globalisation and travel
Larger human population
Insufficient vaccination
Immune deficiency is caused by …
malfunction or deficiency of one or more parts of the Immune System
How are monoclonal antibodies made using a mouse.
Identify antigen on cancer cell
Vaccinate mouse with antige
Extract B cells
Fuse B cells with myeloma cells, to create hybridoma cells.
Myeloma cells are actually also cancerous plasma cells.
Selection of appropriate hybridomas
Collection and purification.
Define re-emergence of a disease.
A disease that reappears after being absent in a population for a significant period of time.
Define emergence of a disease
An infectious disease that is new to the human population, or that is rapidly increasing in incidence
Describe the steps in making monoclonal antibodies using genetic engineered bacteria.
Identify antibody gene from selected hybridoma and use reverse transcriptase to get c.DNA
Cut gene and plasmid using the same endonuclease.
Stick gene into plasmid using DNA ligase which joins the sugar phosphate backbone.
Transform bacteria using heat or electrical shock
Check for successful transformation (usually using an antibiotic or GFP). Untransformed bacteria will die with the antibiotic. Successful will express the gene making the antibodies.
Collect and purify monoclonal antibodies
Define antigenic drift
Small and gradual changes in the genes encoding viral antigens
State the functions of monoclonal antibodies
Flag for phagocytosis by macrophages
Deliver toxic drug (if conjugated/loaded)
Activate natural killer cells
Activate complement proteins
Describe the first step that occurs towards having an allergic reaction
Sensitisation. This means that IgE antibodies released from the humoral immune response attach to mast cells by their non variable region.
Describe the second step towards an allergic reaction.
Degranulation. This means that after the allergen forms a cross link between two IgE antibodies attached to mast cells, histamine is excessively released from the mast cell.
