11.1 -antibody production and vaccination Flashcards
Unique molecules on the surface of a cell + examples
- The surface of an organism’s cells is coated with specific molecules
examples:
- polysaccharides in bacterial cell walls
- glycoproteins in eukaryote plasma membrane
- capsid of bacterium (protein coat)
- These specific molecules act as host binding sites for pathogens
- The body recognizes its own surface molecules, and therefore any other molecules are seen as foreign and elicit a specific immune response, (antibody production)
antigens and antibodies of red blood cells + explain ab and o
- Antibodies (immunoglobins in blood plasma) are specific to antigens
- The immune system recognizes foreign antigens and produces antibodies in response - wrong blood type causes blood clot.
- AB has no antibodies and is universal recipient
- O has no antigens and is universal donor
active immunity
Active immunity is the exposure to a pathogen which elicits an immune response and cause antibody production.
natural: exposure to chicken pox
foreign: mmr vaccine
passive immunity
Passive immunity is getting the antibodies from another organism
natural: a mothers placenta
foreign: rabies shot
B-lymphocytes are activated by t-lymphocytes in mammals
explain the process of 3rd line of defense
- Macrophages engulf pathogens and present their antigens on their surface
- helper t cells bind to the antigens and become activated
- B cells have receptors that bind to the antigens of the pathogen. However, they need the t-cells proteins to become fully activated
- Plasma proteins are specialized in producing antibodies that target the antigens which binded to the b-cells receptors. Plasma proteins can produce thousands of antibodies per second.
- Helper t-cells can produce memory cells that last much longer than b memory cells. If the pathogen is introduced again, immune response will be much faster. An organism is said to be immune if they have little to no symptoms.
Function of antibodies
Neutralization - binding stops toxins / viruses from invading cells, and bacteria from efficiently functioning and therefore invading the cell
Opsonization - binding marks the pathogen making it easier to identify by other immune cells. - easier for macrophages to engulf
agglutination - antibodies bind to each other causing the pathogen to clump
Complement activation - antibodies invite other components to bind to the pathogen and attack it - bacterial membrane attacked causing it to lyse
Challenge: first line of immune response fails. Pathogen has entered blood.
what is the response?
- Macrophage ingests the pathogen
- Macrophage presents antigen on its cell surface (epitope- surface protein molecules)
- Complementary helper t cells are activated
- helper t-cells stimulate b-cells
- b-cells divide into memory and plasma cells
- plasma cells produce antibodies
- memory cells serve as future immunity.
Histamines cause allergic symptoms
- Histamine is small organic molecule produced by two different types of leukocytes: mast cells and basophil
- mast cells are found in connective tissue. an infection stimulates the production of histamines and sends them to the infected area
- Basophil circulates and releases histamine into the blood plasma, allowing it to affect secondary sites.
- In the immune system, histamine increases the permeability of capillaries to leukocytes and proteins (antibodies)
- Histamine allows immune cells to reach sites of the infection quickly
- The release of fluid from capillaries into surrounding tissue causes:
- inflammation
- itching/irritation
- sneezing
- watery eyes
Allergy: the hypersensitivity of the immune system to something that doesn’t harm most people.
antihistamine; a drug that opposites the activity of histamine receptors
Antigens and vaccines
Vaccines contain antigens in various forms that don’t harm healthy people.
- attenuated or inactive viruses
- weakened toxins from bacterial pathogens
- subunit: antigens or only part of the pathogens that contain the antigen
- vaccines can be taken orally or through injections
- The vaccine elicits a primary immune response and the production of memory cells
- When infected with the actual pathogen, memory cells trigger a secondary immune response which is quicker
- a person is said to be immune when they experience little to no symptoms
- we require booster shots because memory cells don’t last a lifetime
Small pox
smallpox (caused by the virus variola) :
- small pox is the first infectious dieasese to be eradicated through vaccination
- this was due to a global vaccination program. The last natural case was in Somalia in 1977, and WHO declared the disease dead in 1980.
However, other diseases can not be eradicated as easily.
- Measles is transmissible before symptoms appear.
- yellow fever can be transmitted to monkeys
- malaria vaccine doesn’t guarantee lifetime immunity, people can contract it several times
Edward Jenner - small pox
- Edward Jenner infected an 8-year old boy with cowpox
- cowpox is a mild viral infection that affects cows, but is very similar to smallpox.
- he took fluid from the pocks of an infected milkmaid, and injected it into the boy
- he then tried to give the boy smallpox - and discovered he was immune.
- Jenner then did the same experiment on himself and a small group of individuals
ethical concerns by the scientific community:
- no prior research had been done before human testing to determine the effectiveness and possible side effects
- did not receive informed consent from the 8 yr old boy
zoonosis
zoonosis: the transmission of diseases from vertebrate animals to humans
many viruses are specific-specific, and can only be transmitted to humans (polio, measles, syphilis)
some viruses can be transmitted between animals and humans (flu, salmonella, ebola)
Primary immune response - difference from monoclonal antibodies
primary immune response is polyclonal - B-cells respond to multiple epitopes
steps in the production of monoclonal antiobodies
- an animal is injected with the antigen, causing a primary immune response which results in the production of specific plasma cell
- the plasma cell is extracted from the animals spleen
- the plasma cell is fused with tumour cells (capable of unlimited division) to form hyberdoma cells
- the hyberdoma cells are screened to see which produce functioning antibodies
- the chosen hyberdonas are allowed to divide, creating copies of itself.
- The hyberdoma is then used to synthesize large quantities of monoclonal antibodies used in diagnostic tests and treatments.
monoclonal antibodies in pregnancy test
monoclonal antibodies can be used to test for pregnancy via the presence of human chorionic gonadotrophin in urine.
- pregnant women with a developing fetus produce a hormone called HCG, which is present in their urine
- a process called ELISA (enzyme-linked immunosorbent assay) is used to identify a substance via colour change.
- the free monoclonal antibodies specifc to HCG are conjugated to enzymes which cause the change in colour
