Topic 11 Immunity2. Flashcards
What is passive immunity?
Passive immunity is a type of acquired immunity that occurs when an individual receives antibodies from an external source rather than producing them through their own immune response. This form of immunity provides immediate protection against specific pathogens but does not provide long-lasting immunity because the immune system does not produce memory cells.
What is active immunity?
Active immunity is a type of immunity that develops when an individual’s immune system is stimulated to produce antibodies in response to exposure to a pathogen or through vaccination. This type of immunity is characterized by the body’s active engagement in recognizing and responding to foreign antigens.
Memory cells are produced in active immunity.
There are two types of active and passive immunity. Name them.
Active immunity:
- Natural active immunity.
- Artificial active immunity otherwise known as Vaccination.
Passive Immunity:
- Natural passive immunity.
- Artificial passive immunity
What is the difference between artificial and natural active immunity?
Artificial active immunity is immunity gained by putting the antigens of a live or attenuated pathogen into the body, either by injection or by mouth (polio and cholera).
Natural active immunity is gained by being infected by a pathogen.
This involves exposure to the antigens of the pathogen.
What is natural passive immunity?
Natural passive immunity occurs when antibodies are transferred from one individual to another through natural processes (e.g. mother to child).
This involves putting antibodies directly into the body, Antibodies bind to antigens leading to the direct destruction of pathogens or marking of pathogens for destruction by phagocytes.
Give two example of natural passive immunity.
- The most common example is the transfer of maternal antibodies to a fetus during pregnancy through the placenta. This provides the newborn with immediate protection against certain infections for several months after birth.
- Additionally, breastfeeding allows infants to receive antibodies present in breast milk, particularly colostrum which contains a type of antibody known as IgA, which further supports their immune system during early development.
What is artificial passive immunity?
Artificial passive immunity involves the administration of pre-formed antibodies to an individual, typically through medical interventions.
Give an example of artificial passive immunity.
This can occur via injections of antibody-containing serum derived from another person or animal. This form of immunity is often used in emergency situations, such as after exposure to rabies or snake venom (antitoxin), where immediate protection is necessary.
- What is a vaccination?
- What are the different contents of a vaccine?
- How are vaccines administered?
A vaccine is a preparation containing antigens which is used to stimulate an immune response artificially.
It may contain a whole live microorganism, a dead one, a harmless version (known as an attenuated organism), a harmless version of a toxin (known as a toxoid) or a preparation of surface antigens,
Vaccines are either given by injection into a vein or muscle, or taken orally (by mouth) and some are produced using techniques of genetic engineering.
What is herd immunity?
Vaccinating a large enough percentage of the population provides protection for the entire population including those not immunised because there are very few places for the pathogen to breed - this is known as herd immunity.
What are the positive benefits of herd immunity?
- This significantly reduces the likeliness of disease transmission from one person to another.
- Herd immunity protects those who cannot be vaccinated due to medical reasons or age restrictions by lowering their risk of exposure.
What happens during an immune response in regards to:
1. The transformation of B cells during an immune response.
2. The purpose of antibodies.
3. The specificity of antibodies.
During an immune response, B cells become plasma cells that secrete antibodies in response to the presence of a non-self antigen.
Antibodies bind to pathogens and kill them or mark them for destruction by phagocytes.
Antibodies have high degrees of specificity. This specificity of antibodies makes them very desirable for use in diagnosis and treatment of disease.
What is a hybridoma cell?
A cell formed by the* fusion of a plasma cell and a cancer cell*. It can both secrete antibodies and divide to form other cells like itself.
What is a monoclonal antibody (Mab)?
Monoclonal antibodies (Mabs) are antibodies that are all identical to each other. Mabs are produced by fusing a plasma cell with a cancer cell to produce a hybridoma, which divides repeatedly to form many geneticall identical cells that all produce the same antibody.
Mabs are used in diagnosis, for example in locating blood clots in veins, and in the treatment of diseases, such as breast cancer
Why do hybridoma cells make use of plasma cells and cancer cells instead of other cells?
Hybridoma technology combines the properties of plasma cells, which are responsible for producing antibodies, and cancer cells, which can divide indefinitely. Hence, hybridoma cells divide by mitosis and secrete antibodies.
