Flashcards in M26. Immune response and Vaccinations Deck (39)
What are memory cells?
cells that circulate in the blood after an immune response that speed up the response to a subsequent attack by the same pathogen.
What are lymphocytes?
white blood cells that circulate round the body in the blood and lymph. B cells mature in the bone marrow, while T cells originate in the bone marrow but mature in the thymus gland.
How does an immune response provide long term protection from the disease?
As it produces immunological memory through the release of memory cells which circulate in the blood for a number of years.
Which cells detect invading antigens?
T and B lymphocytes
Why does it sometimes take some time for the antigens to be detected by T and B lymphocytes?
As there may only be one or two of the particular lymphocytes.
What increases the chances of the correct B and T lymphocytes finding the antigen?
As cells that are attacked by the antigen display the antigens on their surface (and macrophages become antigen presenting cells)
What is the selection of the correct B and T lymphocytes known as ?
clonal selection as they must increase in numbers before they can become effective at attacking the pathogen (clonal expansion)
What is clonal expansion? (how does it occur?)
B and T lymphocytes increasing in numbers before they can become effective at attacking the pathogen (by mitosis)
Do B and T lymphocytes manufacture antibodies directly?
What 3 type of cells do T lymphocytes differentiate into?
What 2 type of cells do B lymphocytes differentiate into?
plasma cells/ effector
B memory cells
What do T helper cells do?
release cytokines (chemical messangers) that stimulate the B cells to develop and stimulate phagocytosis in phagocytes
What do T killer cells do?
they attack and kill the CELLS that have been invaded by pathogens
What do plasma cells/ effectors do
flow round in the blood, manufacturing and releasing the antibodies.
What do B memory cells do?
they remain in the body for a number of years and act as an immunological memory
Why does the immune response takes a few days ? (from lymphocyte selection to plasma cells manufacturing antibodies)
As there are so many steps:
- correct lymphocyte must be selected
- cells must divide to increase in number
- differentiate into plasma cells
- plasma cells manufacture antibodies
What is vaccination?
a deliberate exposure to antigenic material, which activates the immune system to make an immune response and provide immunity
What is a person described to have when they have been vaccinated? and what is it?
artificial active immunity, which is created by being deliberately exposed to antigenic material that has been rendered harmless, but the immune system treats it as a real disease so produces antibodies and memory cells, which provides long-term immunity.
Name the 5 different forms antigenic material can be used in a vaccine
1. whole, live, microorganisms- usually ones not as harmful as those that causes the real disease.
2. a harmless or attenuated version of the pathogenic orgnanism (eg TB or measles vaccines)
3. A dead pathogen (eg typhoid or cholera vaccines)
4. a preparation of the antigens from a pathogen (eg. hepititis B vaccine)
5. some harmless toxin called a toxoid (eg tetanus vaccine)
How can vaccines be achieved?
either by injection or orally.
What can be vaccination be used for on a large scale
to control disease by providing immunity to all those who are at risk.
What are the two main ways for large scale vaccination?
Herd vaccination or ring vaccination
What is Herd Vaccination
using a vaccine to provide immunity to all or almost all the population at risk, as once enough of the population is vaccinated, the disease stops spreading.
What percentage of the population had to be vaccinated to eradicate smallpox?
What percentage of people is it thought would have to be vaccinated against measles to eradicate it?
Name some examples of vaccination programmes there have been to immunise children against?
What is ring vaccination?
vaccinating people in the immediate vicinity of the new cases , which may mean vaccinating people in surrounding houses or even a whole village/town.
When is ring vaccination used?
when a new case of a disease is reported.
Why are pathogenic organisms constantly a future threat, even if they are already being dealt?
as new strains of the organism can form by mutations, this is most common with viruses