Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
- 3rd side (hint)
|
Vaccines |
Vaccines contain antigens which stimulate the production of specific antibodies and memory cells which provide immunity against the pathogen without it causing the disease. A second exposure to the antigen will stimulate a faster and larger secondary immune response. They may contain a small amount of inactivated/ dead/ attenuated form of the pathogen or isolated antigens. They reduce the likelihood of catching a disease in individuals and in those not vaccinated as there are fewer people to spread it - herd immunity |
|
|
|
Vaccination |
Once vaccinated, The B cell with the specific antibody for the antigen will be stimulated. It will go through clonal selection (make lots more) and then clonal expansion (via mitosis) where more antibodies will be produced. Memory cells are then formed for long term possible encounters. If the person encounters the actual pathogen the memory cells will then differentiate into plasma cells. These plasma cells produces rapid production of antibodies. |
|
|
|
Herd immunity |
Herd immunity occurs when the vaccination and immunity of a significant proportion of the population provides protection for individuals who have not developed immunity as it is difficult for the pathogen to be transmitted. |
|
|
|
Antigenic variability |
Some pathogens like influenza constantly develop new strains, due to mutations in the genes which code for different antigens, resulting in antigenic variability. This makes it difficult to immunize a patient against the pathogen with just a single vaccine as the memory cells produced from the vaccine are unable to recognise the different antigens of the different strains, so the immune system has to carry out a primary response upon reinfection. Effective vaccines must be developed regularly. |
|
|
|
Active immunity |
Specific antibodies and memory cells produced by individual's own immune system in response to exposure to antigens. ■ natural - antigens enter body naturally ■ artificial - antigens introduced in vaccines |
|
|
|
Passive immunity |
Specific antibodies are introduced to the individual from an outside source - they're not produced by the immune system in response to exposure to antigens. ■ natural - antibodies are passed from mother to baby via placenta and breast milk ■ artificial - antibodies are introduced by injection |
|
|
|
HIV |
HIV infects and kills helper T- cells, which act as the host cells, eventually leading to the development of AIDS when number of helper T cells in the body reaches a critically low level and immune system fails, increasing susceptibility to other infections. This means helper T cells can't activate other immune cells to carry out the immune response |
|
|
|
HIV replication |
It doesn't have the enzymes or ribosomes to replicate on its own so it uses those of the host cell ● the virus uses the attachment proteins to bind to receptor molecules on the cell surface membrane of the host helper T cells. ● capsid is released into cell where it uncoats and released RNA into cell cytoplasm ● reverse transcriptase makes complementary DNA strand from viral RNA template, and it's inserted into host cells DNA . ● host's ribosomes use viral DNA to synthesize new proteins which assemble to form viral particles. ● viruses fill the cell until it bursts, releasing the viruses to infect other cells |
|
|
|
Symptoms of AIDS |
People with AIDS develop diseases that wouldn't cause serious infections in people with a healthy immune system. Initial symptoms are minor infections of the mucous membranes and lungs, but as AIDS progresses, there are fewer immune system cells able to fight the infections, so the infections become more serious and eventually lead to death in the late stages of AIDS - when number of immune cells is very low. |
|
|
|
Antibiotics |
Antibiotics kill bacteria by targeting bacterial enzymes and ribosomes to interrupt the metabolic reactions. Antibiotics only target bacteria and don't harm human cells as bacteria have different enzymes and ribosomes than human cells. Antibiotics can't kill viruses as they don't have their own enzymes and ribosomes, and instead use those of the host cell, which antibiotics don't harm. |
|
|
|
Antiviral drugs |
Antiviral drugs are designed to target virus specific enzymes like reverse transcriptase, that HIV uses, which human cells don't use, so they can slow down the progression of viral infections without harming human cells. |
|
|
|
Controlling HIV |
Best way is to reduce the spread. It's spread by: ▪exchanging bodily fluids ▪sexual intercourse ▪vertical transmission from mother to baby Taking antiviral drugs during pregnancy reduces chance of baby being born with HIV if mother is HIV positive. Not all babies born from HIV positive mothers are infected with HIV because HIV antibodies are passed down from the mother regardless. |
|
|
|
Ethical issues |
● vaccines are first tested on animals and the cells used to make monoclonal antibodies are taken from animals - some disagree with this usage of animals ● volunteers for vaccine testing may put themselves at risk because they think they're protected from the disease ● some don't want to take vaccines due to the risk of side affects - but this may put others at risk |
|
|
|
Monoclonal antibodies |
These are antibodies produced from a single group of genetically identical plasma cells. Antibodies are specific because their variable regions have a unique base sequence and unique tertiary structure which can only bind to a specific antigen with the complementary shape. |
|
|
|
Cancer treatment |
Different body cells have different surface antigens. Cancer cells have antigens called tumour markers that aren't found on normal body cells. ■ monoclonal antibodies can be produced to bind to tumour markers ■ anticancer drugs are attached to the monoclonal antibodies ■ when the antibodies bind to the tumour markers, they deliver the anticancer drugs to the cancer cells without harming nearby body cells So there are fewer side effects to antibody based treatments than other cancer treatments as they only target the cancer cells |
|
|
|
Pregnancy test |
Pregnancy tests detect the presence of the hormone hCG which is found in the urine of pregnant women. ● application area contains antibodies specific to hCG bound to blue beads. The test strip contains antibodies specific to hCG that are immobilized ■ the urine is applied to the application area and if hCG is present, it'll bind to the antibodies with the blue beads, forming antigen antibody complex ■ if no hCG is present, then the antibodies with the blue beads won't form any antigen antibody complexes ■ the urine carries the antibodies up the stick to the test strip ■ if hCG is present in the urine, it'll bind to the immobilized antibodies at the test strip, holding the antigen antibody complexes down and the blue beads turn the strip blue ■ if hCG isn't present in the urine, the antibodies with the blue beads won't bind to the immobilized antibodies at the test strip and will just pass through, so the strip doesn't turn blue |
|
|
|
HIV structure |
Genetic material (RNA) and proteins (reverse transcriptase enzyme - helps replication) in the core, surrounded by protein coat (capsid) and an envelope (cell membrane stolen from previous host cell) with attachment proteins to help attach to host helper T cell. |
|
|
|
ELISA test |
This can be used to test for an infection by seeing if a patient has antibodies to a specific antigen (indirect) or has antigens to a specific antibody (direct). Secondary antibodies with specific enzymes attached are used, and they react with a particular substrate to form a coloured product. So, if there's a colour change, the antibody/ antigen is present in the sample. |
In some tests, the quantity of antigen/ antibody can be found by measuring the intensity of the colour change |
|
|
Direct ELISA test |
This test is used to see if the patient has the antigens of a specific pathogen. ■ antibodies that are complementary to the specific antigens are bound to the bottom of a well plate ■ a sample of the patients blood plasma is added, and any antigens specific to the antibodies will bind to the antibodies bound to the well plate, forming antigen antibody complexes. The plate is washed out to remove any unbound antigens. ■ secondary antibodies with specific enzymes attached are added to the well plate, and they bind to the antigens of the antigen antibody complexes. ■ the well plate is washed out again to remove any unbound secondary antibodies. If the blood sample didn't contain any of the specific antigens, all the secondary antibodies will be washed away. ■ a solution is added to the well plate, containing a particular substrate which reacts with the enzymes attached to the secondary antibodies to produce a coloured product. ■ if the solution changes colour, this indicates that the secondary antibodies have formed complexes with the antigens, and as the antigens are present in the blood sample, the patient has the infection. |
|
|
|
Direct ELISA test |
This test is used to see if the patient has the antigens of a specific pathogen. ■ antibodies that are complementary to the specific antigens are bound to the bottom of a well plate ■ a sample of the patients blood plasma is added, and any antigens specific to the antibodies will bind to the antibodies bound to the well plate, forming antigen antibody complexes. The plate is washed out to remove any unbound antigens. ■ secondary antibodies with specific enzymes attached are added to the well plate, and they bind to the antigens of the antigen antibody complexes. ■ the well plate is washed out again to remove any unbound secondary antibodies. If the blood sample didn't contain any of the specific antigens, all the secondary antibodies will be washed away. ■ a solution is added to the well plate, containing a particular substrate which reacts with the enzymes attached to the secondary antibodies to produce a coloured product. ■ if the solution changes colour, this indicates that the secondary antibodies have formed complexes with the antigens, and as the antigens are present in the blood sample, the patient has the infection. |
|
|
|
Indirect ELISA test |
This test is used to see if the patient has the antibodies specific to the antigens of a specific pathogen. ■ the specific antigens are bound to the bottom of a well plate ■ a sample of the patients blood plasma is added, and any primary antibodies specific to the antigens will bind to the antigens bound to the well plate, forming antigen antibody complexes. The plate is washed out to remove any unbound antibodies. ■ secondary antibodies with specific enzymes attached are added to the well plate, and they bind to the primary antibodies of the antigen antibody complexes. ■ the well plate is washed out again to remove any unbound secondary antibodies. If the blood sample didn't contain any primary antibodies, all the secondary antibodies will be washed away. ■ a solution is added to the well plate, containing a particular substrate which reacts with the enzymes attached to the secondary antibodies to produce a coloured product. ■ if the solution changes colour, this indicates that the secondary antibodies have formed complexes with the primary antibodies, so the antigens are present in the blood sample and the patient has the infection. |
|
