Infection + Response Flashcards
Monoclonal antibodies (mAbs) are usually made using mouse lymphocytes.
Candida albicans infection produces serious symptoms in patients with a poor immune system.
Recently scientists have produced mAbs to Candida albicans using human lymphocytes produced naturally after an infection.
Candida albicans lives in the throat of infected patients.
A sample is taken from the throat of a patient with a suspected Candida albicans
infection.
The sample is transferred onto a microscope slide.
Describe how the mAbs and a fluorescent dye could be used to see any Candida albicans pathogens on the slide.
[3 marks]
-bind fluorescent dye to mAbs
-put (bound) fluorescent mAbs on the slide (and rinse off)
-mAbs will bind to Candida albicans / pathogens and show up under the microscope
In a laboratory the human lymphocyte mAbs were injected into animals infected with Candida albicans.
The mAbs caused increased phagocytosis of the Candida albicans pathogens. Doctors intend to start a trial to give the mAbs to patients severely ill
with Candida albicans.
Explain how increased phagocytosis of the Candida albicans pathogen will help
the patient.
[2 marks]
-more Candida albicans / pathogens will be engulfed / killed by phagocytes / white blood cells
-therefore less damage to cells / tissues / organs
It has been shown that this mAbs treatment is effective in the laboratory using both:
* infected tissue culture cells
* infected live animals.
The mAbs treatment for Candida albicans is now ready for clinical trials on people.
Describe how the clinical trials should be carried out.
[6 marks]
- given first to healthy volunteers
-at(very)low dose
-to test it is safe or to test for toxicity or to check for any side effects
-then to some patients (with the disease) or people with the disease
- to test for the correct/optimum dose
-to check for any side effects
-to test for efficacy or to test if it works -in a double blind trial
-where neither patients nor doctors know who has the mAbs and who has a placebo (or alternative treatment)
-reference to large trial or long duration or control variables
Suggest one reason why these new mAbs have been more successful in treating
diseases in humans than mAbs made using mice.
[1 mark]
-the body will not reject the
mAbs
or is less likely to reject the mAbs
Before the clinical trials, drugs are tested in the laboratory. The laboratory trials are not trials on people.
What is the drug tested on in these laboratory trials?
[2 marks]
-cells
-tissues
-live animals
Drugs must be trialled before the drugs can be used on patients.
Give three reasons why.
[ 3 marks ]
-to test for toxicity/check not harmful
-test for right dosage
-interaction with other drugs
-efficacy/check they work well
Explain how vaccination makes a person immune to a disease.
[4 marks]
-a vaccination is a dead/inactive/weak form of pathogen / bacterium / virus / microorganism introduced
-when it is injected into a person, it (stimulates) white blood cells
-to produce antibodies specific to the pathogen
-antibodies made at a faster rate on re-infection / idea of memory cells
The ‘nicotine vaccine’ is made by attaching proteins to nicotine molecules. After ‘vaccination’ the body reacts to the nicotine in the same way as it reacts to pathogens.
Suggest how the ‘nicotine vaccine’ might help wean a smoker off nicotine. [ 2 marks ]
-if nicotine taken, antibodies bind to nicotine molecules
-making them too large to get to brain / making them ineffective
Impacts of cilia not working
-it allows dirt and pathogens down into lungs which increases risk of infection
-mucus builds up over time which increases coughing
Why do bacteria and viruses make us feel ill?
-Bacteria produces toxins
-Vireuses damage cells
Why can’t antibiotics treat viral infections
-Viruses live inside cells
–so drug cannot reach the virus
-as drug would damage body cells
Explain why there has been a large increase in the number of antibiotic-resistant strains of bacteria?
-doctors overprescribe antibiotics so there is an overuse
-mutation occurs in bacteria
-(when antibiotic used) only resistant bacteria survive and non-resistant bacteria are killed
-so there is reduced competition
-so the resistant bacteria can live on and reproduce
Explain how a vaccine for HIV could work to prevent a person developing HIV infection.
-Use a dead or inactivated sample of HIV and inject it into the person’s bloodstream/body
-This would trigger white blood cells to produce specific antibodies against inactive virus
-If a person is infected with HIV, their white blood cells would produce antibodies at a faster rate to destroy the HIV quickly
A person with late stage HIV infection has AIDS
Suggest how the monoclonal antibody for HIV helps prevent a person infected with HIV developing AIDS
[3 marks]
-Monoclonal antibody is complementary to the HIV antigen
-M.A attach to all of the HIV antigens
-so HIV cannot bind to human cells
Adult hornet moths lay eggs that hatch into larvae.
The larvae of the hornet moth:
* live inside the roots of trees
* use the tree roots as a source of food * cause damage to the tree roots.
Explain why a tree might die if the roots of the tree are damaged.
[6 marks]
*less absorption of water
- less water so lower rate of photosynthesis
- so less glucose produced
- for respiration/energy release
so less cellulose produced so fewer cells walls/cells made
-so fewer amino acids produced to make new proteins
- cells lose turgidity
- less absorption of (named) ions / minerals
-fewer nitrates so fewer proteins made for growth - fewer magnesium ions so less chlorophyll produced
-so lower rate of photosynthesis - damage to phloem
- less transport of sugars to root cells
-for respiration/energy release - damage to xylem
-less water transported (to cells)
-fewer nitrates reach cells - so fewer proteins made for growth
- fewer magnesium ions reach cells
- so less chlorophyll produced
-less magnesium/chlorophyll so lower rate of photosynthesis
