3.2.4 Cell Recognition And The Immune System Flashcards
Definition of pathogen , how it works
Organism that cause disease
E.g. Bacteria, viruses and fungi.
Release toxin
Kill cell / tissue
Where is toxin produce?
Bacteria
What is physical and chemical defence?
Physical defence (non special)
Skin, saliva, membrane lining, Cilia
Chemical defence
Stomach acid, urine, tear, mucus ,sweat
Two types of leukocytes
Phagocytes (non-specific)
Lymphocyte (specific)
T cell - cell mediated : only antigen on surface of the cell, produce in bone marrow mature in thymus gland
B cell - humoral : antigen in body fluid, produce and mature in bone marrow
What are those surface molecule for identifying they are nonself cell?
Pathogens
Cell from other organisms or same species (organ transplant)
Abnormal body cell (tumour)
Toxins
Why and how antigen variability created, fix
DNA mutate frequently shape of antigen will change
Previous immunity is no longer effective on memory cells, have memory of old antigen shape
Influenza virus mutates very quickly new f
So new flu vaccine create each year
Process of phagocytosis
- Chemicals are released by the pathogen.
- The phagocytes are attracted to this chemical(foreign substance) and move toward to pathogen
- The phagocyte engulf the pathogen forming vesicles (phagosome)by endocytosis.
- Lysosome found in the phagocyte , Move to vesicles and fused.
- Lysozyme.(hydrolytic, enzyme) in lysosome digest, the pathogen
- They display the important antigen on the self-surface membrane.
Composition of blood
Plasma
White blood cell (leukocyte)
Platelets (thrombocytes)
Red blood cell (Erythrocytes)
What is antibody?
Antibody or protein produced by the plasmid (B lymphocytes) which has a big cytoplasm and rough ER
The structure of antibody
Y shape
4 Disulphide bond
Specific tertiary structure
Variable side only complimentary to one specific antigen due to specific amino acid sequence
Only bind to form an antigen antibody complex with specific antigen
Quaternary structure , we got two or more polypeptide chain
When an antigen bind to an antibody, what is formed
Antigen antibody complexed
What is clump to create a network of antigen antibody complex so that phagocytosis occur?
Agglutination
Which blood type is the universal donor and the universal recipient
Universal donor: O
Universal recipient : AB
Advantage and disadvantage of specific non-specific immune response
Non-specific: fast, all pathogens, cannot get rid
Specific : slow, target specific pathogen, get rid
Four jobs of T cell
Stimulate more phagocytosis by releasing cytokines
Helper T cell : activate B cell
Cytotoxic T cell / killer T cell : Dealing with infected cell by releasing cytotoxic chemical (Cytotoxin) (E.g. perforin)
Memory T cell: rapidly divide when previous pathogen encounter again
Two jobs of B cell
Plasmid cell : make complimentary antibody agglutinate pathogens
Memory B. Cells : stay in the body allowed body produce antibody rapidly for cloning and become plasmid cell
Whole immune response process, including B cell and T cell
Both T and B is out is produced by bone marrow. when invading pathogen encounter in a system, then present antigen on self surface membrane. The antigen presenting cells’ antigen will be bind with complimentary antibody chosen by clonal selection. T cell will be activated and stimulated the cell division process of mitosis, and four types of T cell will be produced.
B cell could bind with antigen in blood through it through clonal selection antigen is being internalise and present on the protein of self-surface membrane. Then T-helper cells, which is complimentary to the antigen, will bind with it. This activated B-cell, which cause division process of mitosis and two type of B cell is produce.
Definition of monoclonal antibody
Cell that’s been cloned and produce same antibody that bind with same specific antigen
What are the industry and medical used of monoclonal antibodies
Targeting medication to specific cell types
Medical testing
Medical diagnosis using Elisa
Difference between direct monoclonal, antibody therapy and indirect monoclonal antibody therapy
Direct
Monoclonal antibodies are produced specific to the antigen on the target of cell
Prevent the cell uncontrolled growth (inhibit growth) by blocking signalling pathways in them, so they can’t divide and died
Indirect
cytotoxic, drug is attached it to the monoclonal antibody and antibody attach to the antigen on the target to kill the cell
Pregnancy testing
Reaction site
Free antibody (Anti- HCG antibodies) to trap HCG
Testing site
Fixed antibodies (Anti HCG antibody) to trap HCG
CONTROL SITE
Fixed antibodies (antimouse antibodies) do you trap free excess antibodies
Liquid move up through capillary action
How color reaction in pregnancy test happen?
Substrate complex with dye molecule
Turn into coloured products
How are monoclonal antibody made artificially?
They are made artificially by injected, nonself cell into mouse
Fuse the plasma cell ( from the mouse) with the tumour cell
So it become hybridoma cells
Which could make more monoclonal antibody
Describe the stages of her pregnancy test work (exam Q)
What in reaction site the free Ab from the mouse carry enzyme that find with HCG to the test area
In the test side if they got pregnant with enough HCG will bind with the antibody
The product of enzyme substrate complex is coloured
Purpose of control site in pregnancy test
To prove if the test work
Prevent false negative result
What is the ELISA test for, equipment
Use for diagnosing disease like flu chlamydia hepatitis
Identify the presents and concentration of an antigen or an antibody in the patient sample
Who is plasma cell body fluid not the red blood cell (no colour)
Use of multiwell plate
What is the control for ELISA to test for?
Check colour change, only happen due to presence of enzyme no other factor
Rinsing between stages are effective
Steps of ELISA test
HIV, antigen molecule attaches to test well in a dish
Sample of blood plasma is add to the well. If HIV antibody present they bind with HIV antigen
Well is wash to remove excess antibodies
A second Antibody with an enzyme attached. It is then at the spine, specifically to HIV antibody.
The well is washed again to remove any unbounded Antibody
Yellow solution is add
Change to blue if enzyme is present
HIV antibody present, HIV positive
Ethical use of monoclonal antibodies
Use of mice
Deliberately induce cancer, which cause suffering
Death in treatment of multiple sclerosis
Patient should have full knowledge of risk and benefit before giving permission (inform consent)
Danger of testing the safety of new drug
Sever multiple organ failure due to T cell, overproducing chemical which stimulate immune response that attack body tissue
How do you know the concentration of antibodies elisa test?
Dark of the colour, high concentration of Ab
Pros of monoclonal antibodies
Successfully treat a number of disease
Vaccination
Injecting inactivated pathogen
Double trial and lab trial, clinical trial on healthy people
Create memory cell for a real infection
Definition of vaccination
Involve injection of antigen that have been isolated from a dead attenuated micro organism
This induced a primary immune response in an individual produce memory cells / plasma cell/ antibodies without them, suffering the symptoms of disease. Provide artificial immunity
Describe two stages of immune responds
Primary: by vaccination / actual infection with pathogen
Secondary responds : faster quicker/ more plasmid an antibody
Definition of herd immunity
Sufficiently large proportion of the whole population has been vaccinated
Set of pathogen is less easy to spread from person to person
Protect those who have not been vaccinated , not immunised
Ethical issue of using vaccines
Use of animal in testing
Side-effect causing long-term harm
How many volunteers vaccines trail risk
Trial a new vaccine with unknown have only in a country where the target this is common
Compulsory vaccination to be fully effective
Economic concern : should expensive vaccine program, continue when a disease is almost eradicated, even though this means less money for the treatment of other disease
Balance between individuals health risk and advantage for larger population
Why vaccination might not work?
People with defective immune system (age /chemotherapy)
Individual may develop disease , and infect the other, as there is no enough memory cell
When pathogen mutate frequently is difficult to develop a vaccine against them (antigenic variability)
Pathogen that hide from the immune system (HIV is hard to detect in early stages)
Individual may have objection against vaccines (religious reason)
Definition of antigenic variability
A pathogen mutate frequency
Which can cause is surface antigen to change
The Fessenden suddenly become ineffective
Because the antibody of the immune system can no longer recognise / not complimentary to the antigen
Definition of passive immunity
Introducing or inserting monoclonal antibody into an organism from an outside source
Do you have no contact with pathogen or antigen?
Definition of active immunity
Direct contact with pathogen or its antigen
Stimulating the bodies immune system to produce its own antibodies
Give examples of natural and artificial ways of giving active immunity and passive immunity
Active
Natural : actual pathogen infection
Artificial : vaccine injection of antigen
Passive
Natural : maternal antibodies from breast milk
Artificial : blood transfusion , monoclonal, antibody injection
Compare active and passive immunity
Ab secreted by plasma cell vs Ab introduced into body from outside
Long-term because antibody produce in response to antigen, memories are made vs short term because no memory, made antibody will break down
Takes longer to develop vs fast acting
Feature of a successful vaccination
Financially available
Few side-effects
Ways of producing storing and transport
Ways of giving administering the vaccine properly (training staff)
Available in sufficient quantity to vaccinate most of the population to result in herd immunity
Structure of HIV
Attachment protein
Lipid envelope
Matrix
Capsid
Genetic material (RNA)
Reverse transcriptase
What is HIV?
Retrovirus
A group of viruses where the virus is able to insert is genetic material into the host cells DNA, using an enzyme called the reverse transcriptase
HIV infection
Enter the bloodstream and circulate
Virus binds using attachment protein to receptor protein (CD4) on the surface of T helper cell
The virus lipid and the fused with the cell surface membrane
The capsid it breaks down, and this released a genetic material and enzyme into the cell
Reverse transcriptase, convert RNA to DNA
The viral DNA moved into the nucleus through a nuclear pore and is inserted into the host cell DNA by integrase
the HIV DNA is transcripted into mRNA, and then translate it into viral protein
These new viral particles are assembled and bud off from the cell surface membrane it to infect more cell
Destroy T-helper cells
How HIV cause AIDS
When we are infected with HIV, we are HIV positive
Normal 800 to 1200 helper T cell
Abnormal 200
Immune system stop functioning, unable to produce adequate immune response
Suspectible to other infection
Lead to AIDS acquired immune deficiency syndrome
Symptoms are related to the infection. A person developed as a result of having a damage immune system which can’t fight off infection as well.
Secondary infection, cost death
Exam Q: after being infected with HIV and number of years later, individual develop a number of Audrey infection, explain why?
HIV replicate, destroy helper, T cell
Helper T cell number decrease
Less cell to activate B cell
Less plasma cell produce
Less antibody made against pathogen for second infection
Less memory cell made
Unable to fight secondary infection
Some important point for HIV
AIDS is a set of symptoms that result from low helper, T cell, number due to rapidly replicating, HIV in a patient.
It is possible to be HIV positive, but not having AIDS yet
People with AIDs must be HIV positive
How does antibiotic works? Example too
Antibiotic works in many ways but one function they have is prevent bacteria from making cell wall. Water are consistently enter bacteria cell by osmosis. without cell wall bacteria will lysis if too much Water enters. antibiotics like penicillin, inhibit, certain enzyme required to synthesis and assembly The cross linkage in the murein cell wall. Weakening them making them unable to withstand high pressure caused by water entering the cell
Why antibiotics does not affect the virus?
have no cell wall
No metabolic process
Cannot reach the virus getting into the cell
Only Damage host cell would kill the virus
What is antibiotic resistant and how does it develop?
There is genetic mutation in the base sequence
Change protein
Change characteristic
Penicillin, kill Audiard bacteria so they can’t pass on this survive
Antibiotic resistant bacteria, survive and pass on
Two type of test statistic?
Standard deviation
Student t-test
Keyword for null or alternative hypothesis
Statistically significant difference
Exam question asking about statistic test calculation
Compare P value to 0.05
Statistically significant difference or not
Reject or accept null hypothesis
4 type of cell that can stimulate an immune response
Pathogen
Abnormal body cell
Antigen- presented cell
cell from other organism of same species
