Cell Recognition And The Immune System Flashcards
Proteins on molecules enable the immune system to identify …x4
Pathogens
Cells from other organisms of the same species
Abnormal body cells
Toxins
What is an antigen
Foreign protein generate an immune response when detected by lymphocytes in the body
Define a pathogen
A microorganism that can cause diseases
Name x4 types of pathogen
Bacteria
Virus
Fungi
Protists
What are abnormal body cells
Cancerous or pathogen infected cells that have abnormal antigens on their surface that trigger an immune response
Are toxins molecules or cells
Molecules
Why can antigen variability be a problem
Antigens change frequently due to mutations
This is a problem because lymphocytes and memory cells produce a specific immune response
Bind to one antigen once changed it can no longer bind
What is the bodies first line of defence
Skin
Which white blood cells which are specific and which are non-specific
Phagocytes - non-specific
Lymphocytes- specific
What type of white blood cell is a macrophage
Phagocytes
Is phagocytosis specific or non-specific
Non-specific
Where are phagocytes found
Tissue
Blood
Stage 1 of phagocytosis
Pathogens release chemicals
Phagocytes follow the trail and moves towards these cells
The phagocytes have many receptors that will attach to the chemicals or antigens on the pathogen
The phagocyte changes shape to move around and engulf the pathogen
Once engulfed the pathogen forms a phagosome and fuses with a lysosomes
The lysozymes digests the pathogen
The phagocyte then presents the pathogens antigens on it surface to activate other immune system cells.
The phagocyte is an anti-gen presenting phagocyte
What is the purpose of disulphide bridges in a antibody
Joins two polypeptide chains
What type of cell are T-lymphocytes
White blood cell
Are T-cells specific or non-specific
Specific
Where are lymphocytes made
In bone marrow
What is cell-mediated response
The response involves T-cells and body cells
No antibodies
What is an antigen presenting cell
Any cells that presents a non-self antigen on the cell MEMBRANE
Name x2 antigen presenting cells
Macrophages
Cancer cells
How do T-cells work
They have receptors which attach onto the antigens on an antigen-presenting cell
One attached they are activated and divide by mitosis to produce large number of clones
The cloned helper T-cells differentiate into different cells
What can T-cells do x3
Helper T-Cells stimulate phagocytes
Activate B-cells to secrete anti toxins
Cytotoxic T-Cells kill foreign cells
How do cytotoxic T-Cells work
Release perforin which embeds into cell surface membrane and make a pore
Because any substance can leave or enter the cell dies
Are B-lymphocytes specific or non-specific
Specific
What does humoral response involve
B cells
Antibodies
How do B-Cells work
Antigens binds to antibody on B-cells
B cell takes in antigen by endocytosis then presents it on its cell surface membrane
BCells collide with T-cells receptor which activates B-cell to go through clonal selection
It undergoes mitosis to make cells that differentiate into plasma cells or memory B-cells
What do memory B-cells divide into
Plasma cells
What type of protein structure are antibodies
Quaternary
4 polypeptide chains
Structure of antibodies
Light chain
Heavy chain
Variable region
What binds are in an anti body
Disulphide bridges
What is agglutination
Antibodies have 2 binding sites so can bind to 2 antigens
This causes the pathogens to be clumped together
Advantage of agglutination
Makes it easier for phagocytes to locate and destroy pathogens
What is passive immunity
When antibodies made by a different organism are added to the body
Two types of passive immunity
Natural - E.g. antibodies through mothers milk
Artificial - E.g. injected with antibodies
Two types of active immunity
Natural - become immune after catching a disease
Artifical - immune after been given a vaccination
Active vs passive immunity x4 differences
Expose to antigen needed vs non expose needed
Take time for protection to develop vs immediate
Memory cells produced vs no memeory cells
Protection long term vs short term
X2 uses of monoclonal antibodies
Pregnancy tests
Anti-cancer drugs targeting cancer cells
Where does HIV replicate specifically
In helper T-Cells
How does direct ELISA test work
Add antigen of pathogen to the well
Add antibody with enzyme attached and complimentary shape to the antigen being tested
Wash the well to remove unbound antibody
Substrate for the enzyme is added
If detection antibody is present the enzyme reacts with substrate to give colour change
Explain indirect Elisa test
HIV antigens bound to the bottom of the well
Sample of blood plasma is added
If HIV specific antibodies are present they will bind to to HIV antigens
Wash well
Second set of antibodies complimentary to specific HIV antibodies are added
Well is washed
Substrate is added if solution changes colour than HIV specific antigen a re present and patient has HIV
How is HIV replicated x5
Attachment protein attach to receptors on lymphocytes
Capsid and RNA enters cell
Reverse transcriptase converts RNA to DNA
Viral proteins produced
Virus particles assembles and are released from cell
What further test can be done to investigate effectiveness of monoclonal antibody x2
Test on other mammals to check for side effects
Test on healthy humans for side effects
Investigate difference concentration to find suitable dosage
How does HIV replicate once inside the cell detail x4
RNA is converted to DNA using reverse transcriptase
DNA is incorporated into the helper T-Cell DNA
DNA is transcribed into HIV mRNA
HIV mRNA translated into viral proteins
How can determining the genome of a virus could allow scientist to develop a vaccine
Could identify proteins
They could then identify the antigens to use in the vaccine
How do B cells work
B cell antibody bond to the pathogens complimentary antigen
The B cell the clones
The plasma cells releases antibodies
B cell the develops into memory cells
What is a monoclonal antibody
Antibody produced from cloned plasma B cell
Why is vaccine nation quicker upon re infection
B cells specific to antigen produced by mitosis
B cells produce plasma and memory cells
The second set of antibodies produced at a higher concentration and more quickly
How does a antigen presenting cell stimulate the production of an antibody against a virus antigen x4
Helper T-Cell binds to the antigen on the antigen presenting cell
The helper T-cell stimulates a specific B cell
B cell divides by mitosis
To produce plasma cells that release antibodies
What is an antibody
A protein specific to an antigen that is produced by B cells
Types of phagocytes
Macrophages
Neutrophils
What is the difference between macrophage and neutrophil
Macrophages can become and antigen presenting cell
But both still carry out phagocytosis
What do phagocytes release after engulfing a pathogen and what is its role
Chemical can cytokines
Signals to other phagocytes and the immune system cells to the site of infection
What 3 things does the specific immune system involve
Antibodies
B and T lymphocytes
What type of proteins are antibodies
Glycoproteins
Which cell produces antibodies
B lymphocytes
Antibodies are part of the ….. response
Humoral
What type of response is Tcells and why
Cell mediated response
On respond to antigens presented on antigen presenting cells
X4 role of T-cells
Activate B lymphocytes
Stimulate macrophages to perform phagocytosis
Some became memory cells
Some become cytotoxic T -cells
How does vaccine lead to production of antibodies x5
Vaccine contains antigen from pathogen
Macrophages present antigen on its surface
Specific helper T-cells with complimentary receptors proteins bind to antigen
T-cells stimulate B cells
B cells divide to give plasma cells
B cells secrete large amount of antibodies
B cells divide to form clone which secrete the same antibody
Difference between active and passive immunity x5
Active in loves memory cells passive does not
Active involves production of antibody by memeory cells passive does not
Passive involves introduction of antibody from outside sources
Passive is short term because antibody is broken down
Advantage of programmed cell death
Prevents virus replicating
Antibodies are which biological molecule
Protein
E all in how antigen binds to antibody (using key words)
Antibody has specific TERTIARY structure
Has BINDING SITE that only binds to one ANTIGEN
Antigen to this antibody is ONLY found on these cells
So antibody BINDS to form ANTIGEN-ANTIBODY COMPLEX
