3.2.4 - Cells - Cell recognition and the immune system Flashcards
which cells identify the presence of pathogens and potentially harmful foreign substances in the body and to destroy or neutralise them to prevent harm?
lymphocytes
what are antigens made from?
proteins
what do different surface molecules enable them to identify?
pathogens (e.g. bacteria, fungi or viruses such as HIV)
cells from other organisms of the same species (harmful for those with organ transplants)
abnormal body cells (e.g. cancer cells)
toxins
what can each different shape lymphocyte do?
each one can recognise a different shaped antigen
when are lymphocytes made?
when you are a foetus
what is the definition of an antigen?
foreign proteins that generate an immune response by lymphocyte cells when detected in the body
where are antigens located?
on the surface of cells
what happens if a mutation occurs in the gene which codes for the antigen?
the shape of the antigen will change
what happens to the previous immunity to a pathogen if there is a mutation of the antigens?
any previous immunity to this pathogen (either naturally
through prior infection or artificially through vaccination) is
no longer effective, as all the memory cells in the blood will
have a memory of the old antigen shape
this is antigen variability
what is an example of a chemical barrier that pathogens have to get past?
stomach acid
what is an example of a physical barrier that pathogens have to get past?
skin
what line of defence are the white blood cells?
if the pathogen enters the blood then the white blood cells are the second line of defence
what type of white blood cells are responsible for the non-specific response?
phagocytes
what type of white blood cells are responsible for the specific response?
lymphocytes
what type of white blood cell is a phagocyte?
macrophage
where are phagocytes found?
found in the blood and in tissues
is phagocytosis a specific or non-specific response?
a non-specific response
what is the process of phagocytosis?
phagocytes are in the blood and tissues and any chemicals
or debris released by pathogens or abnormal cells attract
the phagocytes and they will move towards these cells
there are many receptor binding points on the surface of phagocytes, they will attach to chemicals or antigens on the pathogen via these receptors
the phagocyte changes shape to move around and engulf the pathogen, once engulfed, the pathogen is contained with a phagosome vesicle
a lysosome within the phagocyte will fuse with the phagosome and release its contents, the lysozyme enzyme is released into the phagosome
this is a lytic enzyme which hydrolyses the pathogen, this destroys the pathogen, the soluble products are absorbed and used by the phagocyte
where are all lymphocytes made?
made in the bone marrow
where do T cells mature?
in the thymus
which cells does the cell-mediated response involve?
T cells and body cells
how is the cell mediated response specific?
because T cells respond to antigens on the surface of cells
what are Antigen-Presenting Cells (APC)?
any cell that presents a non-self antigen on their surface
what are examples of APC?
infected body cells presenting viral antigens on their surface
a macrophage which has engulfed and destroyed a pathogen presenting the antigens on their surface
why is cell mediated response described as ‘cell-mediated’?
because T cells only respond to antigens which are presented on cells (APC), and not antigens detached from cells and within body fluids, such as the blood
what is the process of cell mediated response?
1 - once a pathogen has been engulfed and destroyed by a phagocyte, the antigens are positioned on the cell surface, this is now called an antigen-presenting cell (APC)
2 - helper T cells have receptors on their surface which can attach to the antigens on APC
3 - once attached this activates the helper T cells to divide by mitosis to replicate and make large numbers of clones, cloned helper T cells differentiate into different cells
what are the different cells that cloned helper T cells differentiate into during cell mediated response?
some remain as helper T cells and activate B lymphocytes
some stimulate macrophages to perform more phagocytosis
some become memory cells for that shaped antigen
some become cytotoxic T cells (killer T cells)
what do cytotoxic T cells do?
destroy abnormal or infected cells
how do cytotoxic cells destroy abnormal or infected cells?
they release a protein, perforin, which embeds in the cell surface
membrane and makes a pore (a hole) so that any substances
can enter or leave the cell and this causes cell death
when are cytotoxic T cells most common?
in viral infections because viruses infect body cells, body cells are sacrificed to prevent viral replication
where do B cells mature?
in the bone marrow
what does the humoral response involve?
the response involving B cells and antibodies
how are antibodies transported around the body and are they soluble?
antibodies are soluble and transported in bodily fluids
what happens in the process of B cell activation?
antigens in the blood collide with their complementary antibody on a B cell
the B cell takes in the antigen by endocytosis and then presents it on its cell surface membrane
when this B cell collides with a helper T cell receptor, this activates the B cell to go through clonal expansion and differentiation (clonal selection)
B cells undergo mitosis to make large numbers of cells, these differentiate into plasma cells or memory B cells
do plasma cells make antibodies?
yes
how do B memory cells make antibodies?
divide rapidly into plasma cells when reinfected with the same pathogen to make large numbers of antibodies rapidly
how long can memory B cells live for in your body?
decades
how long do plasma cells live for?
short lived
what do memory B cells do instead of making antibodies?
they will divide by mitosis and make plasma cells rapidly if they collide with an antigen they have previously encountered
what is active immunity?
where large numbers of antibodies being produced so rapidly that the pathogen is destroyed before any symptoms can occur
what is the definition of an antibody?
quaternary structure proteins made up of four polypeptide chains
what does every antibody have that is different?
each different antibody has a different shaped binding site, which
is the variable region
the shape of the antigen-binding site is unique to the shape of a particular antigen
what is the process called that makes lots of antibodies clump together?
agglutination
why is agglutination important?
this makes it easier for phagocytes to locate and destroy the pathogens
what is passive immunity?
antibodies are introduced into the body
the pathogen doesn’t enter the body, so plasma cells and memory cells are not made
e.g. antibodies passed to a fetus through the placenta
or through breast milk to a baby
is passive immunity long term immunity?
no
what is active immunity?
active immunity is when immunity is created by your own immune system following exposure to the pathogen or its antigen
what are the two types of active immunity?
natural and artificial
what is natural active immunity?
following infection and the creation of the body’s own antibodies and memory cells
what is artificial active immunity?
following the introduction of a weakened version of the pathogen or antigens via a vaccine
what are vaccines?
small amounts of weakened or dead pathogens or antigens are introduced in the mouth or by injection
how does having a vaccine cause your body to produce antibodies and become immune to that specific pathogen?
- exposure to the antigens activates the B cell to go through clonal expansion and differentiation (clonal selection)
- B cells undergo mitosis to make large numbers of cells, these differentiate into plasma cells or memory B cells
- plasma cells make antibodies
- B memory cells divide rapidly into plasma cells when re-infected with the same pathogen to make large numbers of antibodies rapidly
what is herd immunity?
if enough of the population is vaccinated the pathogen cannot spread easily amongst the population
who does herd immunity protect?
provides protection for those who are not vaccinated e.g those already too ill to have a vaccine or who have a lowered immunity, or those who are too young
what is a monoclonal antibody?
a monoclonal antibody is a single type of antibody that can be
isolated and cloned
what are antibodies made from?
proteins which have binding sites complementary in shape to certain antigens
what are some uses of monoclonal antibodies?
medical treatment
medical diagnosis
pregnancy tests
how can direct monoclonal antibody therapy be used to help deliver medication to cancer patients?
some cancers can be treated using monoclonal antibodies which are designed with a binding site complementary in shape to the antigens on the outside of cancer cells
the antibodies are given to the cancer patient and attach to the cancer cells, while the antibodies are bound to the cancer antigens,
this prevents chemicals from binding to the cancer cells which enables uncontrolled cell division
therefore, the monoclonal antibodies prevent the cancer cells from growing, and as they are designed to only attach to cancer cells they do not cause harm to other normal cells
how can indirect monoclonal antibody therapy be used to help deliver medication to cancer patients?
cancer can also be treated with monoclonal antibodies complementary in shape to the antigens on the outside of cancer cells which have drugs attached to them
these cancer drugs are therefore delivered directly to the cancer cells and kill them
this reduces the harmful side effects that traditional chemotherapy and radiotherapy can produce, this is often referred to as ‘bullet drugs’
what can monoclonal antibodies be used to test for?
pregnancy
influenza
hepatitis
chlamydia
prostate cancer
how does an ELISA test use three different types of antibodies in a pregnancy test?
first mobile antibody, complementary to the antigen being tested for, and has a coloured dye attached
a second antibody complementary in shape to the antigen is immobilised in the test
a third antibody is immobilised and is complementary in shape to the first antibody
what are the ethical issues to do with monoclonal antibodies?
creating monoclonal antibodies requires mice to produce the antibodies and tumour cells, which leads to ethical debates
where do viruses replicate?
inside cells
why can viruses not be destroyed by antibiotics?
they have no cell wall
what is the core in HIVs structure?
genetic material (RNA) and the enzyme reverse transcriptase, which are needed for viral replication
what is the capsid in HIVs structure?
the outer protein coat
what is the envelope in HIVs structure?
extra outer layer, made out of lipids taken from the host’s cell membrane
what are the protein attachments in the HIV structure?
on the exterior of the envelope to enable the virus to attach to the host’s helper T cell
how is HIV transported through the body?
through the blood until it attaches to a CD4 protein on the helper T cells
during HIV replication what fuses with the helper T cell membrane?
the HIV protein capsule then fuses with the helper T
cell membrane, enabling the RNA and enzymes from HIV
to enter
what does the HIV enzyme reverse transcriptase do?
copies the viral RNA into a DNA copy and moves to the helper T cell
nucleus, this is why it is called a retrovirus
what do helper T create during HIV replication?
creates viral proteins to make new viral particles
how does AIDS occur from HIV?
AIDS is when the replicating viruses in the helper T cells interfere with the normal functioning of the immune system
what causes people to die from AIDS?
the destruction of the immune system that leads to death, rather than HIV directly
why are people with HIV more vulnerable to other diseases?
with the helper T cells being destroyed by the virus, the host is unable to produce an adequate immune response to other pathogens and is left vulnerable to infections and cancer
what are symptoms of AIDS?
skin - tumors
gastrointestinal - chronic diarrhea
central - meningitis
What is the function of reverse transcriptase?
It synthesizes DNA from an RNA template
This enzyme is crucial for retroviruses like HIV.
What are the components of a virus mentioned?
- Transmembrane glycoprotein
- Capsid
- Genetic material
These components are essential for the structure and function of viruses.
What does HIV target in the human body?
Helper T cells
HIV specifically infects and destroys these immune cells.
What is the normal range of helper T cells per mm³ in healthy humans?
800 - 1200 helper T cells
This range indicates a functioning immune system.
What T cell count indicates progression to AIDS?
Less than 200 helper T cells
This low count signifies a severely weakened immune system.
What is the consequence of HIV on B cells?
B cells cannot be stimulated to produce antibodies
This leads to impaired immune response.
What happens to cytotoxic T cells and memory cells during HIV infection?
They are sometimes infected and destroyed
This results in inadequate immune response.
What results from the destruction of helper T cells by HIV?
Inadequate immune response
This leaves the body vulnerable to infections and cancers.
In AIDS patients, what types of infections are they prone to?
- Infections of the lungs
- Infections of the intestines
- Infections of the brain
- Infections of the eyes
These infections are common due to the weakened immune system.
True or False: It is HIV that directly causes death in AIDS patients.
False
It is secondary infections and illnesses, not HIV, that lead to death.
What is the role of the protein capsid in HIV infection?
Fuses with the cell membrane
This process allows the HIV virus to enter the host cell.
What happens after HIV RNA and enzymes enter the T cell?
The mRNA leaves the nucleus of the host cell through nuclear pores
It utilizes the cell’s protein synthesis mechanisms to create HIV particles.
Where is the new DNA from HIV moved after it is created?
Into the helper T cell’s nucleus
This insertion is into the cell’s DNA.
What does the HIV DNA in the nucleus create?
mRNA using the cell’s enzymes
This mRNA contains instructions for making new viral proteins.
What are attachment proteins on HIV that bind to T helper lymphocytes?
gp120 molecules
These proteins specifically bind to CD4 receptor proteins.
What process occurs when HIV particles bud away from the helper T cell?
They form their lipid envelope
This occurs by taking a piece of the cell’s cytoplasmic membrane.
What enzyme does HIV use to convert its RNA to DNA?
HIV reverse transcriptase
This is a critical step in the HIV replication process.
What are lymphocytes?
Lymphocytes are cells in the immune system that identify and destroy pathogens and harmful substances
Lymphocytes are crucial for the body’s immune response.
What triggers a response to destroy a non-self cell?
The detection of a non-self cell triggers a response to destroy it
This is a key function of the immune system.
What types of entities can lymphocytes identify?
- Pathogens (e.g. bacteria, fungi, viruses)
- Cells from other organisms of the same species
- Abnormal body cells (e.g. cancer cells)
- Toxins
Recognition of these entities is vital for immune defense.
How many different types of lymphocytes does the human body have?
10 million different types of lymphocytes
Each type can recognize a different shaped antigen.
What happens to lymphocytes that are complementary to self-cells?
They die or production is suppressed to prevent attacking self-cells
This process occurs during fetal development and after birth.
Where are new lymphocytes made after birth?
In the bone marrow
New lymphocytes are produced throughout life.
What causes autoimmune diseases?
The production of lymphocytes that attack self-cells
This can occur if the process of lymphocyte selection fails.
Fill in the blank: Lymphocytes can recognize _______ which are unique to pathogens.
[antigens]
True or False: Lymphocytes are produced only during fetal development.
False
Lymphocytes are also produced in the bone marrow after birth.
What is the role of surface molecules on lymphocytes?
To identify different types of cells, including self and non-self cells
These molecules are usually proteins with unique 3D structures.
What are antigens?
Foreign proteins that generate an immune response by lymphocyte cells when detected in the body.
Antigens are located on the surface of cells.
What type of cell is a macrophage?
A type of immune cell that engulfs and digests foreign particles and pathogens.
What are the two types of B-cells mentioned?
- Effector B-Cell
- Memory B-Cell
What are lymphocytes?
A type of white blood cell that is part of the immune system.
What is antigen variability?
The phenomenon where pathogenic DNA mutates frequently, changing the shape of the antigen.
This can render previous immunity ineffective.
What happens if a mutation occurs in the gene coding for an antigen?
The shape of the antigen will change, making previous immunity ineffective.
Why does a new flu vaccine have to be created each year?
Because the influenza virus mutates and changes its antigens very quickly.
Fill in the blank: _______ are proteins produced by B-cells that help neutralize pathogens.
[Antibodies]
What type of T-cell is responsible for killing infected cells?
[Killer T-Cell]
What type of T-cell helps activate other immune cells?
[T Helper Cell]
What is the role of naive B-cells?
They are immature B-cells that have not yet encountered an antigen.
What is the second line of defence in the immune response?
White blood cells
They act after the initial chemical and physical barriers like skin and stomach acid are breached.
What are the two main types of white blood cells involved in the immune response?
- Phagocytes
- Lymphocytes
What is the function of phagocytes in the immune system?
Responsible for the non-specific response
What is the role of lymphocytes in the immune system?
Responsible for the specific response
What is phagocytosis?
A non-specific response where phagocytes engulf and destroy pathogens
What type of white blood cell is a macrophage?
A type of phagocyte
Where are phagocytes found in the body?
In the blood and in tissues
Fill in the blank: Phagocytosis is triggered by the detection of any _______ cell.
non-self
What happens to a non-self cell during phagocytosis?
It is engulfed and destroyed
What structures are involved in the process of phagocytosis?
- Phagosome
- Lysosome
- Phagolysosomes
What is the function of lymph nodes in the immune system?
They filter lymph and house immune cells
What organ is responsible for producing lymphocytes?
Thymus
Fill in the blank: The bone marrow is responsible for producing _______ blood cells.
white
True or False: Phagocytosis is a specific immune response.
False
What is the outcome of exocytosis in the context of phagocytosis?
Release of soluble debris from the phagocyte
What are phagocytes?
Cells in the blood and tissues that engulf pathogens and debris
Phagocytes play a crucial role in the immune response.
What attracts phagocytes to pathogens?
Chemicals or debris released by pathogens or abnormal cells
This attraction is part of the immune response.
What happens when a phagocyte detects a pathogen?
It changes shape to move around and engulf the pathogen
This process is essential for phagocytosis.
What is a phagosome?
A vesicle formed around an engulfed pathogen
The phagosome contains the pathogen for further processing.
What role do lysosomes play in phagocytosis?
They fuse with the phagosome and release digestive enzymes
Lysosomes are critical for breaking down pathogens.
What is lysozyme?
A lytic enzyme that hydrolyzes pathogens
Lysozyme is released into the phagosome to destroy the pathogen.
What are the end products after a pathogen is destroyed by a phagocyte?
Soluble products absorbed and used by the phagocyte
These products can be utilized for the phagocyte’s own processes.
Fill in the blank: The process by which phagocytes engulf pathogens is called _______.
[phagocytosis]
True or False: Phagocytes have receptor binding points on their surface.
True
These receptors are essential for detecting and attaching to pathogens.
What happens to the pathogen after it is contained within a phagosome?
It is broken down by enzymes released from lysosomes
This breakdown is crucial for eliminating the pathogen.
What initiates the detection process of pathogens by phagocytes?
Receptors that detect viral proteins
These receptors are specific for recognizing pathogens.
What are lymphocytes?
White blood cells involved in the specific immune response
Lymphocytes are made in the bone marrow
Where do T cells mature?
Thymus
T cells are a type of lymphocyte
What is the cell-mediated response?
The response involving T cells and body cells
It is specific because T cells respond to antigens
List the organs of the immune system.
- Tonsils and Adenoids
- Thymus
- Lymph Nodes
- Appendix
- Bone Marrow
- Spleen
- Peyer’s Patches
- Lymphatic Vessels
Lymph Nodes are mentioned multiple times
What are antigen-presenting cells (APC)?
Any cell that presents a non-self antigen on their surface
APCs include infected cells, macrophages, transplanted organ cells, and cancer cells
What types of cells can present viral antigens?
Infected body cells
These cells present antigens on their surface
What role do macrophages play in the immune response?
Engulf and destroy pathogens, presenting antigens on their surface
Macrophages are a type of antigen-presenting cell
True or False: T cells respond to self-antigens.
False
T cells respond to non-self antigens
Fill in the blank: T lymphocytes are made in the _______.
Bone marrow
This is where all lymphocytes are produced
What distinguishes cancer cells in the immune response?
They have abnormal-shaped self-antigens
This can trigger an immune response
What is the primary characteristic of a cell-mediated response?
T cells respond only to antigens presented on cells (APC)
This response does not involve antigens detached from cells and within body fluids.
Name four key terms associated with the immune system.
- Bone marrow
- Thymus
- Memory cells
- Antigen-presenting cells
- Cytotoxic T cells
What happens to a pathogen after it is engulfed by a phagocyte?
The antigens are positioned on the cell surface, forming an antigen-presenting cell (APC)
This process is crucial for the activation of T cells.
How do helper T cells become activated?
By attaching to antigens on antigen-presenting cells (APC)
This attachment triggers their division by mitosis.
What are the fates of cloned helper T cells?
- Some remain as helper T cells to activate B lymphocytes
- Some stimulate macrophages for phagocytosis
- Some become memory cells for that antigen
- Some become cytotoxic T cells
Fill in the blank: The cells that present antigens to T cells are called _______.
antigen-presenting cells (APC)
True or False: Cytotoxic T cells are also known as killer T cells.
True
Identify the type of T cell that helps activate B lymphocytes.
Helper T cells
What is the role of memory cells in the immune response?
To remember specific antigens for future responses
Memory cells enable a faster response upon re-exposure to the same antigen.
Which cells stimulate macrophages to perform more phagocytosis?
Cloned helper T cells
What do Cytotoxic T cells do?
Cytotoxic T cells destroy abnormal or infected cells
They are crucial in the immune response, particularly during viral infections.
What protein do Cytotoxic T cells release to induce cell death?
Perforin
Perforin creates pores in the target cell’s membrane.
What is the role of perforin in the immune response?
Perforin embeds in the cell surface membrane and makes a pore
This allows substances to enter or leave the infected cell, leading to cell death.
Why are body cells sacrificed during viral infections?
To prevent viral replication
This is a protective mechanism to control the spread of the virus.
What symptom is associated with the action of Cytotoxic T cells during a cold?
Sore throat
The sore throat occurs because Cytotoxic T cells are destroying infected body cells in the throat.
Fill in the blank: Cytotoxic T cells are most commonly involved in _______ infections.
viral
They target cells that have been infected by viruses.
What do Granzymes do in the immune response?
Granzymes induce apoptosis in infected cells
They are serine proteases released by Cytotoxic T cells.
What is the TCR in the context of Cytotoxic T cells?
T-cell receptor
TCR is used by T cells to recognize antigens on infected cells.
True or False: Cytotoxic T cells only target cancerous cells.
False
Cytotoxic T cells primarily target infected cells, especially during viral infections.
What happens to a target cell after it is attacked by Cytotoxic T cells?
It undergoes cell death
This is a crucial step in eliminating infected or abnormal cells.
Where are all lymphocytes made?
Bone marrow
What is the primary function of B cells in the immune response?
Humoral response
What are antibodies?
Soluble proteins transported in bodily fluids
What does the term ‘humoral’ refer to?
Body fluids
What is clonal expansion?
The process of B cells undergoing mitosis to produce large numbers of cells
What do plasma cells produce?
Antibodies
What is the role of memory B cells?
To divide rapidly into plasma cells upon re-infection
How many different B cells are there approximately?
10 million
What is the mechanism by which a B cell takes in an antigen?
Endocytosis
What happens when a B cell collides with a helper T cell receptor?
The B cell is activated to undergo clonal expansion and differentiation
What are the two types of cells B cells can differentiate into?
- Plasma cells
- Memory B cells
Fill in the blank: The humoral response involves B cells and _______.
Antibodies
True or False: Antigens collide with antibodies on the surface of B cells.
True
What are memory B cells?
Memory B cells can live for decades in your body
How long do plasma cells typically last?
Plasma cells are short-lived
What do memory B cells do upon encountering a previously encountered antigen?
They will divide by mitosis and make plasma cells rapidly
What happens to antibody production during the secondary immune response?
Large numbers of antibodies are produced rapidly
What is active immunity?
This is when memory B cells produce antibodies rapidly upon re-exposure to an antigen
What is the primary immune response?
The response to the initial exposure to an antigen
What is the secondary immune response?
The response to a second exposure to the same antigen
Fill in the blank: Memory B cells do not make antibodies, rather they will divide by mitosis and make _______ if they collide with an antigen.
plasma cells
True or False: Memory B cells are responsible for the rapid production of antibodies during a secondary immune response.
True
What is the result of the rapid production of antibodies during the secondary immune response?
The pathogen is destroyed before any symptoms can occur
What is the term for the clones produced from memory B cells during an immune response?
Clone of ancestral cell
What does the concentration of antibodies indicate?
It indicates the strength of the immune response during primary and secondary exposures
What are antibodies?
Quaternary structure proteins made up of four polypeptide chains
Antibodies play a crucial role in the immune response.
What is the variable region of an antibody?
The part of the antibody with a different shaped binding site unique to a particular antigen
The variable region is shown in purple.
What is agglutination in the context of antibodies?
The process where antibodies bind to multiple antigens to clump them together
This facilitates easier identification and destruction of pathogens by phagocytes.
What are the main components of an antibody?
- Light chain
- Heavy chain
- Constant region
- Variable region
The constant region is shown in red.
True or False: Each antibody has the same shaped binding site.
False
Each antibody has a unique shape for its antigen-binding site.
Fill in the blank: Antibodies are _______ and can bind to multiple antigens.
flexible
This flexibility aids in the agglutination process.
What role do phagocytes play in relation to antibodies?
They locate and destroy pathogens that have been clumped together by antibodies
The clumping makes it easier for phagocytes to target pathogens.
What is passive immunity?
Antibodies are introduced into the body without pathogen entry, resulting in no long-term immunity.
Examples include antibodies passed to a fetus through the placenta or breast milk to a baby.
What are the key characteristics of passive immunity?
- Antibodies are introduced
- Pathogen does not enter the body
- No plasma or memory cells are made
- No long-term immunity
What is natural immunity?
Immunity developed through natural exposure to pathogens.
What is artificial immunity?
Immunity developed through medical intervention, such as vaccination.
What are antibodies?
Proteins produced by the immune system to identify and neutralize pathogens.
What is active immunity?
Immunity created by the body’s own immune system following exposure to a pathogen or antigen.
What are the two types of active immunity?
- Natural active immunity
- Artificial active immunity
What is natural active immunity?
Immunity developed after infection, leading to the creation of the body’s own antibodies and memory cells.
What is artificial active immunity?
Immunity developed after the introduction of a weakened pathogen or antigens via a vaccine.
What do vaccines introduce to the body?
Small amounts of weakened or dead pathogens or antigens
Vaccines can be administered orally or by injection.
What process do B cells undergo when exposed to antigens?
Clonal expansion and differentiation (clonal selection)
This process is crucial for the immune response.
What do B cells differentiate into after mitosis?
Plasma cells or memory B cells
Plasma cells are responsible for producing antibodies.
What is the role of plasma cells?
Make antibodies
Antibodies are crucial for identifying and neutralizing pathogens.
What happens to B memory cells during a secondary exposure?
They divide rapidly into plasma cells
This allows for a rapid production of antibodies.
Define herd immunity.
Protection for those who are not vaccinated when enough of the population is vaccinated
It prevents the spread of pathogens within a community.
What is the effect of herd immunity on disease spread?
It prevents the pathogen from spreading easily
This is especially important for vulnerable populations.
What happens when fewer people are immunized?
Disease spreads more easily
A lower immunization rate decreases herd immunity.
Fill in the blank: B cells undergo _______ to make large numbers of cells.
mitosis
Mitosis is essential for B cell proliferation.
True or False: Immunized people act as a barrier against infection.
True
Immunized individuals help protect the community from outbreaks.
What is the primary immune response?
The initial response to a pathogen upon first exposure
This response is typically slower than the secondary immune response.
What do initial exposures result in regarding antibodies?
A concentration of antibodies is produced
This concentration increases over time with exposure.
What is patient zero in the context of herd immunity?
The first person infected in an outbreak
Identifying patient zero can help trace the spread of disease.
What is a monoclonal antibody?
A single type of antibody that can be isolated and cloned
Monoclonal antibodies are created from identical immune cells that are all clones of a unique parent cell.
What are antibodies?
Proteins with binding sites complementary in shape to certain antigens
Antibodies play a crucial role in the immune response by recognizing and binding to specific antigens.
List three applications of monoclonal antibodies.
- Medical treatment
- Medical diagnosis
- Pregnancy tests
These applications leverage the specificity of monoclonal antibodies for targeted therapies and detection methods.
What is targeted medication in the context of monoclonal antibodies?
Direct monoclonal antibody therapy designed to bind to cancer cell antigens
This therapy prevents uncontrolled cell division by blocking chemicals from binding to cancer cells.
How do monoclonal antibodies prevent cancer cell growth?
By attaching to cancer cell antigens, preventing chemicals from binding
This mechanism disrupts the signaling pathways that promote cell division in cancer cells.
What is indirect monoclonal antibody therapy?
Monoclonal antibodies with drugs attached that target cancer cells
This method delivers cytotoxic drugs directly to cancer cells, minimizing side effects compared to traditional therapies.
What are ‘bullet drugs’?
Monoclonal antibodies with attached drugs that kill cancer cells
The term emphasizes the precision of these therapies in targeting cancer cells directly.
What is the role of a cytotoxic drug in cancer treatment?
To kill cancer cells directly
Cytotoxic drugs are often used in conjunction with monoclonal antibodies to enhance the effectiveness of treatment.
What can monoclonal antibodies be used to test for?
- Pregnancy
- Influenza
- Hepatitis
- Chlamydia
- Prostate cancer
Examples include the Covid 19 antibody test.
What does ELISA stand for?
Enzyme-linked immunosorbent assay
ELISA is a common laboratory technique used for detecting and quantifying substances.
What is the role of the first mobile antibody in an ELISA test?
It is complementary to the antigen being tested for and has a coloured dye attached.
This helps in visualizing the presence of the antigen.
What is the function of the second antibody in an ELISA test?
It is immobilised in the test and complementary in shape to the antigen.
This helps in capturing the antigen for detection.
What does the third antibody do in an ELISA test?
It is immobilised and is complementary in shape to the first antibody.
This further aids in the detection process.
Fill in the blank: The test for pregnancy involves detecting _______.
hCG
hCG stands for human chorionic gonadotropin, a hormone produced during pregnancy.
True or False: A clear blue line in a pregnancy test indicates that the individual is pregnant.
True
This is a common result interpretation in home pregnancy tests.
What is the first step in the ELISA test procedure?
Add the test sample from a patient to the base of the beaker
This initiates the testing process to detect the presence of an antigen.
What is done after adding the test sample in the ELISA test?
Wash to remove any unbound test sample
This step ensures that only the bound antigens remain for further testing.
What type of antibody is added after washing the test sample in the ELISA test?
An antibody complementary in shape to the antigen you are testing
This antibody specifically binds to the antigen present in the sample.
What must be done after adding the first antibody in the ELISA test?
Wash to remove any unbound antibody
This step is crucial to ensure the specificity of the test.
What is the function of the second antibody in the ELISA test?
Binds to the first antibody and has an enzyme attached to it
This enzyme will later react with a substrate to produce a color change.
What is added to the ELISA test after the second antibody?
The substrate for the enzyme, which is colourless
The substrate reacts in the presence of the enzyme to produce a colored product.
What does the presence of color in the ELISA test indicate?
The presence of the antigen in the test sample
The intensity of the color indicates the quantity of the antigen present.
What ethical issues arise from the creation of monoclonal antibodies?
Use of mice to produce antibodies and tumor cells
This raises debates about the justification of animal use for human benefit.
What type of cells are involved in the fusion process to create hybridomas?
Myeloma cells and spleen cells
This fusion is essential for producing monoclonal antibodies.
What is the purpose of culturing hybridomas in HAT medium?
Select for positive cells
HAT medium allows only the desired hybridoma cells to grow.
What is the final step in the process of creating monoclonal antibodies?
Harvest monoclonal antibodies
This provides the antibodies needed for various applications, including cancer treatment.
What is the core structure of HIV?
Genetic material (RNA) and reverse transcriptase
These components are essential for viral replication.
What does the capsid of HIV refer to?
Outer protein coat
The capsid protects the viral RNA and enzymes.
What is the function of the envelope in HIV?
Extra outer layer made of lipids from the host’s cell membrane
The envelope aids in the virus’s ability to infect host cells.
What role do protein attachments play in HIV?
Enable the virus to attach to the host’s helper T cell
This is crucial for the virus to initiate infection.
What is the primary target cell for HIV?
Helper T cells
HIV specifically targets these immune cells, which are vital for the immune response.
What happens when HIV attaches to a helper T cell?
The HIV protein capsule fuses with the helper T cell membrane
This fusion allows the virus’s RNA and enzymes to enter the host cell.
What is reverse transcriptase’s function in HIV?
Copies viral RNA into DNA
This process is essential for integrating viral material into the host’s genome.
What is the term for HIV due to its replication process?
Retrovirus
This classification is based on the reverse transcription of RNA to DNA.
What occurs after reverse transcription in the HIV life cycle?
Viral DNA integrates into the host DNA
This integration allows the virus to hijack the host’s cellular machinery.
How is a mature virion formed in HIV replication?
Viral protease cleaves new polyproteins
This process is necessary for the maturation of infectious virus particles.
What is the significance of new viral RNA in HIV?
Used as genomic RNA and to make viral proteins
This RNA is crucial for producing new viral particles.
Fill in the blank: HIV is transported around in the blood until it attaches to a _______.
CD4 protein
The attachment is a key step in the HIV infection process.
True or False: HIV can be destroyed by antibiotics.
False
Antibiotics are ineffective against viruses because they target bacterial cell walls.
