Vaccines Flashcards
What are examples of physical barriers in our bodies immune system?
- Skin prevents bacteria from entering
- Acids in stomach that kills bacteria that enters
- Lungs have mucus layers and cilia that removes bacteria
What is an example of an extracellular pathogen?
Poison, venom
Why do certain dyes only work for some bacteria?
A specific dye may only connect to a certain protein or glycan
Dye can be used to bind to infectious agents as a treatment, but using too much _________ the effect
diminishes
What are oligopeptides?
Peptides that are short (contain only 4-5 amino acids)
Lymph nodes checks extracellular fluids for infectious agents and if they find any, they trigger an ______ ______
immune response
Macrophages and neutrophils are white blood cells that _______ other cells
engulf
When antibodies bind to antigens, _______ occurs, and this allows the virus to be cleared out of the body
clumping
COVID-19 can cause immune surge/burst, in which…
the immune response is so strong that it kills the host, as regulatory T cells are not stopping it.
What is immunology?
The science that studies immune systems
What immune system is a network of ______, cells, and molecules that protect the body from foreign invaders
organs
What was the first observation that evolved into immunity?
Some individuals did not get sick while others around them did
What observation led to the idea ofvaccines?
Individuals who were exposed to a disease and survived would later be “immune” if exposed again to that disease
What did the first attempts of vaccination consist of?
A small or weakened dose of a harmful substance
What are 3 early examples of immunuty?
- In Poland, small exposure to arsenic can stimulate the liver to produce enzymes which inactivate its effects
- Snake handlers become immune to venom after multiple bites
- People who had small pox gained protection against future small pox - Acquired Immunity!
Why did the WHO declare small pox eradicated?
Due to use of the smallpox vaccine
What was the unethical experiment that kick started small pox vaccines?
Edward Jenner collected cowpox material and inoculated a child with it. They developed a fever, but was now immune from smallpox
Describe Louis Pasteur’s work with making a chicken cholera vaccine
- He obtained cultures of the bacteria
- He wanted to inoculate chickens with it, but he and his assistant were both on vacation
- He decided to inject aged bacteria anyways
Results:
Chicks with old bacteria did not get sick
Chicks with fresh bacteria did get sick
Chicks with fresh bacteria, but had been injected with old beforehand, did not get sick
What are the 3 layers of defences in the immune system?
Physical barriers
Innate immune system
Adaptive immune system
The ______ immune system provides immediate, non-specific responses when pathogens breach physical barriers
innate
The ______ immune system is activated by the response of the _______ immune system.
adaptive, innate
The adaptive immune system ________ pathogens and remembers them
recognises
What are some major functions of the innate immune system?
- Recruit immune cells to infection sites with chemical factors
- Identify bacteria, active cells, and promote clearance of debris
- Activate the adaptive immune system through antigen presentation
- Serve as a physical and chemical barrier to pathogens, like sap in tree and clotting in blood
What 2 types of immunity contribute to both innate and adaptive immunity?
Humoral immunity
Cell-mediated immunity
What is humoral immunity?
The aspect of immunity facilitated by macro molecules found in extracellular fluids. This includes antibodies and some antimicrobial peptides
What is cell-mediated immunity
The activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, macrophages, and various cytokines in response to antigens
What is the side-chain theory of immune response?
White blood cells produce side chains that bind to antigens. These chains break off to become antibodies that specifically target toxins and pathogens without harming the body
In the 1880’s, scientists discovered that _____ _____ cells gather at inflammation sites and could engulf and destroy bacteria. Later, researchers shows that bacteria released _________ that attract these leukocytes
white blood, oligopeptides
________ are involved in both the innate and adaptive immune response
leukocytes
What are 4 types of white blood cells?
- Macrophages
- Neutrophils
- T Cells
- B Cells
What are 2 categories of white blood cells based on their functional characterstics?
- Phagocytic: part of the innate immune system and removes foreign particles
- Adaptive: Involves antibodies and antigens
___________ and ______ are part of the immune system’s first line of defence as part of the innate immune response
macrophages, neutrophils
Wound healing involves the _______ immune response
innate
How does wound healing work?
- Injured cells release signal like cytokines and other chemicals
- These signals recruit phagocytic white blood cells to infection site
- These white blood cells destroy invading pathogens through consumption or releasing chemicals
The adaptive immune response initiates after a first exposure to a ________, and then protects from re-infection and disease upon subsequent exposures
pathogen
In the adaptive immune system, pathogens are remembered by a unique antigen by _______ cells
memory
_ cells mature in the bone marrow and _ cells mature in the thymus
B, T
_ cells are involved in cell-mediated immunity and _ cells produce antibodies and antigens
T, B
What are antibodies and antigens? How do they interact?
Antibodies: protective proteins produced by the immune system to identify and kill pathogens
Antigen: Unique molecule on the surface of foreign objects
Specific antibodies (Y shaped) bind to specific antigens in a lock-key pattern.
After binding, the pathogen is removed, primed for phagocytosis, or cannot do anymore harm as they can no longer bind
How do B cells contribute to humoral immunity?
- Secrete antibodies
- Act is antigen-presenting cells (APCs) by secreting antigens and cytokines
- Express B cell receptors (BCRs) which allow B cells to bind to specific antigens, against which it will initiate an antibody response
How do T cells contribute to cell-mediated adaptive immune responses?
- Distinguished by T-cell receptor (TCR)
- Matures into several distinct types of T cells that is specific for a particular antigen
- Activates into effector T cells once a specific antigen is encountered
Where and how to B cells mature?
In the bone marrow, but in the Fabricius for birds
Where and how to T cells mature?
Migrate from marrow to thymus gland, where they mature into several types or removed.
They get distinct TCR by genetic recombination and splicing. TCR consists of alpha and beta chains
They are removed if they can’t bind to MHC-2 to if they react to self proteins. Only 2% survive
What are Effector T cells?
A group of t-cells that includes several T cell types that actively respond to a stimulus
What are 3 types of Effector T cells and what do they do?
Regulatory T Cells (Treg) - Stop T cell-mediated immune response at the end of an immune reaction. Also suppresses auto-reactive T cells that escaped the process of negative selection in the thymus
T Helper Cells (Th cells) - Help other leukocytes in immunologic processes, including maturation of B cells into plasma and memory B cells
Cytotoxic T cells - Destroy virus infected cells and tumour cells
B cells turn into plasma cells and memory B cells. What do they do?
Plasma Cells: Produce antibodies to trigger immune response
Memory B Cells: Remain inactive until a second encounter with the antigen. They then divide to form more plasma cells
When do B cells divide into plasma and memory B cells?
After maturation, B cells migrate to secondary lymphoid organs where they are exposed to antigens.
BCRs bind to specific antigens and divide with the help of T cells
Describe the process of B cell activation and proliferation
- Antigen is engulfed by B cell after being matched
- Antigen epitope sent to cell surface and binds to MHC-2 proteins
- Helper T cells bind to the MHC-2 proteins on the B cell
- Helper T cells are activated, releasing cytokines that induce B cell proliferation
- B cells become either plasma or memory B cells
What is an epitope?
Part of the antigen that is recognised by the immune system
How does the adaptive immune system all work together?
- Helper T cells activate B cells and cytotoxic T cells once presented with antigens on MHC-2 molecules
- Activated B cells produce antibodies that bind to antigens and prevent infection
- Cytotoxic T cells bind to bad cells and kill them
