SAC for unit 1 specifically Flashcards
What are antigens
molecules or parts of a molecule that stimulate immune response through the adaptive immune response.
antibodies definition
proteins produced by plasma cells in response to antigens and which react specifically with the antigen that induced their formation
immunoglobulins definition
They are another term for antibodies
inflammation definition
an innate reaction by the immune response to foreign particles or injury resulting in redness and swelling
what is a vector
an agent or vehicle used to transfer pathogens or genes between cells and organisms
Cytotoxic T cell definition
T cells that are activated by cytokines to bind to antigen–MHC-I complexes on infected host cells and kill infected body cells
what are the 2 ways antigens can be classified as
self or non-self
self antigens are:
those that are not foreign and are thus usually tolerated by the immune system
non-self antigens definition
Non-self antigens can be identified as invaders and can be attacked by the immune system.
what is the main way for an immune cell to tell self and non-self antigens apart
the cell surface receptors that tell them if they are self or non-self (MHC)
what is the major histocompatibility complex
receptor proteins on the surface of cells that identify the cells as ‘self’
where are MHC-l markers found
all nucleated cells
what do MHC-l markers do
provide a site for binding of antigens to occur, that allows cells to be recognised as ‘self’ so they will not be attacked
Where are MHC-II markers found
- mainly on specific white blood cells, including antigen-presenting cells (macrophages and dendritic cells)
- and helper T cells.
what do MHC-ll markers do
the antigen presenting cells present antigens on their surface on these MHC-II markers, which bind to helper T cells to help activate the adaptive immune response.
what is a pathogen
A pathogen or infectious agent is a biological agent that causes disease or illness to its host
what are the 2 types of pathogens
- cellular
- and non-cellular
what are the 4 main cellular pathogens
- bacteria
- parasites
- fungi
- protozoa
what are protozoans (cell info)
single-celled eukaryotic cells
what are bacteria (cell info)
They are singular chromosome and double stranded DNA, prokaryotic cells
cellular pathogens definition
any disease-causing agent made up of cells that can reproduce independently without relying on the host machinery
what type of cell are cellular pathogens
can be both eukaryotes or prokaryotes
what is a major reason why bacteria is a pathogen (what do they produce)
toxins
what does it mean when said fungi are opportunistic pathogens
when it has the chance, bacteria can become a pathogen externally or internally
what do bacteria toxins do
damage particular tissues of their host organism and cause disease
main difference between eukaryotic and prokaryotic cells
eukaryotic cells have a distinct nucleus containing the cell’s genetic material, while prokaryotic cells don’t have a nucleus and have free-floating genetic material instead
what are the 2 main non-cellular pathogens
- viruses
- prions
virus definition
non-cellular pathogens that use the host cell in order to replicate their genetic material
prions definition
infectious particles made of protein that lack nucleic acids (folded proteins)
how can viruses travel to other organisms
Virions are the means by which a virus can transfer from one host cell to another
what do all viruses have (structure)
- genetic material, either DNA or RNA, organised as a single molecule or as several molecules
- a protein shell, known as a capsid, that surrounds the genetic material.
what is lysis
destruction of cells by rupturing the membrane of the cell
how do viruses spread (release particles from cell)
The mode of release of viral particles from an infected cell may be by budding or by cell lysis.
what do prions do
triggers normal proteins in the brain to fold into an abnormal structure
what is an incubation period
the time period between infection and the first appearance of the symptoms of a disease
what pathogen has a long incubation period
prions
what is an allergen
an antigen that elicits an allergic response
what systems do allergic response involve
cells from both the innate and adaptive system
innate immunity definition
the type of immunity that is present from birth, is fast acting but not long lasting, and produces non-specific (generic) responses against classes of pathogens
adaptive immunity definition
an immune response that is specific to a particular antigen and develops through contact with an antigen
immunological memory definition
ability of the adaptive immune response to remember antigens after primary exposure
what are the 2 types of actions that the immune system uses to protect against infection
- cell-mediated immunity
- humoral immunity
cell-mediated immunity definition
immune response that is mediated by immune cells
humoral immunity definition
immune response mediated by soluble molecules in the blood, lymph and interstitial fluid that disable pathogens
what kinds of cells are all cells in the immune system
white blood cells
lymphocytes definition
class of white blood cells found in all tissues including blood, lymph nodes and spleen, and which play a role in specific immunity
B cells (B lymphocytes) definition
white blood cells that recognise antigens or pathogens and produce a large number of antibodies specific to an antigen
T cells (T lymphocytes) definition
white blood cells that mature in the thymus and participate in the adaptive immune response
what happens in the lymph nodes
B cells and T cells are activated and adaptive immune responses occur
what is apart of the 1st line of defense
a physical, chemical and microbiological barriers to prevent pathogens from gaining entry to the body
what is apart of the 2nd line of defense
the actions of immune cells and soluble proteins mounting a rapid but non-specific attack against pathogens that gain entry to the body.
what is apart of the 3rd line of defense
the recognition of specific antigens by lymphocytes
what type of immunity do the 1st and 2nd line of defense use
innate immunity
what type of immunity does the 3rd line of defense use
adaptive immunity
physical barriers definition
innate barriers that act to prevent the entry of pathogens into the body
what is 1 example of a physical barrier in plants
stomata (close to prevent pathogen entry)
what is 1 example of a physical barrier in animals
intact skin
What are the 3 barriers that prevent the entry of pathogens into an organism (1st line)
- physical barriers
- chemical barriers
- microbiological (microbiota) barriers
chemical barriers definition
a innate barriers that use enzymes to kill pathogens and prevent invasion into a host
what is 1 example of a chemical barrier in animals
sweat (with lysozyme)
what is 1 example of a chemical barrier in plants
caffeine (Toxic to fungi and insects)
microbiological barriers definition
innate barriers involving normal flora in the body
how to chemical barriers (sweat and tears) kill pathogens
by an enzyme called lysozyme that kills the pathogens
when does the second and third line of defense start to work
when pathogens have entered the body (cut in skin)
phagocytosis definition
bulk movement of solid material into cells where the cell engulfs a particle to form a phagosome
what are the 3 key aspects of innate immunity
- soluble proteins
- inflammation
- immune cells
what are the 6 main white blood cells (immune cells)
- natural killer cells (NK cells),
- mast cells,
- eosinophils
- macrophages
- neutrophils
- dendritic cells
what are two other names for immune cells
white blood cells
leukocytes
which of the 6 immune cells are phagocytes
- neutrophils
- dendritic cells
- macrophages
where are neutrophils, eosinophils and NK cells found
in the bloodstream
what are the 2 granulocytes
eosinophils, neutrophils
what are granulocytes
a type of white blood cell that has small granules inside their cytoplasm
which immune cells are antigen presenting
- dendritic cells
- macrophages
simple overview of steps in phagocytosis
- pathogen recognised by pattern recognition receptor
- pathogen engulfed by phagosome
- Lysosomes fuse with the phagosome
- pathogen is destroyed by toxic chemicals and lysosome
- material is discharged by exocytosis
In these antigen presenting cells what is on their surface (specifically MHC-ll markers) once phagocytosis happens
some antigens or sub-units from the digested pathogen on the MHC-ll markers (activating adaptive immune system)
macrophage info (brief)
they identify eliminate and engulf pathogens by phagocytosis and clear dead cells and debris. Also antigen presenting (can activate adaptive immune response)
Neutrophils info (brief)
Neutrophils are abundant immune cells that are usually the first to the site of an infection, engulfing and destroying pathogens.
dendritic cells info (brief)
Dendritic cells are professional antigen-presenting cells, engulfing pathogens and presenting their antigens to T cells to activate the adaptive immune response.
eosinophils info (brief)
assist in defending against larger parasitic agents that are too large to be engulfed by phagocytosis. They contain granules with toxic chemicals and histamine
NK cells info (brief)
lymphocytes that kill virus-infected cells through apoptosis
degranulation info for NK cells
There granules contain granzymes and perforin. The perforin makes holes in the cells plasma membrane allowing the granzymes to enter. This enzymes induces apoptosis
degranulation definition
the process by which immune cells release various chemicals (such as histamine and antimicrobials) stored within secretory vesicles known as granules
mast cells info (brief)
they are vital in the inflammatory response. As well as releasing histamines that increase vascular permeability, they also release cytokines that attract other immune cells to help destroy the pathogen. (out of granules) (also contain heparin)
histamine definition
a substance involved in inflammation and allergic reactions that causes blood vessels to dilate and become more permeable to immune cells
what is the cell-mediated immunity for the second line of defense
the immune cells attacking the pathogen
what is the humoral immunity for the second line of defense
complement proteins and cytokines
what are complement proteins
proteins that assist other innate immune cells and can destroy bacterial cells by lysis
what are cytokines
signalling molecules of the immune system
what is an important cytokine in the innate immune system and definition
interferons,
proteins secreted by some cells, in response to a virus infection, that helps uninfected cells resist infection by that virus
where are complement proteins found
dissolved in blood plasma
what are the 3 things that complement proteins do
- opsonising pathogens
- recruiting immune cells involved in an inflammatory response (chemotaxis)
- destroying bacterial pathogens by lysis
opsonisation definition
the coating of the surface of pathogen cells by complement proteins, making the pathogens more susceptible to phagocytosis
Why does opsonisation make pathogens more susceptible to phagocytosis
phagocytes have receptors for complement proteins on their plasma membranes, and these bind to the opsonised microbes. Allowing for direct binding to the pathogen
what is chemotaxis
movement of a cell or organism in response to a chemical substance
how does chemotaxis work for complement proteins
Small complement peptides that diffuse from the pathogen surface act as chemical signals, attracting immune cells involved in the inflammatory response
how do infereons work
Once a body cell is infected with viruses, the cell secretes interferons. That cell is doomed, but the interferons that it secretes into its surroundings act as warning signals to nearby cells so that they can prepare in advance for a possible virus infection
what is the membrane attack complex (MAC)
one of the defence mechanisms resulting from activation of complement proteins that destroys pathogen cells by osmotic shock
how does lysis work with complement proteins
complement proteins interact with pathogens allowing for the MAC to form on there plasma membrane. Lysis then occurs
how does lysis work
The MAC inserts into the plasma membrane of the pathogen and produces a pore that allows fluid to enter, causing the pathogen cell to swell and burst — explosive death by osmotic shock
how are complement proteins activated (cascade attached)
The activation of a complement protein occurs when the protein is cut (cleaved) into two fragments — a larger activated protein and a smaller peptide fragment. This sequence of reactions starts a cascade that can neither be stopped nor reversed.
Or C3 makes direct contact with molecules on the surface of a pathogen
are complement proteins inactive enzymes?
yes
process involved in complement activation (2 steps)
- The activation of an initial complement protein (known as C3) starts a sequence of reactions that take place on the surface of a pathogen. The first protein in the series enzymatically alters the next protein in the series.
- The product of the first reaction then activates the next enzyme in the series, which, in turn, activates the next protein, and so on.
what are the 5 main symptoms of inflammation
- redness
- pain
- heat
- swelling
- pus
what are the 4 functions of the lymphatic system
- production and maturation of immune cells
- the removal of excess fluids from body tissues
- absorption and transportation of fatty acids to the digestive system
- allowing for the process of antigen recognition by T and B lymphocytes
what 4 things does the lymphatic system have in it (structure)
- lymph
- lymphatic vessels
- primary lymphoid organs
- secondary lymphoid organs
what are the primary lymphoid organs
bone marrow and thymus
what are the secondary lymphoid organs
lymph nodes and spleen
what happens in the bone marrow
- source of pluripotent stem cells (where immune cells originate)
- and site of maturation of B cells
what is lymph
is the fluid in the lymphatic system that gets squeezed out of blood vessels
what happens in the thymus
site where T cells mature after being released from the bone marrow
3
what happens in the spleen
- filters the blood passing through it, clearing the blood of bacteria and viruses as well as worn-out red blood cells
- contains T cells and B cells that detect and respond to infectious agents in the blood
- contains other immune cells
what are lymph nodes
Lymph nodes are the sites in which antigen recognition occurs
what is antigen recognition
This is where antigen-presenting cells display their antigens to their specific T and B lymphocytes, leading to expansion of the appropriate lymphocytes for adaptive immunity
what do the helper T cells cytokines do to other cells
These can initiate either the humoral adaptive immune system (through stimulating the clonal selection and clonal expansion of B cells) or the cell-mediated immune system (through stimulating the clonal selection and expansion of cytotoxic T cells).
6 steps involved with antigen presenting and initiation of immune response (adaptive immune response)
- pathogen is engulfed by APCs
- pathogen is degraded into fragments (my fusion with lysosome)
- some of the fragments are presented on MHC-II markers
- They present these fragments to helper T cells by moving to the lymph nodes (antigen presentation)
- Helper T cell binds to the antigen (via receptors) and activates the helper cell
- Helper T cells release cytokines (interleukins) that activate B or T cells
where does antigen presentation happen
lymph nodes
what are the 3 functions of helper T cells
- activate cytotoxic T cells
- activate B cells into becoming antibody-producing plasma cells
- activate macrophages to remove - antibody-coated pathogens by phagocytosis
what is the two main features of the adaptive immune response
- specificity
- Immunological memory
what is specificity (adaptive response)
the ability to recognise and respond to specific antigens
3 key components of adaptive immune response
- T cells and B cells
- antibodies, also known as immunoglobulins
- lymph nodes, organs where B cells and T cells meet foreign antigens and are activated
what are the 2 types of B cells
- B plasma cells
- B memory cells
what is the humoral immune response for the adaptive response
Involves the actions of antibodies that identify and bind to extracellular pathogens, to toxins and to other extracellular foreign antigens. Antibodies are products of special B plasma cells.
where do B cells develop
bone marrow
what is the cell-mediated immune response for the adaptive response
involves various actions of T cells. Cytotoxic T cells eliminate body cells that are infected by pathogens or have abnormal or missing self markers. They eliminate intracellular pathogens.
where do T cells develop
thymus
what are the 5 steps of activation of humoral response
- After the helper T cell activates the interleukins they naive B cells are activated
- The B cells undergo clonal expansion to produce clones of B cells
- These clones differentiate into plamsa B cells or memory B cells
- plasma B cells secrete antibodies to the antigen, memory B cells remain in the lymphoid tissue
- then PIANO occurs via antibodies
what are naive B and T cells
B and T cells that haven’t been activated
what is precipitation (antibodies)
they bind to soluble antigens, making them insoluble, causing them to precipitate out of the solution, creating a solid (more visible)
what is in clonal selection
when the correct naive B or T cell binds to the antigen
what is in clonal expansion
when the naive B or T cell differentiates
what are the chains of an antibody
light and heavy chains (light short, heavy long)
what are the 2 regions of an antibody
- variable region (ends that bind to antigens)
- constant region (most of the antibody)
what is acronym to remember what antibodies can do to pathogens and what does it stand for
PIANO
precipitation
inflammation
agglutination
neutralisation
opsonisation
what is agglutination (antibodies)
they bind to the surface antigens on pathogens to form antigen–antibody complexes, causing them to clump together (more visible)
inflammation (antibodies)
they release histamine, triggering inflammation
what is neutralisation (antibodies)
they bind to surface antigens on pathogens and form a coating that neutralises pathogens by blocking their receptors so that the pathogens cannot attach to healthy body cells and infect them
what is opsonisation (antibodies)
they bind to the surface antigens on pathogens to form antigen–antibody complexes and tag the pathogen for destruction. This activates phagocytes and complement proteins
cell-mediated adaptive response definition
a specific response in which cytotoxic T cells destroy virus-infected cells using perforin and granzyme B
how do cytotoxic T cells recognise and bind to infected cells
the MHC-I marker
what happens in the 4 steps of activating the cell-mediated adaptive response
- After the helper T cells release interleukins it will activate naive T cells
- They then undergo clonal expansion to produce these T cell clones
- These clones differetiate into cytotoxic T cells and memory T cells
- The cytotoxic T cells release perforin and granzyme B, destroying the infected cell via it intiating apoptosis
how do cytotoxic T cells do apoptosis
- release perforin, making a hole in the cell
- secrete granules (granzyme B) enter the cell and initiate apoptosis
what are the two ways we can gain immunity depending on the source of the antibody
- actively (active immunity)
- passively (passive immunity)
what happens in active immunity
antibodies are produced by a person’s own adaptive immune system
why and how does natural immunity occur
occurs naturally, without deliberate intervention
what are the two means of gaining immunity
- naturally
- artificially
how does artificial immunity occur
is induced through a deliberate intervention
what is natural active immunity
a type of immunity in which the body produces antibodies in response to a normal infection by a pathogen
what does artificial active immunity involve
the deliberate and artificial introduction of a disabled pathogen or its toxin to the body (vaccination)
what happens in passive immunity
antibodies are acquired by a person from an external source
what is natural passive immunity
a form of immunity in which an individual receives antibodies from a natural source, such as through breastfeeding
what is artificial passive immunity
the injection of antibodies, providing immediate response, (antivenom)
disease definition
a condition in a living animal or plant body that impairs the normal functioning of an organ, part, structure or system
what are the 2 types of diseases
- non-infectious
- infectious
what are emerging diseases
a disease caused by a newly identified or previously unknown agent
what is re-emerging disease
reappearance of a known disease after a significant decline in incidence
what are pandemics
a situation when, over a relatively short time, many people worldwide contract a specific disease as it spreads from a region of origin
what are epidemics
the widespread occurrence of an infectious disease in a community or in a restricted geographic area at a particular time
impacts of european settlement on aboriginals
- brought disease foreign to them, causing lots of spread (death)
- such as smallpox
what can we identify to quickly stop the spread of the disease
the host or the pathgoen
what are the 2 modes of transmission
- direct transmission
- indirect transmission
what is direct transmission
mechanism of transmission of pathogenic agents that involves direct person-to-person contact, such as by kissing or sexual contact
what is indirect transmission
mechanism of transmission of pathogenic agents that does not involve direct person-to-person contact, such as by airborne droplets or by ingestion of contaminated food
what are asymptomatic carriers
a person with an infectious disease showing no symptoms but able to infect others
what is the R0 value?
the basic reproduction number that identifies the expected number of individuals a person with a certain disease will infect
what are the 6 methods of disease control
- prevention
- vaccination
- medication
- surveillance
- modification of environment
- infection control standards
example of modification of environment
spraying chemicals to eliminate breeding of the pathogens
example of infection control standards
washing hands
what are antibiotics
a class of antimicrobial drug used in the treatment and prevention of bacterial infections that act either by killing pathogenic bacteria or by inhibiting their growth
what are vaccination programs
mandated programs that set a schedule in which vaccinations against specific diseases should be administered
what is herd immunity
indirect protection, at the population level, against an infectious disease; the protection is created by the presence in the population of a high proportion of individuals who are vaccinated against the particular disease
what are the 3 ethical approaches
- consequences-based
- duties or rules-based
- virtues-based
what is the consequence based approach
this approach places important on the consideration of the consequences of an action, with the aim to get the most positive outcomes and least negative ones
what is the rules/duties-based approach
places importance on the idea that people have duty to act in a particular way (follow the rules)
what is the virtues-based approach
consideration is given to the virtue or moral character of the person carrying out the action (did they try to do the right thing)
what are the 5 ethical concepts
- integrity
- non-maleficence
- justice
- beneficence
- respect
what is integrity
commitment for searching for knowledge and understanding that they have to share all their results
what is justice
moral obligation to ensure that there is fair consideration of all competing claims; no unfair burden on specific group
what is beneficence
maximising benefits and minimising risks
what is non-maleficence
involves avoiding the causations of harm
what is respect
consideration that all living things have intrinsic value (need to consider everything, animals, plants, etc.)
what are 2 ways to identify pathogens
- ELISA
- microscope
elisa definition
a technique known as enzyme linked immunosorbent assay, which can detect specific antigens or antibodies
what are monoclonal antibodies
specifically designed antibodies used in the treatment of some diseases such as cancer and autoimmune disease
how are mAbs made
- a mouse is injected with antigens, allowing for their B cells to produce and antibody which is withdrawn (from spleen)
- then they are fused with collected tumor cells in suspension
- they make hybrid cells (hybridomas)
- these cells are isolated to grow separately
- they then grow many of these mAbs
what can mAbs be used for
- treat cancer
- treat autoimmune disease
what are the types (forms) mAbs can be in
- naked
- conjugated
what is a naked mAbs
mAbs that dont have any molecules attached
what is a conjugated mAbs
mAbs that have other molecules attached
what are the 4 modes that mAbs can be used to treat cancer
- stop growth of blood vessels
- signal immune attack
- block growth factors
- deliver anticancer or radioisotopes to the cancer cells
what 3 things can naked mAbs do to treat cancer
- block signalling to prevent growth by inhibiting blood vessels (bind to growth factor)
- they block signals for cell division (cant replicate cancer cells)
- they can bind to tumor cells to signal attack from immune system
what does conjugated mAbs do to treat cancer
they bring the anticancer and radioisotopes to the cancer cells (kill the cells)
what is autoimmune disease
a disease where antibodies attack self cells
how can mAbs be used to help treat autoimmune disease
alter the course of an autoimmune disease by directing the antibodies against major histocompatibility antigens to prevent them triggering an autoimmune response
