Chapter 11.1 Flashcards
What is special about all cells of organisms?
They all have unique molecules on their cell surface
What is special about the immune system?
The fact that it can distinguish between self and non-self cells
What will the immune system do when it recognizes a foreign body?
It will react with an immune response that will eliminate the intruder from the body
What surface molecules do all nucleated cells have? and are they recognized by the immune system?
They are known as self cells, also called major histocompatibility complex molecules that function as identification tag. Due to genetically determined markers, the immune system will not recognize them
What is a non-self (antigen) cell?
Any substance that is recognized as foreign and is capable of triggering an immune response
What is the immune response that is conducted when an antigen is detected?
Lymphocytes bind to the antigen as well as detect the exposed portion (epitope). Then will release antibodies which are able to bind to epitope via complementary paratope
What are some antigenic determinants?
-Surface markers found on foreign bodies
-The self markers of a different organism on the cell
-Proteins unless they are broken down into component parts
What is special about the surface of red blood cells?
Are not nucleated and hence do not possess the same distinctive and unique self markers as all other body cells. Red blood cells do possess basic antigenic markers which limit the capacity for transfusion
What may be found on the surface of the red blood cells?
Red blood cells may possess surface glycoproteins (A and B antigens) either independently (A or B) or in combination (AB). Alternatively, red blood cells may possess neither surface glycoprotein (denoted as O)
Is blood transfusion applicable to all blood groups?
No as humans produce antibodies for any foreign antigens. AB blood groups can receive blood from any other type. A blood groups cannot receive B blood or AB blood. B blood groups cannot receive A blood or AB blood. O blood groups can only receive transfusions from other O blood donor
What is a pathogen?
A agent that causes disease and could be a microorganism, virus or prion.
What is a disease?
Any condition that disturbs the normal functioning of the body
What is an illness
A deterioration in the normal state of health of an organism
What are examples of human specific diseases?
Polio, syphilis, measles and gonorrhoea
What is a special ability that pathogens possess?
They are able to cross the species barrier and infect other organisms
What is a special ability that pathogens possess?
They are able to cross the species barrier and infect other organisms
What are zoonotic diseases and what are examples of them?
Diseases from animals that can be transmitted to humans. Rabies (dogs), certain strains of influenza (e.g. bird flu) and the bubonic plague (rats)
What are the different mechanisms of disease transmission?
-Direct contact: the transfer of pathogens via physical association or the exchange of body fluids
-Contamination: ingestion of pathogens growing on, or in, edible food sources
-Airborne: certain pathogens can be transferred in the air via coughing and sneezing
-Vectors: intermediary organisms that transfer pathogens without developing disease symptoms themselves
What are the type of immune reactions that the immune system will undergo if faced by a foreign body?
The specific and non-specific immune response
What is the non-specific immune response?
Macrophages will engulf pathogen and break them down internally
What is the specific immune response?
When the non-specific macrophages will show antigenic fragments on surface of cells for specific
T lymphocytes
What is the role of T lymphocytes?
Release cytokines when antigenic fragments are presented to them
What is the role of the cytokine?
Stimulates the release of B cells that produce antibodies to the antigen and produce clones
How will the clones be divided?
The larger portion would form plasma cells that release antibodies, and the smaller portion will develop into long-lived memory cells which serve to produce a long term immunity
What is special about the plasma cells?
The fact that they are short-lived and release a large quantity of antibodies for specific antigen
How do antibodies aid in the destruction of pathogen?
Precipitation – Soluble pathogens become insoluble and precipitate
Agglutination – Cellular pathogens become clumped for easier removal
Neutralization – Antibodies may occlude pathogenic regions (e.g. exotoxins)
Inflammation – Antibodies may trigger an inflammatory response within the body
Complement activation – Complement proteins perforate membranes (cell lysis)
How do the action of antibodies aid the immune system?
Aiding the detection and removal of pathogens by the phagocytic leukocytes of the innate immune system
How would macrophages aid in helping the immune system?
Improve pathogen identification, as well as engulf pathogens more efficiently
What does immunity depend on?
The persistence of memory cells
Why is there a delay period between the first pathogen exposure and the production of antibodies?
Due to the reliance of immune system to undergo clonal expansion of plasma cells that produce a sufficient amount of antibodies
What prevents this delay period?
Memory cells
How do memory cells work?
If a second infection with the same pathogen occurs, memory cells will react more vigorously to produce antibodies faster. As antibodies are produced faster, the pathogen cannot reproduce in sufficient amounts to cause disease symptoms. Hence, because pathogen exposure no longer causes the disease to occur, the individual is said to be immune
What is an allergen?
An environmental substance that triggers an immune response despite not being intrinsically harmful
What is an allergic reaction?
The immune response which is localized at region of exposure
What does the allergic reaction require in order to work?
Prior exposure to the allergen which is a pre-sensitized state
How does the allergen get into a pre-sensitized state?
When a specific B cell first encounters the allergen, it differentiates into plasma cells and makes large quantities of IgE antibodies. The IgE antibodies attach to mast cells, effectively ‘priming’ them towards the allergen.
What happens upon re-exposure of allergen?
Upon re-exposure to the allergen, the IgE-primed mast cells release large amounts of histamine which causes inflammation
What does inflammation do?
Improves leukocytes mobility to infected regions by triggering vasodilation and increasing capillary permeability
What is vasodilation and what does it result in?
Vasodilation is the widening of blood vessels to improve the circulation of blood to targeted regions, causes redness and heat
What is capillary permeability and what does it result in?
Capillary permeability describes the capacity for leukocytes to leave the bloodstream and migrate into the body tissue, leads to swelling and pain
What is the goal of vaccinations?
Induce long-term immunity to specific pathogenic infections by stimulating the production of memory cells
What is a vaccine?
A weakened or attenuated form of the pathogen that contains antigens but is incapable of triggering disease
How can the immune response be boosted?
Antigenic determinants in a vaccine may be conjugated to an adjuvant
How does the body respond to the injection of a vaccine?
By initiating a primary immune response, which results in memory cells being made
What happens when body is confronted by pathogen after vaccine injection?
Memory cells trigger a more potent secondary immune response, due to potency symptoms will not develop
Why are vaccination programs implemented?
To reduce the outbreak of particular infectious diseases within populations
What is an epidemic?
Substantially increased occurrence of a particular infection within a given region
What is a pandemic?
An epidemic that has spread across a large geographical area
What is herd immunity?
When individuals who are not immune to a pathogen are protected from exposure by the large amounts of immune individuals within the community
What are monoclonal antibodies?
Antibodies artificially derived from a single B cell clone
How are monoclonal antibodies synthesized?
An animal is injected with an antigen and produces antigen-specific plasma cells. The plasma cells are removed and fused with tumor cells capable of endless divisions. The resulting hybridoma cell is capable of synthesizing large quantities of monoclonal antibody
How are monoclonal antibodies used?
Disease detection as well as therapeutic treatment
What is an example of therapeutic treatment of disease using monoclonal antibodies?
Treatment of rabies
How are rabies treated?
Injecting purified antibodies into individuals, target cancer cells that the body’s own immune cells fail to recognize as harmful
What is an example of diagnostic use of monoclonal antibodies?
Test for pregnancy via the presence of human chorionic gonadotrophin (hCG) in urine
What process do pregnancy tests use?
The enzyme linked immunosorbent assay to identify substance via color change
How does ELISA work?
Free monoclonal antibodies specific to hCG are conjugated to an enzyme that changes the color of a dye. A second set of monoclonal antibodies specific to hCG are immobilized to the dye substrate. If hCG is present in urine, it will interact with both sets of monoclonal antibody. When both sets of antibody are bound to hCG, the enzyme is brought into physical proximity with the dye, changing its color. A third set of monoclonal antibodies will bind any unattached enzyme-linked antibodies, functioning as a control
