Outcome 13 - Immune System Flashcards
What is immunity?
body defending against damage or disease
What are the two categories of immunity?
- innate immunity
- adaptive immunity
what are external barriers that make up the first lines of defence?
- physical: skin, mucous membrane, hair/cilia, saliva, urine
- chemical: sebum, lysozome, gastric juice, vaginal secretion
What are the internal barriers that make up the second line of defence?
- antimicrobial substances
- natural killer cells
- phagocytes
- inflammation
- fever
What type of lymphocyte is part of the second line of defense?
phagocytes - neutrophils, macrophages, dendritic cells
NK cells
what are the 5 steps of phagocytosis?
- chemotaxis
- adherence
- ingestion
- digestion
- killing
what does PRISH stand for?
Pain
Redness
Immobility
Swelling
Heat
what is the first step of inflammation?
vasodilation, and increase blood vessel permeability
what is the second step of inflammation?
emigration of phagocytes
what phagocytic cell usually travels first to site of infection?
neutrophils
what is the precursor cell of a macrophage?
monocytes (in blood)
macro - in tissue
how does a fever function as a line of defence?
in attempt to inhibit microbe growth and to increase metabolic activity to aid in repair and to increase the effect of interferons
what are the two characteristics of adaptive immunity?
- specific for a particular foreign molecule (antigen)
- acquires memory for previously encountered antigens (making the second response faster)
what types of lymphocytes are involved in adaptive immunity?
t and b cells
what is the stem cell that lymphocytes are derived from?
multipotent stem cells from red bone marrow
where do lymphocytes mature?
B cells mature in the RBM
T cells mature in the thymus
what type of lymphocyte is responsible for cell-mediated immune response?
cytotoxic T cells (CD8 T cells)
what type of lymphocyte is responsible for antibody-mediated immune response?
B cells
what are the two types of T cells?
cytotoxic T cells (CD8 T cells + helper T cells (CD4 T cells)
memory T cells in lymphatic tissue
what type of adaptive immunity is effective against INTRACELLULAR pathogens?
cell-mediated immunity
what type of adaptive immunity is effective against EXTRACELLULAR pathogens?
antibody-mediated immunity
It is common for an antigen to provoke both the cell-mediated and antibody-mediated immune responses. t/f
true
Upon first encounter with an antigen, there is a large group of lymphocytes that have the correct antigen receptor. t/f
false
only a small group does
What is clonal selection?
creation of more t and B cells that have the correct antigen receptors
what are the two major categories of cells produced during clonal selection?
- effector cells
- memory cells
what is an antigen?
substance that is foreign and provokes an immune response
ANTIbody GENerator
what part of the antigen provokes an immune response?
the epitope
what are our self-antigens?
MHC antigens (multi-histocompatibility complex)
which type of lymphocyte leaves lymph tissue in the case of antigenic invasion?
cytotoxic t effector cells
what type of lymphocyte needs the antigen to be presented to them for activation?
T cells
what is the importance of t helper cells?
secrete cytokine (local hormone) that helps the activation and speed up the clonal selection process
what type of cells secrete antibodies?
B cells
what class of antibody is the most abundant?
IgG
what class of antibody can cross the placenta and be transferred to the fetus?
IgG
what class of antibody can be transferred to the fetus via breast milk?
IgA
list 5 different actions that antibodies use to disable the antigen.
- neutralize antigen
- immobilize bacteria
- agglutination (clumping)
- activate complement
- enhance phagocytosis
how are primary and secondary immune responses related to the rationale for immunization?
idea is to introduce your body to antigens to produce antibodies (primary)
then if you actually get exposed to that pathogen with those antigens again, your response will be faster bc you already had memory cells with those antigen receptors (secondary)
what is the different between active and passive immunity?
active - when your body is exposed to the pathogen so your body produces its own antibodies
passive - when antibodies are given to you
what are the primary lymphatic organs?
where immune cells are produced and matured
- red bone marrow + thymus
what are the secondary lymphatic organs?
where most immune responses occur; where most lymphocytes are housed
- lymph nodes/vessels + spleen (white pulp)
what is innate immunity?
- non-specific resistance
- present at birth
- immediate protection against a wide variety of invaders
what is adaptive immunity?
- specific resistance that is developed in response to particular invaders - exposure to specific antigens
- not present at birth
adaptive immunity is faster than innate immunity. t/f
false
what are some substances that contribute to inflammation?
- histamine, kinins, prostaglandins, leukotrienes, + complement system
what is leukocytosis?
high WBC in serum
what is pus?
the accumulation of dead phagocytes and damaged tissue
what is immunocompetence?
the ability of the lymphocytes to carry out adaptive immune responses
how does a cell become immunocompetent?
they need to have specific antigen receptors embedded into their cell membranes
which type of cells carry out immune response during a primary response?
effector cells
which type of cells don’t participate in the initial immune response?
memory cells
what type of cells die off after the immune response is finished?
effector cells
what type of cells do not die at the end of an immune response?
memory cells
what are the 2 important characteristics of antigens?
- immunogenicity
- reactivity
what is immunogenicity?
the ability to produce immune response
antibody production or T cell activation
what is reactivity?
ability to react SPECIFICALLY with antibodies or cells it provoked
describe epitopes.
-part of the antigen molecules that trigger the immune response
-antigenic determinants
- what attaches to the t and b antigen receptors
what can happen if an antigen gets past nonspecific resistance and enters the blood? interstitial space? mucous membranes?
- blood —> get trapped in the spleen
- interstitial space by lymph —> get trapped in lymph nodes
- travel along mucous membranes —> encounter MALT (mucosa-associated lymphatic tissues)
regardless of the route that the antigens take (when past the nonspecific resistance), where do they end up?
in the lymphatic tissues where lymphocytes are found
what gives B cells and T cells its unique set of genes to code for unique antigen receptors?
genetic recombination
where are mhc antigens found?
all our nucleic cells
what is hapten?
small molecule that has reactivity but not immunogenicity (therefore, not a complete antigen)
can hapten stimulate immune responses?
yes. if they attach to large carrier molecules
what is responsible for some allergic reactions to drugs and environmental substances?
hapten.
what results in an autoimmune disorder?
when the body can’t distinguish “self” from “non-self”
B cells recognize and bind to what kind of antigens?
exogenous antigens (which are fluids outside of body cells)
what is endogenous antigen presentation?
infected body cells that process and present antigens on their cell membrane
what is exogenous antigen presentation?
insertion of fragments of the exogenous antigen onto their cell membrane
- travel to lymphatic tissue to present it to t cells
what is cell-mediated immunity?
- T cell with correct antigen receptor binds to specific antigen presented to them by an APC or infected body cell
where do you find cytotoxic t effector cells?
secondary lymphatic tissues
what do cytotoxic t effector cells do?
bind to infected cells and cause apoptosis or cytolysis by enzymes, perforin and granules
when does antibody mediated immunity happen?
when correct antigen receptor binds to a specific antigen
during antibody-mediated immunity what undergoes clonal selection?
plasma cells and memory b cells
why is B cell activation even more intense than T cell activations?
B cells bind directly to an antigen where T cells need the antigen presented to them
what are plasma cells?
B cells that become effector cells
what do plasma cells do?
they secrete antibodies
describe antibody structures.
they match the B cell receptors that initially bound to the specific antigen
what do antibodies + antigens form?
antigen-antibody complex
what are antibodies also called?
immunoglobulins
what are the 5 classes of immunoglobulins?
- IgG
- IgA
- IgM
- IgD
- IgE
which class of Ig is found in lymph?
IgM
which class of Ig is the first to be secreted by plasma cells?
IgM
which class of Ig also presents as monomers on surfaces of B cells?
IgM and IgD
which class of Ig is involved in allergic and hypersensitivity reactions and protection against parasitic worms?
IgE
which class of Ig is involved in allergic and hypersensitivity reactions and protection against parasitic worms?
IgE
what is monoclonal antibody production?
the isolation of one type of antibody (MAb)
what do you call the combination of cancer/tumour cells and wanted antibodies?
hybridoma
what do they use MAb for in NM?
“radio”immunotherapy - theranostics (diagnostics and therapy)
- attaching radiation to monoclonal antibodies that will bind to specific tumour cells
what is more effective? primary or secondary response?
secondary response - more effective for IgG production due to memory cells that already exist
what are 4 ways to acquire adaptive immunity?
- NATURALLY acquired ACTIVE immunity
- NATURALLY acquired PASSIVE immunity
- ARTIFICIALLY acquired ACTIVE immunity
- ARTIFICIALLY acquired PASSIVE immunity
what is the difference between active and passive immunity that is acquired naturally?
active - getting it from the environment (creation of t and B cells by encountering the real virus)
passive - getting antibodies from mom to fetus by placenta or breast milk but it doesn’t last forever like memory cells
what is the difference between active and passive immunity that is artificially?
active - vaccination - introduction of weakened/dead pathogen that leads to production of antibodies leading to memory cells
passive - injection of antibodies
