Chapter 43 - The Immunity System Flashcards
what are the 3 lines of defense in the immune system? describe them
1.) physical barriers = block entry
=> (ex: skin, mucous membranes,
secretions)
2.) internal innate responses = rapid, broad specificity
=> (ex: inflammatory response,
phagocytic cells)
3.) adaptive immunity = slower, highly specific, develops through life
=> (ex: humoral response = antibodies
defend against infection in body fluids,
cell-mediated response = cytotoxic cells
defend against infection in body cells)
what barriers prevent pathogens from entering your body?
surface barriers
what are the 3 main surface barriers?
skin, mucous membranes, and commensal bacteria (mutual, we need them)
what are the 6 types of leukocytes (white blood cells)?
neutrophils
eosinophils
basophils
macrophages
dendritic cells
lymphocytes
neutrophils
phagocytosis (ingest or engulf foreign/unwanted/bacteria cells)
eosinophils
low phagocytic activity
fights large parasites
basophils
secrete inflammatory chemicals
(ex: mast cells)
macrophages
large phagocytes
(ex: monocytes)
dendritic cells
alerts the adaptive immune system
tells lymphocytes (B and T cells) that there is an antigen present
lymphocytes
a type of white blood cell (leukocyte) that is mainly found in the lymphatic system (lymph fluid)
true or false: innate immune responses rapidly target pathogens after binding ligands
true
what are innate immune responses?
first line of defense against invading pathogens
fast-acting response to bacteria and viruses
what are the 2 innate immune responses? describe them
cell-mediated
=> phagocytosis = neutrophils and
macrophages
=> targeted death of infected host cells
= natural killer (NK) cells (lymphocytes)
non-cellular
=> complement proteins = membrane
attach complexes (ones that help)
=> anti-microbial peptides
anti-microbial peptides
these are part of the non-cellular innate immune response
they inhibit cell division by inhibiting DNA replication and DNA damage response, blocks the cell cycle causing failure of chromosome separation
histamine
increases blood flow (vasodilation), makes capillaries more “leaky”
cytokines (in relation to inflammatory response)
signaling proteins that attract/activate other immune cells
what is the adaptive immune response mediated by?
they are mediated by lymphocytes with highly specific cell surface (antigen) receptors
what is adaptive immunity?
slow-reacting and develops through life (when the immune system responds to a foreign substance)
(ex: bacteria enters the body, the body deals with it, and remembers how to deal with it
what are the 2 types of adaptive immunity? describe them
1.) humoral response = antibodies defend against infection in body fluids
=> B-cells
2.) cell-mediated response = cytotoxic cells defend against infection in body cells
=> T-cells
what are the 3 types of lymphocytes?
B-cells, T-cells, and natural killer (NK) cells
B-cells
mature in bone marrow, antibody (humoral) mediated response
how many binding sites are there in a B-cell?
2 binding sites
T-cells
mature in thymus, cell-mediated response
how many binding sites are there in a T-cell?
1 binding site
how many polypeptides are in a cell surface receptor
4 polypeptides
antigen
any molecule that elicits a response from B or T cells
epitope
the portion of an antigen that binds the antigen receptor (looks like a puzzle piece)
the antigen receptor shakes hands with the epitope
there are several epitopes per antigen
random DNA recombination
generates receptor diversity
what is the process of random DNA recombination?
1.) recombination deletes DNA between randomly selected V segment and J segment
2.) transcription of permanently rearranged functional genes occurs
3.) RNA processing
4.) translation
self-tolerance
your lymphocytes (B and T cells) are programmed to recognize your own cells so that they don’t kill your own cells
lymphocytes tolerate your own cells
the body lacks lymphocytes (white blood cells in the lymphatic system) that can react against its own components
lymphatic system
the tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases
(ex: bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels)
auto-immune disease
immune system attacks itself (“self-intolerance”)
true or false: lymphocytes with matching receptors are selected and clonally expanded
true
what are the 3 steps of clonal selection? describe them
1.) selection = the antigen binds onto the antigen receptor on a B-cell
2.) replication/expansion (mitosis) = the “selected” B-cell gets replicated
3.) differentiation = differentiate into effector cells and memory cells
effector cells
B-cells that act immediately when a pathogen enters the body
immediate action short-lived
memory cells
persist for subsequent exposure (future infections)
what are the main aspects of an antigen receptor?
recognize epitopes on antigens
unique to each cell (due to cell recombination)
highly specific
what are the 3 ways antibodies dispose of antigens?
1.) neutralization
2.) opsonization
3.) complement proteins
opsonization
facilitate phagocytosis
the antibody binds to the antigen and signals the macrophage to come eat it
complement proteins
a group of proteins in the plasma that are part of the innate immune system (assists in antigen disposal)
what are the steps for allergy response? describe them
pollen allergy example
pollen allergy example
1.) initial exposure = during an allergic reaction immunoglobin E (IgE) released from B-cells will bind to mast cells
2.) subsequent exposure = the allergen (in this case it is pollen) binds onto the IgE
3.) cross-linking (process of chemically joining two or more molecules by a covalent bond) triggers the release of histamine
=> its an overreaction basically
cross-linking (pertaining to allergy response)
the process of chemically joining two or more molecules by a covalent bond
=> (ex: Ige + pollen joining)
lysis
disintegration of a cell by rupture of the cell wall or membrane
what do cytotoxic T-cells (Tc) need to activate?
CD8 protein that recognizes the MHC-1 molecule
T-cell receptor (TCR) that recognizes antigen
what 2 chemicals do activated T-cells release to kill infected host cells? describe the function of the 2 chemicals
1.) perforins = make pores
2.) granzymes = induce cell suicide (apoptosis)
what is the accessory protein, CD8, and receptor for cytotoxic T-cells?
accessory protein = CD8
activator = infected somatic cell
receptor = MHC-1
what is the activator and receptor for helper T-cells?
activator = antigen-presenting cell
(ex: dendritic cell, mast cell, etc.)
receptor = MHC-2
passive immunity
antibodies being “delivered” directly
(ex: breastfeeding, anti-venins/antivenom, etc.)
active immunity
defenses derived from response to infection (memory cells)
what uses active immunity?
vaccinations
vaccination
treatment with a vaccine to produce immunity to a particular infectious disease or pathogen
what are the 2 different vaccine molecules?
1.) live attenuated (weakened virus)
2.) dead/inactive (dead virus)
how does HIV escape adaptive immunity?
antigenic variation and latency (dormancy)
antigenic variation
changes in epitope expression
bacteria/virus alters the proteins/carbohydrates on its surface and avoids the host cell’s immune response
latency (dormancy)
the long asymptomatic period between initial infection and development
it hides out in the host genome
acquired immunodeficiency syndrome (AIDs)
the comprised immune system resulting from helper T-cell reduction
helper T-cell: (–)
HIV concentration: (+)
relative anti-HIV antibodies concentration: (–)
CRISPR (clustered regular interspersed short palindromic repeats)
prokaryotic adaptive immune system
it edits genes by precisely cutting DNA
trypanosome
parasitic worm-like creature
has glycoproteins all over the surface of their body that are encoded by a gene that is duplicated more than a thousand times in an organism’s genome
each copy is slightly different and it can change glycoproteins on its surface area
