Lecture 1&2 Intro and cells of immune system Flashcards
colonize body surfaces but do not invade the body and dont normally cause disease
commensals
organism that can cause disease
pathogen
cause disease every time it invades body, even in small numbers such as HIV
primary pathogen
cause disease only when administered in high doses
opportunistic pathogen
why is it better/why do multiple mechanisms work together to ensure microbial destruction
bacteria grow fast meaning more chances of mutation/adaptation
having multiple mechanisms allow for something to always be available to defend
what are the two branches of the immune system
innate immunity
adaptive immunity
characteristics of innate immunity
1.immediate protection (first line of defense)
2.always there, can’t change..has to act fast
3.not specific only worried if something is foreign or not
4.activated by PAMPs and DAMPs
5.provides important signals for adaptive immune response
- efficient
- can work independently of adaptive immunity but enhanced by adaptive immunity
characteristics of adaptive immunity
- cells dont recognize pathogen as a whole; VERY SPECIFIC
2.develops days to weeks after exposure - memory
- tolerance (prevents us from attacking our own cells)
- enhance innate immune response
components of innate immunity
1.physical/chemical barriers
2.phagocytic and sentinel cells
3.complement system
4.innate defense cytokines
5. natural kill (NK) cells
components of adaptive immunity (2 types of adaptive immunity)
1.humoral immunity (antibodies)
2.cell-mediated immunity ( T-helper, cytotoxic T cells, and gamma delta T cells)
what makes up the innate defense physical/chemical barriers
epithelial barriers (skin, mucus membrane)
normal microflora
acid environment in stomach
antimicrobial peptides
these ingest and kill pathogens
phagocytic cells
examples of phagocytic cells
neutrophils
macrophages
resident tissue cells that detect invasion by recognizing PAMPs and DAMPs
sentinel cells
examples of sentinel cells
dendritic cells (DC)
macrophages
mast cells
what does PAMPs stand for
pathogen-associated molecular patterns
**tells innate immune system that something is foriegn)
what does DAMPs stand for
damage-associated molecular patterns
**turns of the immune response
what is the complement system
an rapidly induced enzyme cascade system that has antimicrobial activity
series of 20-30 proteins in blood plasma
multiple mechanisms for controlling infection
protein messenger molecule that can act on other cells or the cell that produced it
tells what response is needed based on the pathogen noticed by the sentinel cells
cytokines
secreted by sentinel cells in response to PAMPs and DAMPS
cause fever, lethargy, and loss of appetite
proinflammatory cytokines
examples of pro-inflammatory cytokines
IL-1
IL-6
TNF
these cause cells to migrate to sites of infection, some produced by sentinel cells
chemokines
interferes with replication of viruses; produced by virally infected cells
interferons
What are NK cells
also called natural killer cells (type of lymphocyte)
- part of innate defense
- looking for the absence of normal (missing receptor, etc.)
- kill virus infected cells and tumor cells
- recognize and kill cells that DO NOT express normal proteins
humoral immunity is mediated by ________
antibodies
named so because transfer of body ‘humors’ from protected animal to naïve animal could provide protection
__ cells or ___ lymphocytes produce antibodies
B,B
what are the types of antibodies
IgM
IgG
IgA
IgE
named so because transfer of cells from protected animal to naïve animal could provide protection
cell-mediated immunity
another word for antibody
immunoglobulin (Ig)
what are the two classes of T cells based on T cell receptors
Alpha Beta T cells
examples of alpha beta T cells:T helper cells and
Cytotoxic T cells
Gamma delta T cells
any type of white blood cell (WBC)
leukocyte
a type of WBC (T cell, B cell, and NK cell)
lymphocyte
what are some examples of granulocyte/ polymorphonuclear cells
neutrophils
eosinophils
basophils
define granulocyte/polymorphonuclear
present granules
multi-lobular nucleus
if cells are phagocytic they are referred to as
monoocytes
if cells are NOT phagocytic they are referred to as
lymphocytes
these cells are important for clotting
platelets
approximate percentage of eosinophils in blood and half-lives
1-3% of WBCs in circulation
30 minutes in blood stream then go to tissues and are mostly found under epithelial surfaces; they live a couple of week in the tissues then replaced by new cells
approximate percentage of basophils in blood and half-lives
0.5% of WBCs in circulation
1-2 days
approximate percentage of monocyte in blood and half-lives
3-7% of WBCs in circulation
circulate 1-2 days then migrate to tissue and differentiate into a macrophage (guard cell)
approximate percentage of neutrophils in blood and half-lives
55-90% of WBCs in circulation
8 to 10 hours
approximate percentage of lymphocyte in blood and half-lives
20-35% of WBCs in circulation
120 days; circulate for about 4 months between blood and lymphoid tissues searching for antigens they recognize
* if they dont find their match (antigen) they die*
do basophils contain granules
yes, that stain basophilic filled with inflammatory mediators
examples: histamine, serotonin
do eosinophil contain granules
yes which stain eosinophilic filled with potent mediators capable of killing parasites
basophils are important in ________ and ________ infections (secondary to eosinophils)
allergy
parasitic
eosinophils are important in control of ________________
extracellular parasites
**eosinophilia can occur with some parasites and allergies
macrophages are found in most tissues and are extremely important in immune responses:
list 3 responses
phagocytosis and killing bacteria
presentation of antigen on MHC 2
secretion of cytokines
monocytes/macrophages arrive at the site of infection __________ neutrophils. Their accumulation at the site of inflammation is a sign of __________________
after
chronic infection
_____________ spends a lot of energy making neutrophils
bone marrow
why does bone marrow spend a lot of energy making neutrophils
easier to just kill off something rapidly which is what neutrophils do compared to other lymphocytes
roles of neutrophils
- first responders (arrive within 4hrs)
- exit blood stream at the site of infection and accumulate in large numbers to ingest and kill pathogens
- attack and destroy (suicide bombers) pathogens especially bacteria and fungi and die in the process
bone marrow increases production of neutrophils in response to bacteria infection resulting in a left shift known as _____________
neutrophilia (elevated neutrophil count in blood)
neutrophilia is commonly seen in animals with a _________ infection
bacterial
dead neutrophils result in the formation of _________
pus
lower than normal numbers of neutrophils in the blood stream
neutropenia
neutropenia is seen in animals with a __________ infection
viral
what is unique characteristic of lymphocytes compared to other WBCs
other WBCs once they exit the blood they stay in the tissues
lymphocytes are able to bounce between blood and tissues
B-cells and T-cells are part of ____________ immunity
adaptive
If lymphocytes (B,T, and NK cells) meet their antigen, what happens?
they get activated and some differentiate into memory cells
what is the importance of endothelial cells that line the blood and lymph vessels
important for regulating leukocytic (WBC) traffic
have addressins that allow circulating WBCs to know where the are in the body (flags)
what are addressins
adhesion molecules in endothelial cells that stick a flag in the spot in the body to tell WBCs where they are at
what happens to addressins when infection is present
they are upregulated to facilitate binding of neutrophils to the endothelial cells and their subsequent exit to the site of infection
all immune cells originate from _______________
bone marrow
what are the three lineages of immune cells
erythroid
myeloid
lymphoid
what are examples of erythroid
RBC
platelets
what are examples of myeloid
monocytes
neutrophils
eosinophils
basophils
some dendritic cells (important in initiation of immune response)
mast cells
what are examples of lymphoid
B cells
T cells
NK cells
some dendritic cells
____________are released in a mature state
granulocytes
___________ cells migrate to tissues and mature. These are important __________ and ___________. Key in initiation of adaptive immunity.
dendritic
sentinel cells and antigen presenting cells
______________ precursors leave bone marrow and mature in tissues. Live from weeks to months and are important in parasitic infection and allergies
mast cells
__________________ are released immature from the bone marrow as ________ which go to the thymus to mature
T lymphocytes
pre-T cells
in the _________, a T-cell receptor is generated by DNA arrangments
thymus
T/F each T-cell has a specific cognitive antigen
TRUE
T/F if the newly generated receptor recognizes antigen in thymus, it is eliminated
TRUE
T/F if the newly generated receptor recognizes MGC molecule but not antigen, then the T cell matures and goes to secondary lymphoid tissue
TRUE
____________ are released immature from the bone marrow as pre- ____cells, which mature in primary lymphoid tissue
B lymphocytes
B
T cells are to the thymus, as B cells are to
primates, rabbits, rodents: bone marrow
birds: bursa of Fabricius
Ruminants, pigs, dogs: Peyer’s patch
NK cells are released _____________ from the bone marrow
Immature or mature
mature; ready to function
T/F NK cells are antigen specific
false
just B and T cells
Do NK cells have memory
NO
they are apart of the innate immunity
Differentiation in secondary lymphoid organ occurs when a _______, ___________ B or T cell meets its __________
mature, naïve
antigen
B cells differentiate into effector ________________ that secrete antibody, or ____________ which are long lived clones of the cell
plasma cells
memory cells
T cells in response to their antigen, differentiate into _________ or _____________
memory or effector cells
distribution of lymphocytes in the body:
highest % location
lowest % location
40% lymph nodes
2% blood
primary lymphoid organs
bone marrow
Peyer’s patch
Bursa
Thymus
____________ of lymphocytes takes place in primary lymphoid tissues-lymphocytes from bone marrow travel to these tissues to mature
maturation
large number of lymphocytes are located in the _____________ waiting to encounter their antigen
this tissue increases chances of a lymphocyte meeting its antigen
secondary lymphoid tissue
lymphocyte rich tissue connected to lymphatic system, where adaptive immunity response to lymph-borne antigen is initiated
lymph nodes
site for adaptive immune response to blood borne antigens
spleen
where adaptive immune response to antigens invading from the mucosal surfaces is initiated
MALT (mucosal associated lymphoid tissue)
