immunology Flashcards
is the immune system big - explain
enormous
scattered throughout the body
connected by blood and lymph
not localized, very diffuse
describe the immune systems role in protection
protects whole body at all times
must reach all parts of body at the same time
what does immune system protect against
pathogens - bacteria, viruses, parasites
altered body cells - cancer
what happen when immune system turns on us
autoimmune disorders - own immune system sees you as foreign
foreign tissues: transplant or graft - immunosuppressant stops rejection
name the 2 prongs of immune system
non specific/innate immunity
specific/adaptive immunity
born with both
describe briefly innate/nonspecific immunity
first line of defence
does not need to recognize pathogen - nonspecific
same response each time it sees a pathogen
describe briefly specific/adaptive immunity
requires recognition of the pathogen
faster response when it sees the same pathogen again
describe the 3 mains way things are discovered in science
accidents of nature - like a stroke - reveals that stroke effects speech
leaps of faith - make observation and test
serendipity - happy accidents
name and describe something that was discovered by serendipity
Penicillin
fungus on plates
no other bacteria can grow there - discovered first antibiotic
name and describe something that was discovered by accidents of nature
SCID
lack of formation of immune system
david vetter
missing a specific cytokine important for different immune cells
injected with bone marrow from sister - but she had mononucleosis (epstein barr virus) and david died
describe aids (discovery)
80s in young men
HIV kills T helper cells
which are important in adaptive immune response
name and describe something that was discovered by leap of faith
smallpox vaccination
1796 - edward jenner
saw milkmaids had pox on hands but dont get small pox
they contracted cow pox
took puss of pox and injected into son and he did well
this caught on and people were doing this - saves lives
describe smallpox
dreadful infectious disease- killed over 300 million people and lasted for 3000 years and killed 30% of those who had it
is small pox still an issue
no
last man who had it in world = 1977 ali maow maalin - survived with treatment
2 other cases = accidental lab exposure - 1978 - one died
Eradicated in 1980
why is immunization called vaccination
Because smallpox virus = vaccinia virus - vaccine comes from cow pox
what are the 3 main components of immune system
lymphoid organs
immune cells - leukocytes
Secretions of immune cells - cytokines
describe types of lymphoid organs
primary lymphoid organs - sites where stem cells divide and immune cells develop
secondary lymphoid organs - sites where most immune responses occur
name types of sites of primary lymphoid organs
bone marrow (yolk sac and fetal liver in embryo)
thymus
describe bone marrow (primary lymphoid organs)
fetal liver in embryo - site of hematopoiesis
blood cells produced here - B cells and immature T cells
site where B cells mature
describe thymus (primary lymphoid organs)
located above heart
contains T cells, scattered dendritic cells, epithelial cells and macrophages
site where T cells mature
atrophies after maturity (small in old people)
name the 3 secondary lymphoid organs
lymph nodes - main site
spleen
lymphoid nodules
describe lymph nodes (secondary lymphoid organs)
scattered in body ~ 600 of them
biggest ` 1cm in size
filter microbes - filters and traps
macrophages in nodes phagocytize microbes that enter lymph
site where immune reponse occurs - carry back and fight in lymph nodes
describe spleen (secondary lymphoid organs)
largest lymphoid organ
removes microbes and old erythrocytes
describe lymphoid nodules (secondary lymphoid organs)
tonsils & adenoids at back of throat - help protect respiratory tract
peyers patches (in gut) and MALT (mucosal associated lymphoid tissues - at every place that contacts external environment)
appendix - part of SI
where do immune cells travel
blood and lymphatic vessels
what are immune cells
Leukocytes
white blood cells
why are they called B cells
remove bursa of chicken = no more b cells
describe the 2 lineages of wbcs
lymphoid or myeloid
what does lymphoid committed stem cell give rise to
lymphocytes =
T cells (cytotoxic T cells CD8+, helper T cells CD4
+, regulatory T cells CD4+)
B cells
NK cells
what does myeloid committed stem cell give rise to - form immune system
neutrophil
monocyte –> macrophage and dendritic cells
eosinophil
basophil
why are granulocytes important
release different components
like histamines - increase blood flow and allergic response
cytokines
effectors
which cells are granulocytes
esoinophils
basophils
mast cells
describe eosinophils
destroys parasites
describe basophils
release a variety of chemicals, histamine, prostaglandins
describe mast cells
release chemicals
histamines
describe neutrophils
phagocytes
first important one at site of infection
describe monocytes
become macrophages and dendritic cells (phagocytes)
when is immune system activated
when breach in barrier - at level of skin
allows pathogens to get into tissue
starts with nonspecific branch - things like inflammation
describe the nonspecific/innate immunity branch
ability of body to defend against microbes and other foreign substances without recognition of pathogen
first line of defence - physical barriers
second line of defence - cellular factors and humoral factors
define first line of defence and name the 3 components
barriers to skin and creating an unpleasant environment for microorganisms
Additional physical and mechanical barriers
Chemical and microbiological barriers
describe skin (first line of defence)
water resistant
prevents entry of foreign substances
describe additional physical and mechanical barriers
(first line of defence)
tight junctions in epithelia - like in gut
mucus
hair and cilia - lungs so move out stuff and wont be infected
describe chemical and microbiological barriers (first line of defence)
secretions - sebum, lysozyme, gastric juice
normal flora - microbiological components - help fight bacteria and infection
describe second line of defence - innate immunity
no memory - humoral factors
inflammation and fever
Antimicrobial substances - acute phase reactants (happen quick)= c reactive protein (produced by liver in response to inflammation), complement, cytokines
interferons
mobilize wbcs to site of infection to help fight off
what is inflammation
non specific response to tissue damage
what are 4 distinct signs and symptoms of inflammation
redness
heat
pain
swelling
what are 3 stages of inflammation
vasodilation
emigration of phagocytes
tissue repair
describe vasodilation (inflammation)
Widening of blood vessels allow more blood to flow to site
increased permeability of capillaries allows substances to go to damaged site
stretch of capillary and endothelial cells allows more fluid to move into tissues
what are humoral substances
Discourage microbial growth or spread of pathogen
name the 3 humoral substances
interferons
complement
iron binding proteins
describe interferons (humoral substances)
antiviral proteins
what does type 1 interferon prevent
viral replication
describe how type 1 interferon prevents viral replication
usually - viruses come in and use DNA to replicate then cells die and virus particles go on to infect other cells
cell detects virus and secretes interferons
these have receptors and when activated causes cell to produce antiviral proteins - these prevent virsu from using cell to replicate
describe complement (humoral substances)
large family of plasma proteins with multiple functions
30 different proteins participate in the immune cascades
describe pathway of innate immunity for complement
pathogen surfaces –> complement activation (C3b) –> opsonization of pathogens = bind to surface of bacteria and prepare for eating
describe function of complement C3b as an opsonin
C3b receptor
C3b sticks to bacteria and makes it easier for phagocytes to recognize foreign cell and ingest bacteria
describe iron binding proteins (humoral substances)
transferrin
very important for bacterial infection
non specific response will sequester iron and want to keep it away from infection - makes it harder for bacteria to divide since it wont have enough iron
what does bacteria in blood lead to
sepsis
so bacteria must travel in immune system
what does opsonization mean
prepare for eating
describe how a monocyte becomes a macrophage or dendritic cell
moves out into tissues = macrophage
or
dendritic cells (called dendritic because fingerlike projections look like drendrites on neuronal cells)
what else does second line of defence include
cellular factors - Natural killer (NK) cells (lymphocytes) and phagocytes (neutrophils)
describe NK cells
class of lymphocytes - similar to cytotoxic t cells
target virus infected cells and cancer cells
attack and kill targets directly after binding tom them
not antigen specific - does not to recognize
describe how NK cells work
cells do not express MHC class 1
release chemicals that lead to death of infected or abnormal body cells
releases perforin - forms pores in cells and then granzymes go in to cell and destroy it
describe relationship between MHC class 1 and NK cells
MHC 1 proteins expressed on all normal nucleated body cells
recognized by NK cells and they will not kill it
altered or absent MHC1 proteins do not stimulate a negative signal
NK cell is activated and releases agents that kill the cell
what do phagocytes do
non specifically engulf microbial invaders
name 3 types of phagocytes
fixed tissue macrophages - already in tissues
neutrophils - will be recruited to site of injury
monocytes - macrophages and dendritic cells
name 4 steps of phagocytosis and intracellular destruction of a microbe
adherence
ingestion
digestion
killing
describe phagocytosis and intracellular destruction of a microbe
recognition from endosome & brings in bacteria in membrane bound compartment (endocytosis and phagosome formation) –> combines with lysosome (low pH destroys bacteria) –> forms phagolysosome –> release of end products into or out of cells –> debris and signals
how do phagocytes recognize microbes
Detects unique conserved structures that are essential to microbial physiology (molecular signature of infection)
bacteria has cell wall proteins that mammals do not have
called PAMPS (pathogen associated molecular patterns)
what are PAMPS
cell wall components that can be recognized - body doesnt express
lipopolysaccharide (LPS) of gram negative bacteria
peptidoglycan
(PGN) of gram positive bacteria
what are PAMPS recognized by
immune system receptors = pattern recognition receptors (PRR), including toll like receptors on the surface of the macrophage
what are toll like receptors
Family of highly conserved transmembrane receptors essential for microbial recognition via PAMPs
nonspecific event
name the 2 domains for TLRs (toll like receptors)
extracellular domain for recognition of pathogens
intracellular signalling domain
name things recognized by toll like receptors
lipoproteins
Peptidoglycans
dsDNA
flagellin
lipopolysaccharides
what starts process of inflammation
Signalling starting with toll like receptors
describe the starting process of inflammation
fixed tissue macrophages in tissues have TLRs on surface and they recognize bacteria (PAMPS) and sends signal
cytokines start inflammation process - neutrophils come first
signalling event starts inflammation
describe emigration of phagocytes (steps of inflammation) - informally
phagocytes go to capillary spaces
neutrophils move out and leave capillary to site of infection and pick up bacteria
name 3 processes of emigration of phagocytes (steps of inflammation)
chemotaxis
margination
diapedesis
describe chemotaxis (emigration of phagocytes)
chemically stimulated movement of phagocytes
chemokines/chemoattractants - attract phagocytes (neutrophils)
describe margination (emigration of phagocytes)
sticking to endothelial cell
neutrophils will adhere and stick
describe diapedesis (emigration of phagocytes)
phagocytes move across capillary wall
finger like projections between pores of endothelial cells and moves into tissue
describe specific role of neutrophils in inflammation
neutrophils die in process of killing bacteria
NETs- neutrophil extracellular traps are made of processed chromatin and bound to granular and selected cytoplasmic proteins which come from lysed neutrophils
leads to production of pus - mixture of dead bacteria and neutrophils
describe APCs (antigen presenting cells) - informally
more macrophages and dendritic cells - move to site of injury
take to lymph node and activate immune system
phagocytize some bacteria and bring back to lymph node and spleen to activate immune response
what are antigens aka
immunogen - material that induces an immune response
allergen - if inducing an allergic response
ligand - for activating system
what does antigen stand for
ANTIbody GENerator
antibodies bind to antigen
what can antigens be
whole cell or part of a cell
non microbial = pollen, egg whites, incompatible blood cells, transplanted tissues
what is epitope
part of antigen recognized by immune cell and part that binds to antibody
what bridges gap between innate and adaptive immunity
dendritic cells - via antigen presentation by phagocytes
happens at lymph nodes
dendritic cell brings it back lymph node (region where other immune cells are)
describe specific/adaptive immunity
mediated by antibodies or cells
humoral antibody mediated immunity and cell mediated immunity
what is MHC
major histocompatibility complex (MHC)
name the 2 classes of MHC
MHC-1 (HLA-A, HLA-B, HLA-C)
MHC-2 (HLA-DP,HLA-DQ, HLA-DR)
only twins can have the MHCs on their cells
Signature of self - no one else would have the same - very hard for transplants
where is MHC-1 found
on all nucleated cells
where is MHC-2 found
on all APCs (macrophages, dendritic cells, B cells)
when do T cell receptors recognize antigens
only when they are associated with MHC-2 proteins (on surface)
part of antigen presentation process
what do APCs present
present exogenous antigens with MHC-II
on surface of phagocyte
describe steps of APC
ingest antigen
digestion into peptide fragments
synthesize and package MHC-II molecules
bind peptide fragments to MHC-II
insert antigen-MHC-II complexes on plasma membrane
name and describe the 2 antigen characteristics of adaptive immunity (acquired, specific)
reactivity = antibody binds specifically to antigen that provoked it
immunogenicity - can provoke an immune response by producing antibody to that antigen
which cells are APCs
MHC-II + antigen
interdigitating dendritic cell/ professional APC (carry antigen to regional lymph node and start process)
macrophage
B lymphocyte (cell)
define specific/adaptive immunity
ability of body to defend against specific microbes and foreign substances
involves memory for previously encountered antigens
which cells involved with adaptive/specific immunity
B and T cells
must recognize specific foreign material to be attacked
what is an antigen
any molecule that can trigger an adaptive immune response against itself of the cell bearing it
name 3 stages of typical adaptive immune response
recognition of an antigen by lymphocytes
lymphocyte activation
attack launched by the activated lymphocytes and their secretions (cytotoxic t cells - kill directly or plasma cells - secrete antibodies)
describe humoral cells - specific/adaptive immunity
B cells
transform into plasma cells and produce and secrete antibodies
use antibodies and complement to kill
describe cell mediated cells - specific/adaptive immunity
cytotoxic t cells kill infected cells
attack infected body cells, cancer cells, foreign cells
describe origins of B cells and T cells
lymphoid stem cell –> immature T and B cells
T cells = go to thymus to mature
B cells - go to secondary lymphoid organs, needs activation by antigen
cells from T cells (cytotoxic cells) kill cells - must recognize antigen first
also have memory cells
B and T cells must recognize antigen
T helper cell needed to fully activate T and B cells
describe process though lymph node
mature cells move into lymph bode
APC must find B and T cell to start process - it finds them
APC recognizes antigens
antigen recognized by specific receptors
expressed in T cells to have recognition
coreception required (B7-CD28 along with MHC-II
+ peptide -TCR)
what is checkpoint inhibition
all biological processes need shut off controls
immune response involves displacement of CD28 from B7 by CTLA4 or PD-1
describe checkpoint inhibition
T cell is binding to APC it will express MHC1 on surface - matches APC but eventually it will present new receptor (CTLA4 or PD-1 (similar)) and this is signal to turn off - no more t cells killing
in some cases = produce antibodies that are specific for CTLA4 or PD1 = will bind and prevent from being inactivated so T cells can keep killing - used in cancer therapy to kill cancerous cells
describe a situation on an APC
MHC-1 on APC
activates T helper cells
B cell will only be activated if it recognizes antigen
and either directly or via cytokines will be activated by helper T cell
describe humoral antibody mediated immunity (specific/adaptive immunity)
involves B cells (lymphocytes)
transform into plasma cells
synthesize and secrete antibodies
memory B cells - to respond faster
recognize pathogen
describe cell mediated immunity (specific/adaptive immunity)
involves cytotoxic T cells - similar to NK cells
kills infected body cells, cancer cells, foreign cells
what do macrophages do (to T helper cells)
at level of their endosome they can put together their own MHC class 2 molecule again with part of peptide (fragment of antigen) and carry it to regional lymph node
encounters T helper cells that have appropriate receptor on their surface
what does APC-MHCII-ANTIGEN complex do when it moves to regional lymph node
activates T helper, cytotoxic T cells and B cells –> all these cells produce memory cells
B cells also need to be activated by interaction of with antigen but needs cytokines form T helper cells to fully activate (to produce plasma cells that secrete antibodies)
name the 3 steps of activate T helper cells
1 - specific recognition (MHC2 +peptide-T cell receptor)
2 - co reception (CD28-B7)
cytokine release from APC (stimulates T helper cell)
what type of cells are T helper cells and what does that mean
CD4+ cells
there is also some recognition event between APC and T helper cell with respect to CD4
do B cells have to directly interact with APC
no
can B cells act as APCS - explain
yes they can
they can process and present antigen to T helper cell
can take in some of pathogen and break out and present on surface via MHC class 2 and with help of CD$ molecule will activate T helper cell
describe serum protein electrophoresis during infection and during normal
normal - super high peak in albumin, lower alpha 1, higher alpha 2, higher beta, low gamma globulin
infection - super high peak in albumin, lower alpha 1, higher alpha 2, higher beta, high peak gamma globulins (antibodies)
describe plasma cells - EM and other factors
cytoplasm completely filled with membranous structures = ER (endoplasmic reticulum)
need this bc cells are essentially protein factors
only job = produce antibodies ~thousands/min
short life span ~ one week
define antibodies
part of a group of proteins called globulins
immunoglobulins (Ig)
what do antibodies contain
two identical heavy chains
two identical light chains
what are regions of antibodies
variable region - variable heavy and light chain
constant region - handle at bottom
describe variable region of antibodies
antigen binding site
FAB region
antigen binding fragment
hypervariable region
describe constant region of antibodies
same in all antibodies of a class
Fc region
crystallizable fragment
what is purpose of hypervariable region of variable region of antibodies
hyper variable regions must be different to recognize different antigens and give antibody specificity
what is antibody class determined by
constant region, Fc
protein makeup
name the 5 classes of antibodies
IgG
IgA
IgM
IgD
IgE
describe structure of antibodies
Y shaped
globular
describe IgGs
most numerous
cross the placenta (pass from mom to fetus)
small size
2 binding sites = divalent
peak in electrophoresis
describe IgAs
found in MALT (mucosal associated tissues - anything in contact with outside world like lungs) and breast milk (passed from mom to nursing child)
4 binding sites = tetravalent
harder to move through body
dimer
describe IgMs
first formed
complement activation (opens complement cascade)
decavalent
pentamer
harder to move through body
describe IgDs
prenatal
describe IgEs
allergy
what is antibody mediated immunity carried out by
B cells
describe how antibody mediated immunity is carried out
B cells become activated in spleen, lymphoid nodule or lymph node, (secondary lymphoid organ) in presence of microbe
undergo clonal selection (have right receptor and clone of B cell will be selected to produce more of them) to produce = plasma cells and memory cells
what do memory cells allow
faster response if antigen is seen again
name the 2 types of antibody immunity
actively or passively acquired
describe actively acquired antibody immunity
the persons own immune system responds to microbe
long lasting protection - memory cells involved
natural or artificial
describe passively acquired antibody immunity
person receives antibodies from another person or animal
temporary protection - no memory cells involved
natural or artificial
describe types of actively acquired antibody immunity
natural = develops when person is exposed to an antigen by chance (ex=flu)
artificial = develops when person is purposefully exposed to antigen (ex=flu vaccine)
describe types of passively acquired antibody immunity
natural = IgG from mother to fetus across placenta & IgA in breast milk
artificial = receive serum containing antibodies from person or animal that has been vaccinated (ex=ebola/covid)
define active immunity
resistance due to bodys contact with microorganism, their toxins or other antigenic components (from infection or vaccine)
what type of thing is active immunity
vaccine = may consist of small quantities of living or dead pathogens, small quantities of toxins or harmless antigenic molecules derived from microorganism or its toxin
does not cause disease but response (parts of immune response)
describe general principle of active immunity
exposure to antigenic substance results in active immune response that induces formation of memory cells required for rapid, effective response to future infections by that particular organism (more robust)
define passive immunity
direct transfer of antibodies from one person to another
describe 2 examples of passive immunity
fetus receives maternal IgG antibodies that cross placenta
breast fed children receive IgA antibodies in moms milk (intestinal mucosa is permeable to IgA antibodies during early life - short, will get diluted out or used in system)
what is important for infant during first months of life and why
passive immunity - sources of protection
antibody synthesizing capacity is relatively poor
name the 6 antibody functions
Neutralizing Antigen
Agglutination of Antigens
Precipitation of Antigens
Activating Complement
Opsonization
Antibody-Dependent Cellular Cytotoxicity
describe neutralizing antigen (antibody functions)
antibody binds to toxin released by antigen and prevents from infecting us - so toxin will not reach target
what do mRNA vaccines do
allows your body to produce antigens
describe agglutination of antigens (antibody functions)
glues them together
prevent from travelling and easier to phagocytize
describe precipitation of antigens (antibody functions)
bring our of body fluid and hold them together
makes easier for phagocytosis
keeps antigen from preforming function
describe activating complement (antibody functions)
starts out with fist complement protein (inactive) and leads to membrane attack complement
bacteria find matching antigen = activates C1 complement (first complement protein now active - activates C1)
describe opsonization (antibody functions)
antibody binds microbe and opsonizes it
makes it more visible to phagocytes
describe antibody dependent cellular cytotoxicity (antibody functions)
via cytotoxic T cells
antigen response
what are complements
serum proteins
describe activating complement (antibody functions) - pathway
classical pathway - antigen antibody complexes –> complement activation –> opsonization of pathogens and killing of pathogens by membrane attack complex
describe activation of classical complement pathway by antibody binding to bacterial antigen
set off cascade and activate other complement member in family
complement proteins serve as pores in cell and leads to death
describe opsonization (antibody functions) in more detail
phagocytes have receptors specifically to FC branch of antibody
Recognition of antibody of certain class aids in phagocytosis
describe graph of rate of antibody production following initial exposure to antigen (~ 4 stages)
1 month scale
slow in beginning = do not have many of the lymphocytes with appropriate receptor on surface
then expand clones and increase rate and number of production of antibodies
peaks = have antibodies present for variable amounts of time - depends on specific antigen
end = antibodies broken down and fade away - higher concentration than initial but not much higher since infection is over
describe graph of rate of antibody production following subsequent exposure to same antigen
expanded clones and now have memory cells
so very rapid and much higher response that is longer lasting
what are the 3 main adaptive immunity components
lymphocytes must gain immunocompetence - develop antigen receptors
B cells - produce antibodies
T cells - cytotoxic T cells (CD8+) and helper T cells (CD4+)
why do we get sick
not fast enough or enough antibodies at first exposure
name the 3 types of T cells
cytotoxic T cells= CD8+
helper T cells =CD4+
regulatory T cells = CD4+
describe how lymphocytes develop antigen receptors
variable region on receptor has a variety of genes that encode for it = V,D, & J (joining)
each individual cell choses a V D and J segment
with help of RAGs
then choose one segment from constant region
describe RAGs
recognize splice sites at beginning of different segments and put them together to produce one possible outcome
recombination activating genes
what are TdT
Terminal deoxynucleotidyl transferase
can add single or multiple nucleotides at end of segments that have been joined
creates frameshift - so will have different output for that
allows infinite production of antigen receptors
what type of antibodies are produced during response (graph) and why
IgM produced first = best to activate complement system but too big to move well so switch to IgGs
IgGs = memory cells and expanded clones
also others like IgAs
describe process of making an antigen receptor
each choose V D J
use TdT to change receptor so its unique to specific B cell
M constant region to create IgM BUT can switch this constant region to a gamma segement to produce IgG
can plasma cells produce different classes of antibodies and why
one one variable region that will determine specificity but plasma cells can produce different classes (by switching constant region)
will the body create self antigens
usually - under normal circumstances = no
what is one way to recognize self
Major histocompatibility complex (MHC)
unique to each person, except in identical twins, important in tissue/organ transplant rejection
what is immune tolerance and explain
develops during fetal and early postnatal life due to clonal detection or clonal inactivation of cells that match body antigens
- basically get rid of any lymphocytes that have receptors that recognize own body
describe development of T cell tolerance in utero in the thymus - 3 concepts
T cells must recognize MHCII molecules - any T cells that cannot will be negatively selected (destroyed)
T cells should not recognize self proteins, cells expressing own MHCI - will be negatively selected
95% of T cells produced will be destroyed bc they are self reactive
how are T cells negatively selected (destroyed)
die by apoptosis
do cytotoxic T cells need recognition of antigen
yes
why do B and T cells response more rapidly if seeing same antigen
amplification due to production of memory cells
name the 2 types of antigens
exogenous
endogenous
describe endogenous antigens
produced by body cell
cytotoxic T cells must recognize it
describe exogenous antigens
foreign material
comes from outside body
name type of endogenous antigens and explain process
infected body cells (virally infected) =
synthesis of MHCI molecules
binding of peptide fragments to MHCI molecules
packing of antigen-MHCI complexes
insertion of antigen-MHCI complexes into plasma membrane
name the type of exogenous antigens and explain process
antigen presenting cells =
synthesis of MHCII molecules
binding of peptide fragments to MHCII molecules
packing of antigen-MHCII complexes
insertion of antigen-MHCII complexes in plasma membrane
describe process of cell mediated killing of virus infected cells
dendritic cell
intermediary = T cell receptor
T cell receptor releases cytokines = critical for activation of B cells and cytotoxic T cells
cytotoxic T cells must also recognize antigen
leads to killing of infected body cell by cytotoxic T cell (release of perforin and granzymes)
what do infected body cells present antigens use to present antigens to cytotoxic T cells
MHCI
signal that own body cells are infected or altered
describe how cytotoxic T cells kill virus infected cells
need cytokine from T help to lead to production and cell division then the many cells can kill using perforin and granzymes
name the 5 factors that alter resistance to infection
protein calorie malnutrition
preexisting disease
stress and state of mind
sleep deprivation
modest exercise and physical conditioning
describe protein calorie malnutrition (factors that alter resistance to infection)
greatest contributor to decreased resistance to infection worldwide
need appropriate materials to mount effective immune response
describe preexisting disease (factors that alter resistance to infection)
like if already fighting infection
infectious or non-infectious- can predispose body to infection
describe stress and state of mind (factors that alter resistance to infection)
can enhance or reduce resistance to infection and cancer
describe sleep deprivation (factors that alter resistance to infection)
associated with decreased immune function
describe modest exercise and physical conditioning (factors that alter resistance to infection)
net beneficial effects on immune system and host resistance
why do immunodeficiency diseases happen
results from weak, underactive or impaired immune system
like missing proteins or cells in immune system
describe SCID
severe combined immunodeficiency disease
immunodeficiency disease
a group of related diseases that arise from an absence of both B and T cells and some cases NK cells (could be caused by lack of cytokine needed for development of these cells)
describe AIDS
acquired immunodeficiency syndrome
immunodeficiency disease
infects and kills helper T cells (which are central in inactivation of B cells and cytotoxic T cells) resulting in impaired immune responses to infectious organisms
name 5 harmful immune responses
tissue/graft rejection
transfusion reactions
allergy - hypersensitivity
autoimmune disease
excessive inflammatory responses
describe rejection of tissue grafts or organs - why it happens
MHC-I proteins on graft cells and MHC-II proteins on the macrophages differ from recipients
recipients T cells recognize MHC proteins as foreign and cytotoxic T cells with the aid of helper T cells kill cells with foreign MHCs
how to avoid organ/tissue graft rejection.
radiation to eliminate dividing cells - rapidly dividing lymphocytes
drugs that kill actively dividing lymphocytes - decrease recipients T cell population
more susceptible to any other infections now
what is cyclosporine
drug that can help avoid rejection
blocks cytokine production from helper T cells
eliminates signals for proliferation of helper and cytotoxic T cells
what is a transfusion reaction
illness causes when rbcs are destroyed during blood transfusion
why would transfusion reactions happen
rbcs do not have MHC proteins (since no nucleus) but have plasma membrane proteins and carbohydrates that function as antigens
ABO system and Rh erythrocyte-membrane antigens
universal donor of blood
O
universal recipient of blood
AB
describe Rh factor
negative or positive
has medical important
describe Rh factor during pregnancy
if mom is + and baby is -
mom will attack baby if their bloods mix
usually happens during childbirth
so drug given to mom to ensure that mom does not attack baby
prevents mom blood from targeting blood of fetus in future pregnancies
describe blood group A (percentage of population, antigen on rbc and antibody in blood)
42%
Antigen on rbc = A
antibody in blood = anti-B
describe blood group B (percentage of population, antigen on rbc and antibody in blood)
10%
Antigen on rbc = B
antibody in blood = anti-A
describe blood group AB (percentage of population, antigen on rbc and antibody in blood)
3%
Antigen on rbc = A & B
antibody in blood = neither anti-A OR anti-B
describe blood group O (percentage of population, antigen on rbc and antibody in blood)
45%
Antigen on rbc = NEITHER A or B
antibody in blood = BOTH anti-A and anti-B
what is an allergic reaction
overly reactive to substance that most tolerate well
due to exogenous antigens
some people react to things that others will not
name the 2 types of allergic reaction
immediate hypersensitivity
delayed hypersensitivity = appears 12-72 hours after allergen exposure
describe function of mast cells in allergic reactions
mast cells filled with histamine granules
in small amounts histamine good since recruits immune cells to site of injury
too much = get into blood stream and systemic effect
also happens with basophils since also filled with histamine
what is anaphylaxis
allergic symptoms usually localized to site of antigen entry
if large amounts of mast/basophil cells chemicals enter circulation = causes severe hypotension (low bp) and bronchiolar constriction = anaphylaxis = can cause death due to circulatory and respiratory failure
what is autoimmune disease
inappropriate immune attack triggered by body proteins acting as antigens
what is immune attack of autoimmune disease consist of
immune attack is mediated by autoantibodies and self reactive T cells
direct against body cells that contain these proteins (proteins acting as antigens)
name 4 types of autoimmune diseases
type 1 diabetes mellitus
rheumatoid arthritis
multiple sclerosis
myasthenia gravis
describe myasthenia gravis (autoimmune disease)
against a nicotinic acetylcholine receptor that is expresses on muscles
make antibodies against muscle receptors and leads to paralysis
what can dampen immune response
regulatory T cells dampen immune response - possible research area for autoimmune diseases
