c39 lec 8 and 9 Flashcards
what is our first line of defense in our bodies (physical barrier to prevent infection)
skin
external barrier
our epithelial cells are coated in _____ to protect epithelium and prevent infection
mucus
thats why they are called mucosal surfaces/mucosa
most infections actually occur through _______ surfaces rather than our skin
mucosal surfaces
why?
mucosal surfaces has a much larger surface area = more immune cells
comprises all specialized lymphoid tissues for mucosal surfaces
MALT: mucosa-associated lymphoid tissues
- GALT and other fall under MALT
the gastrointestinal tract is lined with
mucus and commensal bacteria
what does commensal bacteria do in our gastrointestinal tract?
helps us degrade and digest food
tonsils and adenoids (secondary lymphoid tissues) surround the entry point to the gastrointestinal and respiratory tracts
waldeyer’s ring
GALT stands for
gut associated lymphoid tissue
projections in the gut that aid in nutrient absorption
villi
what are the five benefits of commensal bacteria
- synthesize essential metabolites (ex. vitamin K)
- break down plant fibers in food
- inactivate toxic substances in food or made by pathogens (before our immune cells even see them)
- Prevent pathogens from benefiting from the resources of the human gut
- interact with epithelium to trigger development of secondary lymphoid tissue
____ dimers protect our mucosal surfaces (what type of immunoglobiulin)- MALT
IgA dimers
bring it in via transcytosis
receptor mediated transport from one side of a cell to the other
transcytosis
what maintains microbiome populations, keeps population growth in check (neutralize) and prevent it from overgrowing and infecting us
IgA
along with IgA what also protects our mucosal tissues
IgM
- activated adaptive immune response constantly = consistent antibody production
as well as IgG: helpful in lower respiratory tract and urogenital tracts
do we have any complement pathway in mucosal tissues?
NOPE
made of glycoproteins, mucins (proteins), that provide viscous and protective features
mucus
very stick proteins that have simple sequence repeats
____ polypeptides are linked by disulfide bonds and form huge networks
sticky because of a lot of carbohydrate residues
mucins
secrete mucus
goblet cell
produce AMPs (Antimicrobial Peptides)
paneth cell
epithelial cells and lamina propria (connective tissue with immune cells and structures)
mucosa
bring antigens into the lumen of the intestines
M cells
specialized epithelial cells in GALT passing antigen from intestinal lumen to intestinal wall (lamino proprai)
M cells
help us constantly monitor the gut lumen
M (microfold) cells
M cells transport antigens to
peyer’s patch
can capture antigen from gut lumen by extending processes between intestinal epithelial cells
dendritic cells
disturbances to the environment cause
inflammation
for mucosal infections we don’t want
a lot of inflammation, not alot of requirement of immune cells because we mostly just use what we already have to deal with the problem
and don’t break down the tissue so no need to repair (repair causes a big immune response)
what are the two strategies that mucosal immunity employs?
- low inflammation: avoid tissue damage and prevent worse infections
- proactive: constantly producing an adaptive immune response towards commensal bacteria
intestinal macrophages are
non-inflammatory
- they are phagocytic
- do not contribute to inflammation, do NOT produce cytokines
inflammation anergic
but remember that intestinal epithelial cells create local inflammation
intestinal epithelial cells use ____ and _____ receptors to recognize bacteria that passed through mucus ….intestinal epithelial cells create local inflammation
TLRs and NOD
mucosal cells don’t do good with
inflammation
significant reduction of infection due to majority of population being immune
herd immunity
What are the types of vaccines (4):
- weaken the virus
- inactivate the virus (heat or chemically inactivate the virus)
- use part of the pathogen
- use part of the genetic code
live, weakened virus grown in non-human cells = strong immune response
not suitable for immunocompromised patients
live-attenuated viruses
describe the new generation of the live-attenuated viruses
we delete the virulence gene and this makes it harder for the virus to revert to wildtype infectivity = safer for immunocompromised patients
heat or chemically inactivating the virus is used for ______ patients
immunocompromised patients
requires multiple doses
only uses the specific parts of a virus or bacterium that the immune system needs to recognize
protein subunit vaccines
- no genetic material, cannot replicate = not as strong immune response
- suitable for immunocompromised patients, requires multiple doses
what is a type of subunit vaccine where protein is attached to carbohydrate to elicit an immune response
conjugate vaccine
conjugate vaccines ( a type of subunit vaccine) uses what as the protein
toxoids (inactivated toxin)
what makes a conjugate vaccine better than a polysaccharide vaccine?
it induces activation of Helper T cells
how do vaccines against bacterial diseases differ from vaccines for viral diseases?
they target toxins instead
only bacterial vaccines target toxins because viral diseases don’t make toxins
a modern approach to vaccine development that starts with analyzing the genome of a pathogen (like a bacterium or virus) to identify potential vaccine targets, rather than starting with the pathogen itself in the lab
reverse vaccinology, why we are able to come up with vaccines so fast
increase the vaccination immune response
adjuvants
can create a depot (storage) = slow, controlled release of vaccine
adjuvants
may be added to a vaccine to mimic danger signals and catch the attention of the immune system
an adjuvant
what do we not have a vaccine to yet?
HIV
- it mutates so rapidly, integrates into host DNA and evades our immune system
- attenuated vaccines are unsafe
- our attempts to make a successful vaccine keep failing
some HIV patients that manage the idsease better have
broadly neutralizing antibodies (BnAbs)
for respiratory viruses, they are trying to replace muscular vaccines with _____ vaccines to trigger a mucosal immune response
intranasal vaccines
(up ur nose hole)
what is one cancer vaccine that has been successful
gardasil vaccine to prevent HPV, prevent cervical cancer
antigen-based cancer vaccines target
neoantigens
prostate cancer vaccine in use in prostate cancer patients
provenge
mutation allows for escape from _____
immunity
yearly changes in influenza viruses: slow changes
antigenic drift
outbreak within a population
epidemic
influenza viruses are typically epidemic
fast changes in viruses
antigenic shift
worldwide outbreak of infection
pandemic
co-infection results in an exchange of genetic information and generates more competitive virus
recombination
ross link receptors together to trigger broad T cell activation
superantigens
superantigens cross-linking receptors together to tripper broad T cell activation can lead to
Ex. 2-20% of T cells activated instead of 1 in 10 000
toxic shock syndrome
have proteins that disrupt antigen processing and presentation on MHC class I proteins
viruses
genetic process where one DNA sequence is non reciprocally copies over another, making them more similar or identical
gene conversion
viruses that hide from our immune system
latent viruses
_____ infection causes immune amnesia
measles
arise from absent or defective component in either innate or adaptive immunity
immunodeficiencies
immunodeficiency inherited through genetics
primary immunodeficiency
immunodeficiency due to environmental factors (ex. malnutrition, viral infection,etc)
secondary immunodeficiency
microbes that do not affect healthy individuals but infect immunocompromised individuals
opportunistic infection
what does HIV lead to
AIDS (acquired immunodeficiency deficiency syndrome)
slowly depletes CD4 T cell population
HIV
another name for mono or the kissing disease
EBV
EBV (or mono or kissing disease) can trigger what
multiple sclerosis
how an EBV infection trigger the development of Multiple sclerosis (MS)?
EBV has a surface antigen that is similar to a protein on the myelin sheath
when our bodies protect against EBV infection and get rid of EBV infected cells, we create B cells and T cells to do so
but since the surface antigen is similar to the protein on the myelin sheath, the T cells and B cells might target the myelin sheath and degrade that instead leading to MS
how come immune responses to HIV rarely eliminates virus
due to rapid maturation rate = progression to immunodeficiency
AIDS is a _______ immunodeficiency
secondary
has helped majority of population of infected HIV individuals prevent progression to AIDS
anti-retroviral therapy (ART) / combination therapy
because we want to target all 5 stages of HIV development
multiple anti-viral drugs
combination therapy or ART (anti-retroviral therapy)
allows for increases T cell numbers and prevention of AIDS
anti-retroviral therapy (ART) or combination therapy
HIV has ______ for viral entry
co-receptors (additional to CD4)
initial HIV infections come from
R5 viruses (M-tropic)
what are the two types of HIV viruses that can infect us
X4 virus : T tropic
X5 virus: M tropic
why is the CCR5 mutation is beneficial for HIV infection
because those with this mutation don’t get R5 HIV infection!
because R5 binds to CCR5 and CD4
X4 (t tropic) HIV virus binds to
CD4 and CXCR4
R5 (m tropic) virus binds to
CD4 and CCR5
