Chapter 4 Flashcards
immunology?
study of the bodies defense against infection
Non-self materials are termed _____ (coined from their ability to cause antibody generation)
antigens
If an antigen has the potential to elicit an immune response it is termed an ________
immunogen
are all antigens immunogens?
no
immunity involves what 3 interrelated systems?
- Physical, chemical & thermal barrier systems
- Innate immune system
- Adaptive immune system
why is skin a good physical barrier?
- tough
- thick as callus
- water proof
- resident immune cells
mucosae is a physical barrier where?
- oral cavity and gastrointestinal tract
- respiratory trat
- urogenital tract
- ocular orbits
- middle ear
physiological barriers include s temperature which does what?
normal body temperature inhibits growth of many microorganisms
Elevated body temperature ______ is one of the most important defense mechanisms against infections
fever
Low_______ inhibits growth/attachment of most microbes and can kill them
ph
role of pepsin
digestive enzyme which hydrolyzes proteins
role of lysozyme
hydrolytic enzyme found in mucous secretions is able to cleave the peptidoglycan layer of the bacterial cell wall
Lactoperoxidase
generates toxic superoxide radicals that kill microbes
chemical barriers include anti-microbial substances which directly destroy microorganisms through two ways:
defensins:
- produced in the skin, respiratory tract, small intestine
- damages cell membranes
surfactant proteins:
- present in lungs
- enhance the efficiency of phagocytosis
immune response
The responses against a potential infection is collectively called the
what is the difference between the innate immune repsonse and the adaptive immune response?
innate:
- Immediately available to combat pathogens
- Does not lead to lasting immunity
- Non-specific
- general response that can be mounted by any cell in your body
- germ line encoded
- fast response
- no memory
Adaptive immune response:
- Developed during the lifetime of an individual
- Leads to lasting immunity
- Specific
- slower response to mount
- memory
- specific to invading pathogen
what are the two types of antiviral immune responses?
- Humoral
- B cells producing antibodies that specifically recognize the invading virus - T cell-mediated
- T cells with receptors that specifically recognize the virus-infected cell
the immune system can remember seeing the virus and respond faster and stronger with its second exposure with ________ _____ cells and ___ -_____
memmory B cells and T cells
the 1st step of Induction of the inflammatory response is?
Cytokines and chemokines stimulate the induced innate response
the 2nd step of Induction of the inflammatory response is?
Induced innate immune response occurs if primary response is unsuccessful
the 3rd step of Induction of the inflammatory response is?
The adaptive immune response is initiated IF the innate response fails to eliminate the pathogen
describe the innate immune response
- front line of defense against viral infection
2. acts as a bridge stimulating the adaptive immune response
cell based immunity includes what cells?
- type I IFNs and ISGs
- specialized cells
- phagocytes, neutrophils
- NK cells
- NK T cells and B1 cells
describe cell based immunity
- motifs produced by the virus ( Pathogen associated molecular patterns (PAMPs))
- PAMPs essential for virus replication and do not change rapidly or cannot change
- Recognized by pattern recognition receptors (PRRs) expressed by the cell (germ line encoded)
- PRR/PAMP interaction triggers signaling cascades within the cell
what are viral PAMPs?
- surface proteins
- glycoproteins and other envelope proteins
- nucelic acids
- Host mRNAs have 5’ caps
- ssRNA molecules with 5’ triphosphates
- long distance dsRNA molecules
Host cell PRRs include
- RIG-I-like receptors (RLRs)
- Nod-like receptors (NLRs)
- Class A scavenger receptors (SR-As)
(*) macrophages do what ?
- phagocytosis and activation of bacterial mechanisms
- antigen presentation
(*) dendritic cells do what?
antigen uptake in peripheral sites
- atigen presentation
dendrtic cells form bridges between ________ and ______
innate immunity and adaptive immunity
(*) neutrophils
phagocytosis and activation of bactericidal mechanisms
(*) eosinophil
killing of antibody coated parasites
(*) basophils
promotion of allergic responses and augmentation of anti parasitic immunity
(*) mast cells
release of granules containing histamine and activate agents
natural killer cells are activated by ______ and _______
cytokines and by oposonisation
NK cell activity is controlled by a balance between _____ and _____ signals
activating and inhibitory
what are cytokines?
- Small molecules (~25kD) released by a variety of cells in response to activating stimuli
- Bind to specific receptors on other cells and thereby influence their behaviour
- Chemical messengers of the immune system
what are the cytokines families
- Hematopoietin family (~50 members)
- Tumor necrosis family (TNF)
- Interferon family (IFN)
- Chemokines
cytokines can have ___ and ____ effects
local, systemic
what are interferons?
- Interferons (IFNs) are cytokines and are essential for immune responses
- Anti-viral, anti-proliferative and immunoregulatory functions
what are the 3 groups af interferons?
- Type I IFNs α IFNs, β IFN
- Type II IFN γ IFN
- Type III IFN λ IFN
what is the function of interferons?
- Induce expression of IFN-stimulated genes (ISGs)
- Interferon regulatory factors (IRFs) function as transcription factors to induce expression of ISGs
- Cancer cells often possess defects in IFN singling
what does type 1 IFN do?
- Binds to the IFNAR on the surface of cells
- Activates a signaling cascade (Jak/STAT)
- Triggers to production of interferon stimulated genes (ISGs)
- Leads to the establishment of an antiviral state
