Features of Innate Immunity
- Specificity:
- Receptors:
- Kinetics:
- Potency:
- Phase:
- Memory:
- Specificity: Recognizes conserved motifs or patterns
- Receptors: Germline encoded (inherited), TLRs, etc.
- Kinetics: Very fast to start, short acting
- Potency: Low/moderate
- Phase: Single
- Memory: No
Features of Acquired/Adaptive Immunity
- Specificity:
- Receptors:
- Kinetics:
- Potency:
- Phase:
- Memory:
- Specificity: Recognize a diverse range of specific epitopes
- Receptors: Recombination of and mutation of germline: TCR, antibodies
- Kinetics: Slow to start (takes time to generate the right receptors?), long acting
- Potency: High
- Phase: Biphasic (very rapid the second time once your acquired immune response has been primed against)
- Memory: Yes
Adjuvants
They potentiate immune responses. Any substance that acts to accelerate, prolong, or enhance ANITGEN-SPECIFIC acquired immune responses
Clonal Selection Theory and its 4 predictions
- Each nascent lymphocyte generates a single receptor with unique specificity.
- Lymphocytes bearing receptors that are self-reactive are deleted during development.
- Binding of the receptor to its specific antigen ligand causes activation of the lymphocyte and when antigen is eliminated, the immune response ceases.
- Lymphocyte activation results in the expansion of that cell, forming a clonal population of effector cells each bearing the identical receptor as the parent.
Immunity
A condition of being able to resist (NOT eliminate) a pathological threat by preventing its proliferation or by counteracting the effects of its products
Most of the immune system is innate, adaptive cleans up like 5% of the pathogens - only a small amount gets past the innate immune system, innate does most of the work
Functions of immune systems
- Recognize and defend against threats including pathogens, genetic damage, cellular stress etc.
- Generate neo-receptors specific to antigens
- Expand/activate cells expressing neo receptors
- Delete receptors that are “self” reactive
- Avoid self-damage (autoimmunity)
Why does deficiency in just innate immunity result in poorer
control of infections than deficiency in just adaptive immunity? (graph on slide 8)
- Innate immune responses breaks up stuff (phagocytes) for dendritic cells to present to the adaptive immune system
- Deficiency in innate immunity = deficiency in adaptive immunity
Antigen
A chemical substance (usually a macromolecule) to which an acquired immune response is generated.
Cytokines
- small 2nd messenger proteins that bind to receptors on other cells - allows immune cells to communicate with each other
When things get past the physical barriers they are recognized by
- Patter Recognition Receptors (Toll like receptors) (PAMPs and DAMPs) (recognize things like bacterial cell wall material)
Innate immune system is turned on by
- Pattern recognitions of PAMPs and DAMPs
- They are detected by pattern recognition receptors - these receptors are on all cells but are in higher number on immune cells
True or False: Immune system only discriminates between self and non-self
False: it also discriminates between safe and dangerous
The bone marrow (hematopoietic system) produces ___ and ____
- Erythrocytes (red blood cells)
- Leukocytes (white blood cells)
Innate Immunity
- Host-defense mechanisms without specificity to a particular pathogen.
- recognizes basic patterns common to classes of pathogens.
- An early barrier to infectious disease based on mechanisms that pre-exist (encoded in the germ line).
- Signals “danger” and is critical to inducing acquired immune system activation.
PRR binding triggers
release of cytokines, chemokines,
and other small mediators of inflammation
PAMPs (pathogen associated molecular patterns)
- invariant molecules on pathogens
they bind to pattern recognition receptors (PRRs) on DCs, macrophages, neutrophils, lymphocytes etc.
All lymphocytes are formed in
bone marrow, B cells are mature when they leave, but T cells need to go to the thymus to be educated
DAMPs (danger-associated molecular patterns)
- self patterns from necrotic cells or mutations
Acquired immunity is only found in
vertebrates (innate is found everywhere)
Adaptive immunity
Acquired immune responses are directed against specific “antigenic epitopes”.
Lymphatics
- Where immune cells go when they extravasate out of the blood into the tissue space.
- parallel system of endothelial vessels
- Is not a circulatory system (no pump).
- “Drain” most tissues.
- Tributaries join together and most lymph enters the blood stream through the
thoracic duct.
Lymph nodes function
- bring together immune cells to catalyze and target immune responses to where they (lymph node) are
Spleen
- no connection to the lymphatic system, lymph node for pathogen circulating in the blood
