Studied by 5 peopleDefine: Innate Immunity
The immune system we have at birth, first and fastest response to pathogens, non-specific (recognizes self vs. non-self)
What does our innate immune system consist of?
Barriers
Anti-microbial peptides
Complement
Soluble mediators
Phagocytes, and Granulocytes
Define: Adaptive Immunity
The immune system develop over time, specific but slow response to pathogens, recognizes/evolves over the course of an infection. Present only in vertebrates -Consists of B-Lymphocytes and T-Lymphocytes Very tightly regulated (mistakes can lead to autoimmunity/immunosuppression)
Define: Humoral Immunity
The aspect of immunity that is mediated by macromolecules located in extracellular fluids. Humoral immunity is named so because it involves substances found in the humors, or body fluids.
Define: Cellular Immunity
A protective immune process that involves the activation of cells to fight off pathogens.
What are examples of barriers?
All surfaces where the body interacts with the outside world: skin, lung surface, intestinal surface.
Define: Anti-microbial Peptides/Proteins
Present in secretions (sweat, mucus, tears, salvia)
Rich in positively charged amino acid residues
Disrupt microbial membranes, activate lytic proteins, inhibit DNA/RNA/protein synthesis (inhibits reproduction of invasive pathogens) -Capable of target lysis in minutes
Define: Complement
Soluble (humoral), preformed, inactive proteins that breakdown a microbial cell once it recognizes it
Coats target cell with complement proteins resulting in lysis
Binds directly to a microbial cell surface, or to antibodies which have coated the cell
Define: Soluble Mediators
Cell level hormones, rapidly released by infected cells (warning sign)
Control physiology/actions of host/nearby cells Includes: Acute proteins (complement), Interferons (induce fever/general antiviral state) Cytokines/Chemokines (how white blood cells communicate and work at infection)
Define: Phagocytes/Granulocytes
Found throughout the body
Non-clonal (all identical)
Activates immediately after recognition of target (self vs. non self)
Directly kills target (phagocytosis, release of toxic compounds)
Activates adaptive immune response
Define: Non-Clonal
All progeny are identical (clones/replica of each other)
Which factors of the innate immune system are capable of target recognition?
Anti-microbial peptides, Complement, Soluble mediators, and Phagocytes + Granulocytes: Differentiate between self and not-self
Barriers have no target recognition, they keep everything out.
How does the innate immune system recognize pathogens?
Pathogen Associated Molecular Patterns(PAMP) which don't exist in our own cells.
Give examples of PAMPs
Unmethylated RNA/DNA Polysaccharides Lipids dsRNA (double stranded RNA) Flagella Formulated peptides (formal groups on protein)
Define: Opsonization
The process of making a foreign cell more susceptible to phagocytosis by coating the cell with specific antibodies that phagocytes to recognize and consume.
Why doesn't the innate immune system have memory?
Innate cells die after immune response, and no memory cells are formed. No advantage in keeping cells around since they aren't pathogen specific, and the immune response will never get any better or faster
Define: Autoimmunity
Adaptive immune system mistakes self for pathogen, body attacks itself.
Define: Immunosuppression
Adaptive immune system mistakes pathogen for self, pathogen flourishes in body without immune response.
Explain the target recognition of the adaptive immune system.
Incredibly exact/precise immunity, capable of killing/targeting a single infected cell without damaging surrounding cells.
Explain: Lymphocyte Specificity
Adaptive immune system recognizes individual pathogens
Capable of differentiating between similar pathogens (annual influenza)
Recognizes specific residues on targets
Targets the one cell without damaging neighbouring cells
Explain: Lymphocyte Diversity
The adaptive immune system's ability to generate diversity for identifying pathogens by rearranging small gene fragments to have an infinite amount of receptors to recognize pathogens
Explain: Lymphocyte Selection
Disposes of genetic shuffling that results in cells with receptors that recognize our own cells (attacks self) failure to eliminate auto-reactive cells results in autoimmunity
Explain how the adaptive immune system "learns" or reacts to many different pathogens
About 1 in every 10000 lymphocytes recognize any single pathogen, once one recognizes a pathogen we select these cells and expand/replicate them (cell proliferation) as these these cells proliferate, their receptors evolve to be the best at recognizing pathogens,
Define: Clonal Theory
A single cell gives rise to a variation of different lymphocytes, after the removal of self-reactive and immature lymphocytes, a single lymphocyte will recognize a single pathogen, that lymphocyte is then proliferated (activated/replicated)
What are the four postulates of clonal theory?
Each lymphocyte is unique and bears a single unique receptor
Interaction between a foreign particle and a lymphocyte receptor leads to lymphocyte activation
Any lymphocyte that attacks self (self-reactive) is destroyed before it can mature
An activated lymphocyte will proliferate resulting in daughter lymphocytes which bear receptors identical to that of the parent
Explain: Adaptive Immunity Memory
During an immune response, some lymphocytes diversify into long-lived memory cells. These memory cells survive a lifetime (we'll always have them)
Unlike the innate system, there is an advantage to keeping these cells around, they specifically recognize pathogens and are very efficient
Capable of evolving/improving resulting in greater/faster responses when re-infected with a previous pathogen
Explain: Adaptive Modulation of Innate Immunity
Highly specific antibodies produced by B-lymphocytes bind to target cells resulting in: Complement activation and/or tagging targets for phagocytes (via soluble mediators)
Adaptive helps eliminate targets while minimizing collateral damage, modulating inflammation and down-regulating innate response.
Explain: Innate Modulation of Adaptive Immunity
Activation of T cells require phagocytosis and digestion of pathogen by cells of the innate system (macrophages/dendritic cells) Once the pathogen is digested it is presented to the lymphocyte to "see" and recognize. Innate immune system cells also send a second signal out to signal full lymphocyte activation after the lymphocyte has "seen" the pathogen.
Where are the majority of the body's immune resources directed?
Barriers, this massive interface is our first level of protection, and requires lots of maintenance
Define: Non-Clonal
Progeny are identical
Explain the difference between the response time of the innate and adaptive immune systems
Innate: Immediate response (Minutes/Hours) Adaptive: Days
Explain the difference between the specificity of the innate and adaptive immune systems
Innate: Recognizes general molecular patterns (PAMPs) self vs. non-self Adaptive: Highly specific recognition of particular pathogens
Explain the difference between the diversity of the innate and adaptive immune systems
Innate: Germline encoded, very limited diversity Adaptive: Capable of genetic rearrangement, highly diverse
Explain the difference between the memory of the innate and adaptive immune systems
Innate: None Adaptive: Persistent memory, faster and better secondary responses
Explain the difference between the soluble components of the innate and adaptive immune systems
Innate: Anti-microbial peptides/proteins, interferon complement Adaptive: antibodies
Explain the difference between the cellular components of the innate and adaptive immune systems
Innate: Phagocytes, granulocytes, natural killer cells, dendritic cells Adaptive: B and T lymphocytes
Explain the difference between the self/non-self discrimination of the innate and adaptive immune systems
Innate: Nearly perfect Adaptive: Good, but failures are very bad (autoimmune diseases)
Note
Flashcard