Immunity an overview Flashcards by Allison Cotter

Define immunity, adaptive immunity and innate immunity

immunity-the state of being immune to or protected from a organism or foreign agent
adaptive immunity- dynamic protection results from specific immune components changing or adapting to unique features of the pathogen or foreign agent
Innate immunity-inherent protection against organisms that are permanent from birth

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WHat is passive immunity

receiving preformed antibody
rapid protection
short duration T1/2 for Ab is 3 weeks

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What is active immunity

exposure to a foreign antigen

slow protection

long duration-memory lymphocytes

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Immunogen

a molecule that induces an immune response

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antigen

a molecule that binds to (is recognized by) adaptive immunemediators

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toleragen

a molecule that induces immune unresponsiveness to subsequent doses of the molecule

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how does size of a substance influence its immunogenicity

large=increased immunogenecity

small=decreased immunogenecity

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How does dose influence immunogenecity

Intermediate dose=large immunogenecity

high or low dose=decreased immunogenecity

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How does route of administration influence immunogenecity

SubQ> Intraperitoneal > Intravenous > Intragastric

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How does composition influence immunogenecity

complex= increased immunogenecity

simple=decreased

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How do adjuvants influence immunogenecity

bacteria=increased

no/few bacteria=decreased

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How does interaction with MHC complex influence immunogenecity

effective=increased

ineffective=decreased

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Is the invadin antigen or microbe self or foreign?

self-:tolerogenic immune response against self antigens

foreign/non-self: mount an innate or adaptive immune response to the antigen or microbe

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What controls specificity both for innate and adaptive immunity

Innate: Pattern-recognition receptors-limited diversity
- TLR, Nod-like receptors
- complement proteins
Adaptive: Antigen recptors
- T cell receptor (TCR)
- B cell receptor (BCR)

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Describe the memeory for innate and adaptive immunity

innate: none
adaptive: memory B and T cells

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WHat does it mean if an invading antigen or microbe is intracellular? How about extracellular?

Intracellular: located within the cells cytoplasm or within a cell vacuole

Extracellular: outside cells, either soluble or associated with the external surface of cells

Primary vs Secondary Immune Responses

primary immune response: response to the initial exposure to the substance, slow onset
Secodnary immune response: more rapid and stronger response to subsequent exposure to substance. fast onset after second exposure

What is a live-attenuated vaccine and what does it mostly induce?

What are pros and cons?

micro-organism is modified to decrease pathogenecity, limited growth after injection
mainly induces: cellular response (T cells)
PROS: strong life-long immunity
CONS: may revert to virulent form

What is an inactivated vaccine and what does it mostly induce?

What are pros and cons?

pathogen is inactivated (heat or chemically) but retains an immunolgic epitope on surface
mainly induces: Humoral Response (B cells)
PROS: stable and safer than Live
CONS: Weaker immunity, requires boster

WHat 3 things help the body make immunologic decisions?

cells, soluble mediators, surface receptors

What are generative immune organs?

What are peripheral immune .organs?

Generative immune organs:
- bone marrow
- thymus
Peripheral immune organs:
- lymph nodes
- spleen

What is innate immunity

Always present
Respons immediately
comprised of
1. epithelial barriers
2. phagocytic leukocytes (macrophage, neutrophil)
3. Natural killer cells
4. Plasma proteins such as complement

What is adaptive immunity

normally silent-activated to adapt and neutralixe pathogens (antigen specific)
respond slowly to first exposure
memory: faster response to subsequent exposure
comprised of: T cells (cell-mediated immunity) and B cells (humoral immunity)

Describe the function, characteristics and mechanism or innate immunity

Function: provide primary defense against invading pathogens
characteristics: immediate response always ON and doesn’t require previous exposure for activation
Mechanism:
- natural barriers (epithelium-skin, mucous membranes)
- phagocytic cells-macrophages, neutrophils
- Dendritic cells
- Natural killer cells
- Alternative lectin complement pathway

How is the innate immune system activated?

* Patter Recognition Receptors (PAMP) on bacteria, virus, fungal or parasite pahtogens. e.g.: TLRs * this actiavtes a defined series of proinflammatory or antiviral signaling * there is NO MEMORY so the response will be immediate and the same to the subsequent infection.

Describe the function, characteristics, and mechanism of adaptive immunity

* Function: provide antigen specific defence * Characteristics * must be activated by invading antigen * cascade of events * prepare for future defense=**immune memory** * mechanism: T cell and B cell

How is the adaptive immune system activated?

* antigen-a molecule that binds to an Antibody or T cell receptor * epitopeL the specific portion of the macromolecular antigen recognized by receptors expressed on lymphocytes * Antibody (B Cell receptor): recognize eptiopes on macromolecular proteins and lipids * T Cell Receptor: recognize epitopes on peptide fragments complexed with either an MHC class I or MHC class II presentation molecule

Describe the T Cell Response

* T=thymus * function: antigen specific immune response to ***_Intracellular pathogens_*** * Types activated by different antigen presentation styles * cytotoxic=CD8: MHC class I restrcited and the goal is to KILL! * Helper=CD4: MHC class II restrcited and the goal is to recruit/activate * cytokine secretion * CD40:CD40L

Describe the B cell response

* B=Bone Marrow * funciton is antigen specific immune response to ***_extracellular pathogens/antigens_*** and immune surveilance * types=plasma cells * secrete soluble antibodies and have isotypes (IgM, IgG, IgA, IgE)

List the cells of the innate immune system

* phagycytes * neutophils * macrophages * Granulocytes * eosinophils * basophils * mast cells

WHat cell link the innate and adaptive immune systems?

dendritic and natural killer cells (NK)

What are the cells of the adaptive immune system

lymphocytes

CD4 T cells - function - key markers

function: B cell differentiation, macrophage activation key markers: CD3, CD4

CD8 T cells functions key markers

function: Kill microbe infected cells, tumor cells Key markers: CD3, CD8

Regulatory T cells function key markers

* function: supress T cell function * key markers: CD3, CD4, CD25

B Cells ## Footnote function key markers

function: Produce Ab key markers: FcR, CD19, CD21

NK Cells ## Footnote function key markers

function: Kill virus-infected cells, damaged cells, tumors key markers: CD16, FcRy

What are the primary (generative) lymphoid tissues and describe them? Do th same for secondary, what are they?

1. **Primary:** * _bone marrow_: hematopoietic progenitors, lymphocyte development * naive lymphocytes (small) * mature lymphocyte( larger0 * _thymus:_ development and maturation of T lymphocytes 1. **Secondary** * _lymph nodes_ * _spleen_ * Mucosal or skin associated lymphatic tissue (MALT/SALT) * peyers patches, tonsils