Innate Immunity Lecture Notes

Flashcards about Innate Immunity

Innate immunity

Protection against infection

Innate immunity

Protection against infection via external barriers, if breached, organism encounters innate response

Innate Response

Support recruited from adaptive response

Haematopoietic stem cells

Self renewing and multipotent

Innate response cells

Come from myeloid pathway

Neutrophils

Stays as neutrophil

Monocytes

Phagocytic, leave blood and differentiate in tissues to macrophage, longer half life

Dendritic cells

Follicular cell, not phagocytic, remaining are mostly phagocytic

Oxidative killing

Reactive oxygen intermediates

Reactive oxygen intermediates

O-2 (superoxide)

Reactive oxygen intermediates

H2O2 (hydrogen peroxide)

Reactive oxygen intermediates

OH- (hydroxyl radical)

Reactive oxygen intermediates

OCl- (hypochlorite)

Nitric oxide-related killing

Reactive nitrogen intermediates

Lysozyme

Non-oxidative killing mechanisms

Defensins

Non-oxidative killing mechanisms

Lactoferrin

Non-oxidative killing mechanisms

Proteases

Non-oxidative killing mechanisms

Eosinophils

Act against large parasites + Release granule contents, extracellular killing

Eosinophils

Major basic protein, cationic protein, oxygen metabolites, perforins

Molecules of innate immunity

Pattern recognition receptors (PRR)

Complement

Integrated system

Fc receptors

Binds IgE

Acute phase proteins

Enhance host resistance to infection, minimize tissue injury and promote resolution and repair of inflammatory lesion

Complement

integrated system + Cleavage of C3 and C5 at the core

Opsonization

Complement receptors and Fc receptors facilitate phagocytosis

Certain cytokines released in response to activation of PRRs

Act on the liver to increase secretion of acute phase proteins (APPs)

Cytokines

Small secreted proteins that act as messengers between cells

Main groups of cytokines

Interleukins, colony stimulating factors, chemokines, interferons, tumour necrosis factors

Cytokines function

Control of haematopoiesis and immune responses

Cytokines

Bind to specific cytokine receptors which initiate intracellular signalling

True statement

Allergies are a side-effect of mast cell and basophil action, the act of engulfment of pathogens is not sufficient to actually kill the pathogen

Myeloid progenitor cell lineage

Macrophage, mast cell, megakaryocyte

Event that happens first in the Complement system

C3 is cleaved

Proteins that can help a phagocyte detect an opsonized microbe via direct physical contact with the bound antibody

Fc receptors, complement receptors