Innate Immune Barrier Overview

know table

know table

	Innate	Adaptive
Cells	Myeloid-lineage	Lymphocytes
Molecules (receptors/ligands)	PRR’s PAMPs/MAMPs	CD4, CD8, etc. MHC
Time	Fast initial response (min)	Delayed initial, fast secondary (days)
Clonality	Polyclonal receptors	Monoclonal receptors
Diversity	Limited number of patterns	Greater diversity potential
Memory	Limited memory (inheritance)	Extensive memory system
Soluble components	Cytokines	Also use cytokines
Self/Non-self distinction	Very good	Also very good

3 types of barriers

physical, cellular, chemical

Skin innate immunity

proteases, DNAses, RNAses (more RNAses)

Mouth innate immunity

Enzymes, antimicrobial peptides, flow of fluid toward stomach

Stomach innate immunity

low pH, digestive enzymes, bile salts, antimicrobial peptides, fluid flow to intestine

Small intestine innate

digestive enzymes, antimicrobial peptides, flow to large intestine

Large intestine innate immunity

Intestinal flora compete with invading microbes, fluid/feces expelled from rectum

Airway and lungs innate immunity

Cilia sweep mucus, coughing, sneezing expel mucus, macrophages in alveoli

Urogenital tract innate immunity

flushed by urine and mucous, low pH, antimicrobial peptides and proteins

Salivary, lacrimal, mammary gland innate immunity

Flushed by secretions and mucus, antimicrobial peptides and proteins

lysozyme

found in tears, saliva, respiratory fluids and cleaves the peptidoglycan component of bacterial cell walls

lactoferrin

bind iron ions so microbes can’t use them for metabolism

Calprotectin

binds calcium and divalent cations so microbes can’t have them for metabolism

Psoriasin

produced by skin, has antibacterial activity against Ecoli

Anti-microbial peptides

smaller than antimicrobial proteins, can infiltrate bacteria cell membranes, include defensins, cathelicidin,, histatins, and dermicidin

Defensins

skin/mucosal epithelia, fight bacteria, fungi, protozoan, and viruses, can have intracellular toxicity

Cathelcidin

mucosal epithelia, fight bacteria, can have intracellular toxicity

Hisatins

saliva, lectins fight fungal infection

Dermicidin

skin (sweat), antibacterial/fungal

Surfactants and Collectants

both immobilize/trap bacteria to be killed