Innate Immune System

innate responses

destruction of microbes, activation of phagocytes, and inflammation

PRR-PAMP

causes phagocytosis, activation of cells, cytokine secretion, and inflammation

toll-like receptors

PRRs that are membrane associated and cause a signal cascade

TLR 2

the receptor that responds to peptidoglycan

TLR 4

the receptor that responds to LPS (endotoxin)

scavenger receptors

PRRs that detect modified lipoproteins, phagocytose bacteria, and clear apoptotic cells

opsonin

any substance that enhances phagocytosis of a cell or particle

NOD-like receptors

cytosolic receptors that detect a variety of PAMPs and activate caspase-1 which activates IL-1Beta; inflammasomes

IL-1Beta

an important inflammatory cytokine

markers of abnormal self

reduction of surface markers

expression of stress markers

can be detected by some PRRs

can be detected by KARs on NK cells

defensin

a molecule that causes pores in bacteria

lysozyme

a molecule that breaks down peptidoglycan at the Beta 1-4 linkage

alternative pathway

a complement activation pathway that is activated by C3b binding to a microbe and ends in a MAC attack

B and D

factors that continue the alternative pathway

H and I

factors that inhibit the alternative pathway

C3 convertase

the enzyme that acts on C3 because a microbe is present

C5 convertase

the enzyme that breaks C5 into C5a and C5b

MAC attack

multiple C9 insertions that result in pore formation and lead to lysis

MBL pathway

the complement pathway that is activated by MBL binding to mannose on certain microbes and feeds into the lytic pathway where C3 convertase typically is

MASP

the enzyme that activates complement in the MBL pathway and takes the place of C3b

C3b

the major opsonin of the complement system

anaphylotoxin

a molecule that is a chemoattractant to phagocytes (e.g. C3a, C4a, C5a)

cytokine

a protein secreted by a variety of cells that change the behavior of other cells

chemokines

a subgroup of cytokines that acts as a chemoattractant to leukocytes

Type I interferons

INF-alpha and INF-beta

interferons

molecules that stimulate cells into an anti-viral state, activate NK and NKT cells, upregulate MICA and MICB, and cause cells to resist viral replication

IL-1Beta and TNF alpha

cytokines that make blood vessels more permeable (inflammation)

IL-6

the cytokine that induces fat and muscle cells to metabolize, creating fever

CXCL8

a chemokine that recruits neutrophils

IL-12

a chemokine that recruits and activates NK cells

TNF alpha associated diseases

RA, psoriasis, Crohn’s, colitis

antibodies and decoy receptors

methods of blocking TNF alpha

phagocytosis

cellular eating that is mediated by cell surface receptors and clathrin-coated pits

macropinocytosis

sampling of the surrounding fluid that is independent of clathrin

inflammation pros

clears microbes and initiates wound healing

inflammation cons

possible damage to tissue and fatality

phagocytosis steps

receptor mediation

endocytosis through pseudopodia

phagosomes fuse with lysosomes

change occurs in phagocyte