Art direction of award winning artwork, on cell immunity.

1. Cell surface
Binds to uniquely bacterial
lipopeptides (lipid-protein
combinations) and
to molecules called
GPI-anchored proteins
in parasites Compartment
for degrading
pathogens
Binds to lipoteichoic acid
(a component of gram-positive
bacteria)and to zymosan,
produced by fungi
Binds to LPS from
gram-negative
bacteria
Binds to single-
stranded viral RNA,
such as in HIV
Binds to single-
stranded viral RNA
Binds to so-called
CpG DNA from
bacteria or viruses
TLR1
TLR2
TLR4TLR4
TLR3
TLR7
TLR8
TLR9
THE JOBS OF TOLL-LIKE RECEPTORS
Each Toll-like receptor can detect some essential component
of a broad class of disease-causing agents, and as a
group, TLRs can apparently recognize almost every
pathogen likely to cause infections.
Different combinations appear in different
kinds of cells, where the molecules act in
pairs. Investigators have identified
10 human TLRs and know many of
the molecules they recognize
(below). The function of
TLR10 and the partners
of TLR3, 5, 7, 8 and
9 are unknown.
Binds to double-
stranded viral
RNA, such as in
West Nile virus
TLR5
TLR2
TLR6
Binds to
flagellin in the
tails of motile
bacteria
TLR4
TLR4
Mal
MyD88
Tram
Trif
Activated NF- B
NucleusCytokine genes
IL-1 and TNF-alpha:
Enhance inflammatory
responses
IL-8: Attracts neutrophils
IL-12: Promotes T cell
activity
IL-6: Promotes B cell
activity
LPS
Dendritic cell
TOLLS IN CHARGE
bacteria.HavingrecognizedLPS,pairsofTLR4ssignaltofour
moleculesinsidethecell—MyD88,Mal,TramandTrif—which,
inturn,triggermolecularinteractionsthatultimatelyactivate
amasterregulatorofinflammation(NF- B).Thisregulator
thenswitchesongenesthatencodeimmuneactivators,
includingcytokines.Thesecytokines(farright)induce
inflammationandalsohelptoswitchontheTandBcells
oftheadaptiveimmunedivision.
Toll-likereceptors(TLRs),madeby manycellsoftheinnate
system,havebeenfoundtobothorchestratetheinnateimmune
responseandplayacriticalroleintheadaptiveresponse.
TLR4,forexample,elicitsthesedefenseswhengram-negative
bacteriabegintoinvade.TLR4detectstheincursionsbybinding
tolipopolysaccharide(LPS),asugaruniquetogram-negative
Gram-negative
bacterium