ENDOTOXINS
Endotoxinsareapartoftheoutermembraneofgramnegativebacteria.Thisisamembrane
outsidethepeptidoglycanlayerandconsistsoflipoproteins,phospholipids,and
lipopolysaccharides.Thelipidportionofthelipopolysaccharide,calledlipidA,istheendotoxin.
Endotoxinsarelipopolysaccharidesinsteadofproteins.Theyproducetheireffectsafterthegram
negativebacteriadieandtheircellwallsundergolysis.Someantibioticsusedagainstgram
negativebacteriacauselysisofthecellwallandmaytemporarilymakesymptomsworse.All
endotoxinsproduceaboutthesamesignsandsymptoms,althoughthesemaybemoreseverewith
someorganismsthatwithothers.Theyincludechills,fever,weakness,aching,andinextreme
casesshockandevendeath.Theydothisbystimulatingmacrophagestoreleaseexcessamounts
ofcytokines.Endotoxinscancontributetomiscarriages.
Endotoxinscanactivatebloodclottingproteins,causingtheformationofmanysmallbloodclots
thatblockcapillaries.Tissuesthusdeprivedoftheirbloodsupplydie.Thisiscalleddisseminated
intravascularclotting(DIC).
Feveriscausedinthefollowingway:
1.Gramnegativebacteriaarephagocytized
2.Astheyarebrokendowninsidethephagocyticcell,thelipopolysaccharidesoftheouter
membranearereleased.Thiscausesmacrophagestoproduceinterleukin1.
3.Interleukin1iscarriedtothehypothalamusofthebrain,wherethetemperaturecontrol
mechanismforthebodyislocated.
4.IL1causesthehypothalamustoreleaseprostaglandinswhichresetthebodysthermostat
toahighertemperature,sowebegintorunfever.
5.Aspirin,Tylenol,etc.inhibitthereleaseoftheprostaglandins,whichreducesthefever.