resistance
 
• HIV binds to –CCR5protein on T-cells or mcrop!"es.
• #roduction o$ ne% &CCR5 ' CD(T& )ills T-cells or mcrop!"es.
• Immune system compromised.
 
 
 
 
 
• ,!y is t!e success o$ sin"le tretments s!ort-lied
• ,!y is t!e irus so irulent
• ,!y re some HIV-in$ected more resistnt to AIDS
• ,!ere did t!e irus come $rom
 
 
 
 
• Immune response
 
Defnitions
An antigen is ny substnce t!t cuses your immune system to produce ntibodies "inst it.
An epitope is t!e specifc prt o$ t!e nti"en t!t t!e immune system 0ntibodies1 2-cells1 T-cells3 reco"ni4es
2-cells
 T-cells
/crop!"e in"estin" E. coli
 
IV. A;T nd nturl selection
• A;T - loses e<ectieness in ptients oer time. Strin o$ HIV becomes resistnt.
• =t!er dru"s - proteses1 etc. t!e coc)til!
 
AIDS Tretments
• A;T - loses e<ectieness in ptients oer time. Strin o$ HIV becomes resistnt.
• =t!er dru"s - proteses1 etc. t!e coc)til!
 
AIDS Tretments
• Vccine - deelop T-cell responses to irion cot proteins 0multiple strins3
 
• A;T resembles nucleotide buildin" bloc)s o$ DA
• Reerse trnscriptse incorportes A;T in deelopin" DA
• #remture termintion o$ DA synt!esis
 
 
 
 
 
,!y A;T entully *ils
• Reerse trnscriptse is error-prone %!en it ssembles DA nd t!ere re no correction en4ymes - muttions result.
• =ne o$ t!e protein products o$ t!e DA is t!e reerse trnscriptse itsel$.
• Some mutnt rints in reerse trnscriptse $il to bind A;T.
• /utnts re $ored
 
Ho% cn HIV reerse trnscriptse become resistnt
to A;T
*i". .( RA "rooe
Red res re res o$ mino cid
substitutions t!t proide A;T resistnce 
 
HIV
AIDS Tretments
• A;T - loses e<ectieness in ptients oer time. Strin o$ HIV becomes resistnt. True o$ ny sin"le dru" tretment.
 
substituted per "enertion o$ repliction.
• Humns 0nucler DA3 - muttion $or
eery 97 "enertions 
• *lu Virus - muttion $or eery 9E 
"enertions
 
HIV eoles %it!in ptientsF
 
 
 
$rom
#!ylo"eny o$ HIV
 
 
#!ylo"eny o$ HIV
 
*uture AIDS Tretments
• >enetic en"ineerin" - ?8@ llele in CCR5 protein o$ T-cell co-receptor. turlly occurrin" llele con$ers resistnce in some !umns s irus cn’t enter cells.
 
Take-Home Message
•  Trnscription errors led to di<erent strins o$ HIV - producin" variation
•  Trits o$ di<erent strins re pssed $rom one "enertion to not!er – heritability 
• ot ll strins surie. T!ose better ble to surie nd reproduce increse in reltie number nd pss on trits. - selection 
HIV evolves, as do many diseases!
 
Multiple drug resistance is common when using antibiotics (aects bacteria
"#amples$
V%" (Vanocomycinresistant Enterococcus
 
 
Possible new way to combat antibioticresistant bacteria$
 
• Centrl Do"m - Ho% cells %or) nd reproduce.