Contribution of the immune system to HIV persistence Sharon R Lewin Director, Infectious Disease Unit, Alfred Hospital Professor, Department of Medicine, Monash University Co-head, Centre for Virology, Burnet Institute, Melbourne, Australia Towards an HIV Cure, 5 th IAS Conference, Rome, 2011

Outline  Establishing HIV latency –Where and how are resting T-cells infected? –Chemokines –Dendritic cells  Maintaining HIV latency –Homeostatic proliferation –Inflammation  Role of the adaptive immune response  Relevance to strategies for cure

establishing HIV latency

Latent infection can be established in many T cells ThymusPeripheral circulation MM M M Effector/ transitional Central memory Ag Central memory Bone marrow Chun et al., Nature 1997; 387:183; Finzi et al., Science 1997; 278:1295; Brooks et al., Nat Med 2001; 7:459 ; Chomont et al., Nat Med 2009; 15: 893; Dai et al., J Virol 2009: 83(9): ; Carter et al., Nat Med 2010; 16: 446; Wightman et al., J Infect Dis 2010; 202(11): Naïve T cellsTransitional memory Multipotent progenitor cells Latent reservoir Naive

The main reservoir is central and transitional memory T-cells Chomont et al., Nature Med 2009;15: 893

GI tract is enriched for latently infected cells Chun et al., J Infect Dis 2008; 197:714; Yukl et al., J Infect Dis 2010; 202(10): N=8, time on HAART with undetectable HIV RNA 2.8 – 12 years HIV DNA Copies per million cells

Most latently infected and productively infected cells are in lymphoid tissue North et al., J Virol 2010; 84(6): Mmu VL=17 CSF VL<50 DNARNA Lymphoid tissue GI tract+++ CNSNeg/+Neg Reproductive tissue +Neg Other+Neg RT-SHIV infection HAART =Tenofovir/emtricitabine/efavirenz

Size of HIV Reservoir correlates with activated CD8+ T cells (in Sigmoid Colon) Seth et al., Mucosal Immunology 2008:1:

What is unique about these tissue sites?  Ongoing replication due to –Poor penetration of drugs? –Localised sites of inflammation?  Unique long-lived cells such as macrophages or DCs allowing for cell-cell transmission?  Infection of resting cells?

Unactivated resting cells Resting CD4+ T-cell Ex vivo tissue blocks Eckstein et al, Immunity 2001; 15: 671; Kreisberg et al., J Exp Med 2006; 203:865; Infection of resting T-cells in vitro chemokines In vitro Saleh et al., Blood 2007; 110:416; Cameron et al., Proc Natl Acad Sci 2010 epub Sept 18

Multiple chemokines can induce latent HIV infection in resting CD4+ T cells. Cameron et al., Proc Natl Acad Sci 2010; 107(39):

Chemokine receptor ligation activates cofilin and actin polymerisation CXCR4 + gp120 CCR7 + CCL19 Yoder et al Cell 2008 Cameron et al PNAS 2010

Chemokine signalling pathways PI3K PI3K

Inhibition of Erk1/2, Jnk and NF-kB eliminates integration (ALu-LTR) SC-514 Bay SP SB PD CCL19+DMSO JNKERK NF  B P38 Saleh et al., 5 th IAS Conference, Rome, 2011

Unactivated resting cells Resting CD4+ T-cell Ex vivo tissue blocks Eckstein et al, Immunity 2001; 15: 671; Kreisberg et al., J Exp Med 2006; 203:865; Infection of resting T-cells in vitro chemokines In vitro Saleh et al., Blood 2007; 110:416; Cameron et al., Proc Natl Acad Sci 2010 epub Sept 18 Dendritic cells

Dendritic cells facilitate latent HIV infection Evans et al., unpublished

maintenance of HIV latency

What is the fate of a latently infected cell? Negative regulators differentiation EM activation Homeostatic proliferation

Number of latently infected cells is correlated with proliferation: role of IL-7 Chomont et al., Nat Med 2009

IL-7 increases proliferation leading to expansion of HIV DNA in vivo HIV infected subjects under suppressive HAART received IL-7 injections (ACTG5214, blind study). Vandergreeten 6 th IAS conference on HIV Pathogenesis, Treatment and Prevention, Rome, 2011 Day 0Day p=0.03 Int HIV DNA per mL of blood Day 0Day Int HIV DNA per 10 6 CD4 T cells

What is the fate of a latently infected cell? Negative regulators differentiation EM activation Homeostatic proliferation

PD-1 hi cells are enriched for latentlly infected cells Da Fonesca et al., HIV Reservoir Workshop, Vienna, July 2010 Donor ADonor BDonor C Mock a-PD-1 blocking Ab Isotype control p24 (pg/mL) Chomont et al., Nature Med 2009;15: 893

What is the fate of a latently infected cell? Negative regulators differentiation EM activation Homeostatic proliferation IL-15

role of the adaptive immune response

Inverse relationship between HIV- specific CD4+ T-cells and HIV DNA Martinez et al., J Infect Dis 2001; 191:2053–63 N=66; long term non progressors, no ARV

HLA type influences size and distribution of latently infected cells Descours; Avettand-Fenoel Submitted

Summary  Latency can be established in multiple T-cell subsets  High concentration of latently infected cells in tissue including GI tract and lymphoid tissue  Chemokines and dendritic cells play a key role in establishing latency in resting T-cells  Maintenance of latency can occur by –Homeostatic proliferation (IL-7) –Negative regulators of T-cell activation (PD1)  Adaptive immune response likely important

What is the fate of a latently infected cell? Negative regulators differentiation EM activation Homeostatic proliferation Anti-IL7Anti-PD-1 Auranofin IL-15 Chemokine antagonists vaccination minocycline

Acknowledgements  Department of Medicine, Monash University, Melbourne –Paul Cameron –Suha Saleh –Vanessa Evans –Nitasha Kumar –Ajantha Solomon –Georgina Sallman –Fiona Wightman  Westmead Millenium Research Institute, Sydney –Tony Cunningham –Andrew Harman  VGTI Florida, Port St Lucie, FL –Rafick Sekaly –Elias Haddad –Genevieve Boucher –Nicolas Chomont  Hopital Pitie Salpatriere, Paris –Brigitte Autran –Benjamin Descours