CD4+ memory stem cells (TSCM) in pathogenic and non-

pathogenic SIV infections

Guido Silvestri, MDYerkes National Primate Research Center

Emory University School of MedicineEmory Center for AIDS Research (CFAR)

Emory Vaccine Center

The pattern of Infected CD4+ T Cell is a key determinant of AIDS pathogenesis

Damage to LN architecture &lymphoid niche

Loss of CD4 T cellhomeostasis/CD4 depletion

Chronic immune activation

Pattern of in vivoinfected cells

Features & efficacy of host immuneresponses

Size and dynamics of the “latent” reservoir

Picker . J Exp Med 2007; Letvin et al. Science 2007; Roederer et al. J Exp Med 2007; Brenchley et al. Immunity 2010; Chomont et al., Nat Med 2009; Paiardini et al. Nat Med 2011; Brenchley et al. Blood 2012; Autran et al., Clin Inf Dis 2012; Chahroudi et al., Science 2012; Saez-Cirion et al. PLoS Path 2013

Comparative AIDS Research

AIDS NO YES YES

Blood CD4 depletion Rare YES YES

Viral Load HIGH HIGH HIGH

SM RM HIV

Preserved gut & LN integrity YES NO NO

Microbial translocation NO YES YES

Chronic immune activation NO YES YES

Restricted infection of CD4+ TCM cells in SIV-infected sooty mangabeys

Level of infected cells

in vivo

Level of infected cells following in

vitro infection

Paiardini et al, Nat Med 2011

LN anatomic distribution of productively infected cells in RMs, humans, and SMs. (A) SIV/HIV vRNA+ cells/mm2 in LNs of chronically infected RMs, humans, and SMs. (B) SIV/HIV vRNA+ in B-cell follicles (C) Percentage of LN area that consists of B-cell follicles.

Brenchley et al, Blood 2012

Higher levels of Tfh infection in SIV-infected RMs and HIV-infected humans than SIV-infected SMs

Progressive Infection and AIDS

Chronic, generalized Immune Activation

How HIV and SIV infection cause AIDS:Lessons from natural SIV infections

Virus replication in central memory

CD4+ T cells

Naïve Cell Effector (short-lived, activated)

Memory cell pool

Proliferation and clonal expansion in response to antigenic stimulation

Contraction phase

Effector Memory: Resident in periphery. Able to respond quickly to re-exposure.CD62L- CCR7-

Central Memory: Resident in LNs, spleen. Able to self-renew and differentiate into Tem.CD62L+ CCR7+

Memory stem cell

antigen

Complexity of the memory CD4+ T cell pool

What is a T memory stem cell (Tscm)?• 1-3% of circulating and LN-based CD4+ and CD8+ T cells.

• Identified by classical naïve T cell markers (CD45R+CD45RO-CD62L+CCR7+CD127+CD27+CD28+), but also CD95 & CD122.

• Express more LFA-1 and CXCR3 than naïve cells, but less than TCM (and less Bcl-2 than naïve cells but more than TCM).

• Least differentiated memory subset, with high proliferative potential, and capable of self-renewal.

• Multipotent: able to generate both TCM and TEM

Gattinoni et al., Nat Med 2009; Turtle et al., Immunity 2009; Muranski et al., Immunity 2011; Gattinoni et al., Nat Med 2011; Luckey CJ, Weaver CT. Cell Stem Cell, 2012; Roederer et al., J Clin Invest, 2012

A.

TSCM

CD

8FS

C-H

CD

95

SSC

-AC

CR

7

Dea

d/14

/16/

20C

D27

CD45RA CD28CD4

CD122

FSC-A CD3FSC-A

Identification of CD4+TSCM in healthy rhesus macaques and sooty mangabeys.

E.

C.

B.

D.

A.

E.

C.

B.

D.

F.

Identification of CD4+TSCM in healthy rhesus macaques and sooty mangabeys.

B.

C.

CD4+ TSCM express levels of CXCR3 and CD11a similar to other memory CD4+ T cells subsets, and levels of Bcl-2 that are intermediate between naïve and TCM.

A.

Higher levels of CCR5 expression on CD4+TSCM of healthy RMs as compared to SMs.

C.

B.

D.

E.

F.

CD

4

SM

RM

CCR5

Selective preservation of CD4+TSCM cells during pathogenic SIV infection of RMs

B. D.

A.

p= n.s. p= n.s.

SIV infection of RMs is associated with a significant depletion of CCR5+CD4+TSCM.

A.

B.

C.

SIV infection of RMs is associated with increased proliferation of CD4+TSCM that significantly inversely correlates with the levels of CD4+TCM

A. B.

C.

D.

A.

B.

C.

Dynamics of CD4+TSCM during non-pathogenic infection of SM

D.

Robust levels of CD4+TSCM infection in vivo are observed in SIV-infected RMs but not in SIV-infected SMs

CD4+ T memory stem cells in pathogenic and non-pathogenic SIV infections

• CD4+ TSCM are numerically preserved during BOTH pathogenic and nonpathogenic SIV infections.

• However, SIV-infected RM show (i) a selective depletion of CD4+CCR5+ TSCM; and (ii) higher levels of CD4+ TSCM proliferation that correlate significantly with the level of CD4+ TCM depletion.

• Robust levels of direct virus infection of CD4+ TSCM are found only in SIV-infected RM, with 6 out of 7 SIV-infected SM showing no evidence of CD4+ TSCM infection.

CD4+ T memory stem cells in pathogenic and non-pathogenic SIV infections

RM

SMTSCM TCM

CCR5+ Ki67+

TSCM TCMSIV

AIDS

TSCM TCM

Increasing contribution of Tscm to HIV reservoir over time (M. Lichterfeld)

Lichterfeld, unpublished

Hypothesis: can reservoirs be eliminated when there is no virus in TSCM cells?

TSCM TCM TEM

ART

TSCM TCM TEM

Persistent TSCM (and TCM) reservoirs

Absence of TSCM (and TCM) reservoirs

Acknowledgments

Silvestri LabEmily CartwrightVandy Vanderford Steven BosingerAnn ChahroudiAnkita ChowdhuryMaud MavignerKiran MirTim HayesLuca MicciTayebeh HashempourCharlene WangAlex Ortiz (NIH)Nichole Klatt (UW)Diane Carnathan Paul Carnathan

SBRI -- SeattleDonald Sodora

Emory University/YerkesMirko PaiardiniColleen McGaryCynthia DerdeynJames ElseEric HunterVincent MarconiRay Schinazi

NIH/NIAID/NCIJake EstesJason BrenchleyDaniel Douek

Univ. of Pennsylvania Ron CollmanMike BettsBeatrice Hahn

Univ. of UlmFrank Kirchhoff

Ragon Institute/HMSMathias Lichterfeld

Case WesternMichael Lederman

Institut PasteurMichaela Muller-Trutwin

University of PittsburghIvona Pandrea Cristian Apetrei

Los Alamos National LabsAlan Perelson

Supported by NIH/NIAID, Emory CFAR, Georgia Research Alliance