T follicular helper cells in HIV infection

transcript

Jan van LunzenUniversity Medical Center Hamburg-Eppendorf

Heinrich-Pette-Institut for Experimental Virology & ImmunologyHamburg, Germany

Outline/Questions

Where does HIV replicate in LN? Which cells are preferentially infected? What effect/limitations does HAART have? What is the role of T follicular helper cells in HIV

infection? Are TFH cells a viral reservoir? What are the consequences of dysregulated TFH

function? Can these functions be restored?

Where does HIV replicate in lymph nodes?

Lymph Node PathologyHIV - HIV +

Stellbrink & van Lunzen, Curr Opin Infect Dis 2001

Immunopathology of LN

Tenner-Racz K, Stellbrink HJ, van Lunzen J et al., J Exp Med 1998

CD4+Ki-67+

Which cells are preferentially infected?

Infection rate of CD57+ and CD57- CD4+ T cells in PB and LN

01 2 3 5 7Patient no.

LN CD57+CD4+ T cellsLN CD57–CD4+ T cells

PBL CD57+CD4+ T cellsPBL CD57–CD4+ T cells

Ratio of the viral loads: CD57+CD4+ T cells [%]/CD57– CD4+ T cells [%]

LN: 10.5 3.3 8.0 9.5 3.0PBL: 0.3 2.2 <0.1 2.5 2.5

Hufert F, van Lunzen J et al.: AIDS 1997

What effect/limitations does HAART have?

HIV-1 RNA in LN during HAART

Tenner-Racz K, Stellbrink HJ, van Lunzen J et al., J Exp Med 1998van Lunzen J, Ruiz L et al., AIDS 1998

Day 0 Day 28

HIV-1 RNA p24 Ag

T cell proliferation in LN during HAART

0CD4+Ki-67+ CD8+Ki-67+

p < 0,0001

p < 0,0001pre-treatment (n = 30)post-treatment (n = 30)normal controls (n = 4)

van Lunzen J, et al., CROI 1999

What is the role of T follicular helper cells in HIV infection?

CD4 TFH cells B cell

MHC IITCR

IL-21 IFNγIL-4

• B cell proliferation• Antibody maturation (SHM)• Class switching (CSR)• Memory development

• Within the follicle• Express CXCR5, PD1, ICOS• Bcl6+ • IL-21 (cardinal cytokine)

Plasma cell

Memory B cellCD40L CD40

CD4 TFH cells are critical for effective antibody responses

ICOS ICOSLBcl6

SIV: Relative Accumulation of TFH in LN SIV acute SIV chronic (high % of TFH)SIV- SIV chronic (low % of TFH)

p=0.0008 p<0.0001

0 103 104 1050

CD150 Petrovas C. et al. JCI 2012

Immune activation rather than direct infection with SIV is associated with in vivo TFH accumulation

Chronic SIV (>2 months)

0 103 104 1050

p=0.0013p=0.0004

p=0.0164

SIV acute SIV chronic (high % of TFH)SIV- SIV chronic (low % of TFH)

Petrovas C. et al. JCI 2012

Accumulation of TFH is Associated with Increased Frequency of GC-B cells and titers of SIV-specific

Antibodies

PNAhighIgGlow

PNAhighIgGhigh

SIV - SIV +low % TFH

SIV +high % TFH

p=0.0286

x104 )

p=0.051

p=0.033p=0.048

SIV acuteSIV chronic (low % TFH)SIV chronic (high % TFH)

gp120 gp130 gp140 p27 p55

Petrovas C. et al. JCI 2012

High frequency of CXCR5+PD-1high CD4 T cell subset in the lymph node

Lindqvist M et al., JCI 2012

IL-21 preferentially produced by TFH cells

Expansion of TFH cells correlated with skewing of B cell subsets

GC B cells Late memory B cellsPlasma B cells

Hypersecretion of IgG was associated with BCL6 expression in TFH cells

Are TFH cells a viral reservoir?

TFH Cells and CXCR5-PD-1+ CD4 T-Cells Are Enriched in HIV-Specific CD4 T-Cells

LNMCs Intracellular staining

Aqua, CD3, CD4, CD8, CD45RA, CXCR5, PD1, IL-21, IL-2, TNF-α, IFN-γ

PTEs (Gag, Pol, Env)+α-CD28Brefeldin A

Perreau M et al JEM 2012

TFH Cells and CXCR5-PD-1+ CD4 T-Cells Are Enriched in CD4 T-Cells Containing HIV DNA

DNA extraction Taqman RT-PCR HIV-1 gag gene

TFH Cells and CXCR5-PD-1+ CD4 T-Cells Are the Most Efficient in Supporting Production of HIV

p24 detection

Anti-CD3/CD28

Collection of SNs

High viremia (>15000 HIV RNA copies/mL)

HIV Isolation from Patients with Low (<1000 HIV RNA copies/mL of plasma) in Different CD4

T-Cell Populations

TFH and CXCR5-PD-1+ but not CXCR5-PD-1- and CXCR5+PD-1- CD4 T-cells efficiently support virus isolation and production in patients with low viremia levels

Low viremia (<1000 HIV RNA copies/mL)

p24 detectionCoated CD3/28

CD8-depleted PBMCs+

Collection of SNs

What are the consequences of dysregulated TFH function?

PD-L1 expression in GC B cells

Cubas RA et al. Nature Med. 2013

PD-1 ligand and TFH proliferation, activation and cytokine secretion

Unstim. IgG beads

PD-L1 beads

P = 0.03P = 0.01

P = 0.025P = 0.009

PD-1 Triggering affects TFH function

Can these functions be restored?

P < 0.03

CXCR5hi CXCR5- CD45RA+0

10002000300040005000600070008000 CTRL

IL-21 (10ng/ml)

-IL-21 +IL21 HIV- LN

-IL-21 +IL21

P < 0.02

P < 0.03

HIV+ LN

Exogenous IL-21 enhances TFH function

-IL21 +IL21 +IL21 (10ng/ml) (40ng/ml)

P < 0.02

-IL-21 +IL21

Isotype αPD-L1/L2

HIV+ LN (Gag-Env stimulation)

Enhancing HIV-specific TFH function by interfering with PD-1/IL-21 axis

Hypothesis model

Lymph nodeB cell follicle

Germinal center

Plasma cell

Memory B cell

Germinal center B cell

HIV viremia

Summary I

• HIV-specific TFH cells are expanded in chronic infection

• Expansion of TFH cells correlated with skewing of B cell subsets in chronic HIV infection

• Hypersecretion of IgG1 was associated with BCL6 expression in TFH cells

• TFH serve as a viral reservoir and promote HIV replication

Summary II

• B memory cell responses are skewed in HIV infection

• PD-L1 is overexpressed on B cells in HIV infection and down regulates TFH function

• TFH and B cell function can be restored by anti-PD-1 and/or

exogenous II-21

• TFH cells may represent the primary obstacle for achieving functional

HIV cure

Pathogenesis Model

Vinuesa CG, JCI 2012

O. DegenS. HertlingA. HüfnerS. Schmiedel

J. Schulze zur WieschI. TothP. HartjenS. Kummer

O. DegenS. HertlingA. HüfnerS. Schmiedel

J. Schulze zur WieschI. TothP. HartjenS. Kummer

Slides and data provided by:C. Petrovas, R. Koup (VRC, NIH, USA)M. Lindqvist, H. Streeck (Ragon Inst., MGH, Boston, USA)M. Perreau, G. Pantaleo (Univ. of Lausanne, Switzerland)R. Cubas, E. Haddad (VGTI, Florida, USA)

T follicular helper cells in HIV infection

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