Differential impact of IL-7 and IL-15 on HIV reservoir persistence

Claire Vandergeeten, PhD

IAS, Rome, July 18th 2011

• HIV persists in memory T cells (Chun, Proc Natl Acad Sci U S A, 1997; Wong, Science, 1997; Finzi, Nat Med, 1999)

• Persistence by homeostatic proliferation (Chomont, Nat Med, 2009)

• IL-7 and IL-15 are involved in the maintenance of memory CD4 T-cells (Kondrack, J Exp Med, 2003; Lenz, Proc Natl Acad Sci U S A, 2004)

• What are the role of IL-7 and IL-15 on HIV persistence?

Why are we interested in the study of the role of IL-7 and IL-15 on HIV reservoir persistence?

Impact of IL-7 therapy on the HIV reservoir size (1)

• ACTG5214 clinical trial (10 virally suppressed subjects)

• A single injection of 4 rhIL-7 doses (3, 10, 30 or 60 µg/kg) or placebo

0 10 20 300

25

50

75

IL-7

placebo

% C

D4+

Ki6

7+

IL-7 induces proliferation of CD4 T cells

Day 0 Day 4 Day 28IL-7

injection

PBMCs PBMCsPBMCs

Days

Impact of IL-7 therapy on the HIV reservoir size (2)

IL-7 does not increase the frequency of reservoir cells within the CD4 compartmentIL-7 increases the absolute number of CD4 T cells harboring HIV DNA

Day 0 Day 280

200

400

600

800

p=0.03

Int H

IV D

NA

per m

L of

blo

od

Day 0 Day 280

500

1000

1500

2000

Int H

IV D

NA

per 1

06 CD

4 T

cells

• Integrated HIV DNA was measured by a semi-nested Real Time PCR (Alu PCR)

Gen

etic

div

ersi

ty (%

)

0

1

2

3

4

0

2

4

6

8

Baseline CD3/CD28

Day 0 Day 8

Baseline CD3/CD28

Day 0 Day 8

Gen

etic

div

ersi

ty (%

)

P = 0.0002

P = NS

P = NS

P < 0.0001

P = NS

P = NS

IL-7 1ng ml–1

IL-7 10ng ml–1

IL-7 1ng ml–1

IL-7 10ng ml–1

Sub

ject

1

Sub

ject

2

Impact of IL-7 on HIV reservoir diversity

• CD4 T-cells from successfully treated subjects were stimulated with IL-7 (1 or 10 ng/mL)

• HIV reservoir diversity was evaluated by sequence of the env gene after 8 days.

IL-7 maintains HIV reservoir diversity in vitro

Although IL-7 restores CD4 T cell count through cell proliferation (Sereti, Blood, 2009; Levy, JCI, 2009) it also increases the number of CD4 T cells harboring HIV integrated DNA

IL-15 is another c cytokine involved in the maintenance of T cell memory

Evaluation of the effect of IL-15 and IL-7 on:

• Viability of CD4 T cells

• Activation and proliferation of CD4 T cells

• Viral production from latently infected CD4 T cells

• CD4 T-cells were stimulated with IL-7 or IL-15 at 10 ng/mL. • Viability was measured by flow cytometry after 6 days.

Impact of IL-7 and IL-15 on viability of CD4 T cells

Both IL-7 and IL-15 promote survival of CD4 T cells

NS IL-7 10 ng/mL

IL-15 10 ng/mL

80

85

90

95

100

% v

iabi

lity

Impact of IL-7 and IL-15 on activation and proliferation of CD4 T cells

• CD4 T-cells were stimulated with IL-7 or IL-15 at 10 ng/mL. • Proliferation and activation were measured by flow cytometry after 6 days.

IL-7 induces higher levels of cell proliferation than IL-15IL-7 and IL-15 induce similar levels of activation markers

% C

D4+

Ki6

7+

% C

D4+

HLA

-DR

+

% C

D4+

PD

-1+

NS IL-7 10 ng/mL

IL-15 10 ng/mL

0

2

4

6

8

NS IL-7 10 ng/mL

IL-15 10 ng/mL

0

5

10

15

20

p=0.004

NS IL-7 10 ng/mL

IL-15 10 ng/mL

0

3

6

9

12

IL-15 reactivates HIV production from latently infected cells in vitro

IL-15 induced viral production in latently infected cells very efficiently when compared to IL-7 ( 4 fold increase)

Impact of IL-7 and IL-15 on HIV reservoir reactivation

#1#2#3#4#5#6

• CD4 T-cells from successfully treated subjects were stimulated with IL-7 or IL-15 at 10 ng/mL in the presence of ARV.

• Viral production was measured by a sensitive real time PCR after 6 days.

Vira

l RN

A co

py

p = 0.04

NS CD3/CD28

IL-7 10 ng/mL

IL-15 10 ng/mL

0

3000

6000

9000

12000

Conclusion

• IL-7 increases the absolute number of CD4 T cells harboring integrated HIV DNA in vivo and maintain the genetic diversity of the reservoir in vitro

• IL-7 and IL-15 induce proliferation, activation and survival of CD4 T cells

• IL-15 induce viral production very efficiently when compared to IL-7

IL-15 should be considered as a possible candidate to achieve HIV eradication

IL-15IL-7

ARV

CD4 T cells

Integrated HIV DNA

HIV viral particles

Differential impact of IL-7 and IL-15 on HIV reservoir

Acknowledgments

VGTI Florida:Nicolas ChomontRafick-Pierre SekalySandrina DaFonsecaRémi Fromentin

ACTG5214 study :Michael LedermanIrini Sereti