Dissecting T cell responsiveness to C- cytokines in HIV-infected subjects

Dissecting T cell responsiveness to C-cytokines in HIV-infected subjects

Catherine Riou

NICD/PHRU

Johannesburg, South Africa

CAPTNetworkAfrican Led,Canadian Enabled

NICD

Background

• Cytokines play a key role in the proliferation, differentiation, function and survival of T cells.

• HIV-specific cells are defective in their ability to proliferate and to produce cytokines.

Less is known about T cell responsiveness to cytokine in HIV + individuals.

How different T cell subsets respond to cytokines?

Is cytokine responsiveness impaired in HIV-infected individuals?

Do specific profiles of T cells associate with viral control?

AIMS

- Study the phosphorylation profiles of different T-cell subsets in response to exogenous c-cytokine engagement

IL-2 : T cell proliferation and activated induced cell death (AICD) IL-7 and IL-15 : maintenance of T cells (IL-15 favours the cell proliferation and IL-7 rather favours cell survival).

- Study the phosphorylation profiles of HIV- and CMV-specific CD8+ T cells in response to exogenous c- cytokine triggering.

Study Subjects

HIV- HIV+

Age (p=NS) Median (range) 35 (27-60) 35 (21-57)

CD4 count (p<0.0001) Median (range) 953 (324-2119) 388 (137-1289)

Viral Load Median (range) NA 27900 (432-750,000)

CMV positive (p=NS) % 96 96

Female % 34 66

HIV+ individuals present different rate of disease progression

102 103 104 105 1060

100

200

300

400

500

600

700

800800

1200

Viral load

r=-0.57p<0.0001

200

400

18 HIV-discordant couples

Studied Pathways

c-Cytokine triggering(IL-2, IL7, IL15)

ProliferationSurvival

0 102 103 104 105

<660/20 APC OR Alexa 647-A>

0

20

40

60

80

100

0.87

0 102 103 104 105

<660/20 APC OR Alexa 647-A>

0

20

40

60

80

30.9

Phospho-Stat5

Cel

l co

un

t

No stimulation

+IL-7 (15min)

Studied T cell Subsets

Naïve and Memory subsets

Naïve CentralMemory

TransitionalMemory

EffectorMemory Effectors

proliferation

Survival

Differentiation lineage

Burgers, Riou et al. JI. 2009

Maturation

0

25

50

75

100

N CM TM EM Eff

CD8+

Ph

os

ph

o S

tat-

5 (%

)

IL-7

0

25

50

75

100

N CM TM EM Eff N CM TM EM Eff

CD8+ CD4+

IL-2

0

25

50

75

100

N CM TM EM Eff N CM TM EM Eff

CD8+ CD4+

IL-15

N CM TM EM Eff

CD4+

Ph

osp

ho

Sta

t-5

(%)

Ph

osp

ho

Sta

t-5

(%)

Cytokine responsiveness in HIV- individuals

-T cells responsiveness to cytokines decreases with Cell differentiation (CM>TM>EM>Eff) in both CD4 and CD8 compartments.

- Naïve cells are characterized by a diminished responsiveness to IL-15 and IL-2

HIV uninfected individuals

Cytokine responsiveness in HIV+ vs HIV- individuals

CD8+ cells

NHIV

pS

TA

T-5

(%

)HIV+HIV-

0

25

50

75

100

- + - + - + - + - +CM TM EM Eff

No major differences in cytokine responsiveness between HIV+ and HIV- in any CD8+ T cells subsets

IL-7

Relationship between Receptor Expression and Cell Responsiveness

- + - + - + - + - +N CM TM EM Eff

*** ***

*

CD

12

7 e

xp

res

sio

n (

%)

HIV+HIV-

IL-7 Receptor expression levels

0

25

50

75

100

0.001 0.01 0.1 10

10

20

30

40

50

Concentration IL-7 (ng/ml)IL-7 concentration (ng/ml)

pS

tat-

5 e

xp

res

sio

n (

%)

Dose response IL-7

IL-7 Receptor levels do not reflect responsiveness in HIV-infected individuals.

0 20 40 60 80 1000

10

20

30

40

50

60

70

80HIV-

HIV+

CD8 EM 127+ %

p=0.0002 (***)p=NS

IL7R expression (%)

pS

tat-

5 e

xp

res

sio

n (

%)

Correlation % IL7-R and Stat-5 response

Dissociation of Receptor expression and IL-7 responsiveness in HIV+ Individuals.

82% 64%

Total CD8+ TET+ cells

IL-7

81% 61%

Total CD8+ TET+ cells

CMV (A2-pp65) HIV (A2-Gag)

0.9%

TET-PE

SS

C

T cell responsiveness to cytokines in Antigen-specific T cells

pSTAT-5 pSTAT-5

CD8 tot CMV spe HIV spe3540455055606570758085

CD8Total

CMVspe

HIVspe

p-S

tat5

(%

)

HIV and CMV Co-infected donors with undetectable Viral Load

We can speculate that HIV-specific cells in

controllers present a Early-Differentiated

phenotype according to their high responsiveness

to IL-7.

Which HIV-specific T cells subsets associate

with viral control ?

Which HIV-specific CD8+ T cells subsets associate with viral control?

Bu

rge

rs,

Rio

u e

t al

. 20

09

0 103 104 105

<APC-A>: PHOSPHO

0

20

40

60

80

100

Viral set point at 12 months

p=0.0009r = 0.58

% Effector Memory

102 103 104 105 1060

5

10

15

20

25

30

35

40

45

Accumulation of Early differentiated cells at 6 months correlate with low viral sets point at 12 months

P-Stat-5

+IL-7

% of Central Memory

102 103 104 105 1060

3

6

9

12

15

2025303540

p=0.002r = -0.54

-HIV infection does not to alter the capacity of T cells to respond to IL-2, IL-7 and IL-15.

-T cell memory subsets show distinct phosphorylation profiles in response to exogenous cytokine stimulation: cells heading for terminal memory differentiation lose the ability to respond to IL-7.

-EM CD8+ T cells positively correlate with high viraemia

-Maintenance of CM early differentiated CD8+ T cells associates with viral control.

Conclusions

Hypothesis: early differentiated T cells capable of responding to cytokine signaling are important for controlling HIV in the

absence of ARV therapy

Potential model for Viral Control

Low Viral set point

CMEM

High responsiveness to cytokinesGood proliferation capacitiesGood survival abilities

High Viral set point

CMEM

Low responsiveness to cytokines Low proliferation capacities Low survival abilities

Desirable from a vaccine

CAPTNetworkAfrican Led,Canadian Enabled

NICD

Netty MalatsiPr. Clive Gray

Bara Clinical TeamDr. Guy de Bruyn

Pr. R.P. Sekaly

University of Montreal

PHRU, Soweto

NICD, Johannesburg

CAPTCHAVI

Funders