HIV-1 infection decreases CD127 and PD1 expression on duodenal

CD8+T cells

Liliana Belmonte, PhDAcademia Nacional de Medicina

Buenos Aires, Argentina

Background

The GI tract is a major site of HIV replication and pathogenesis,

regardless of the specific tissue site of viral entry.

Persistence of HIV in the duodenal mucosa even when effective

therapy suppresses HIV-RNA in blood to undetectable levels, has

been demonstrated by previous studies from our group.

(Belmonte L et al, AIDS 2007;21(15):2106-8).

Chronic HIV infection often results in ineffective

CD8 T-cell responses. However the mechanisms

triggered by persisting virus infection and their

impact on CD8 T-cell effector functions and tissue

distribution, remain unknown.

Specific Aim

To analyse the quality of duodenal CD8 T cells in

chronically HIV-infected patients.

Distal Duodenal biopsies

26 patients with chronic HIV-1 infection under HAART

13 HIV-1 seronegative individuals were included as control (C)

We analyzed the presence of HIV-DNA in

the duodenal tissue. A biopsybiopsy was labeled was labeled

as as “HIV +”“HIV +” if HIV-DNA was detected by if HIV-DNA was detected by

standard PCR standard PCR

(using the primers SK145 and SKCC1B to define (using the primers SK145 and SKCC1B to define

a sequence of 155 nucleotides within the highly a sequence of 155 nucleotides within the highly

conserved region of the HIV-1 gag gene)conserved region of the HIV-1 gag gene)

Distal Duodenal biopsies

26 patients with chronic HIV-1 infection under HAART

13 HIV-1 seronegative individuals were included as control (C)

Endoscopic material were disrupted

mechanically and a cell suspension was

prepared. Expression of CD4, CD8, CD27,

CD28, CD45RO, CD45RA, CCR7, CD127,

PD-1 (BD) was analysed by flow cytometry

(FacScan, BD).

We analyzed the presence of HIV-DNA in

the duodenal tissue. A biopsy biopsy was labeled was labeled

as as “HIV +”“HIV +” if HIV-DNA was detected by if HIV-DNA was detected by

standard PCR standard PCR

(using the primers SK145 and SKCC1B to define (using the primers SK145 and SKCC1B to define

a sequence of 155 nucleotides within the highly a sequence of 155 nucleotides within the highly

conserved region of the HIV-1 gag gene)conserved region of the HIV-1 gag gene)

Percentages of CD4 and CD8 T cells in the duodenal mucosa

R1R1 R1R1

HI V+ patient Control

0

10

20

ControlsHIV-1+ patients

Du

od

enal

CD

4+ T

cel

ls(%

)

p= 0.0013

0

25

50

75

HIV-1+ patients Controls

Du

od

enal

CD

8+ T

cel

ls(%

)

Duodenal Memory CD8 T cell differentiation (CD45RA, CCR7 expression)

CD8+CD45RA+

CCR7+

CD8+CD45RA-CCR7+

CD8+CD45RA-

CCR7-

CD8+CD45RA+

CCR7-

Precursor memory T cells

Terminally differentiated

cells

Pre-terminallydifferentiated

cells

5.6 5.6 ±±2 %2 %89 89 ±±3 %3 %ControlsControls

6.6 6.6 ±±3 %3 %80 80 ±±6 %6 %HI V+ HI V+ patientspatients

5.6 5.6 ±±2 %2 %89 89 ±±3 %3 %ControlsControls

6.6 6.6 ±±3 %3 %80 80 ±±6 %6 %HI V+ HI V+ patientspatients

p= nsp= ns p= nsp= ns

CD45RA- CCR7- CD45RA+ CCR7-CD45RA- CCR7- CD45RA+ CCR7-

Duodenal Memory CD8 T cell differentiation (CD27, CD28 expression)

CD8+CD28+CD27+

CD8+CD28-CD27+

CD8+CD28-CD27-

Late effector cells

IntermediateDifferentiated

cells

Early Differentiated

cells

HIV-1 + patients

HIV+ biopsies (n=10)

HIV- biopsies (n=6)

Controls

(n=12)

Early

Differentiated cells

(CD28+,CD27+) (%)

12 ± 5 10 ± 4 12 ± 5

Late

Effector cells

(CD28-, CD27-) (%)

39 ± 6

61 ± 8

23 ± 4

*p=0.0003

p=NS

* p=0.04

p=NS

p=NS

MeanSEM

High Programmed-death 1 (PD-1) expression on duodenal CD8 T cells from

HIV+ patients

HIV+biopsies

HIV-biopsies Controls

0.0

2.5

5.0

7.5

10.0D

uode

nal C

D8+

, PD

1+ce

lls (

%)

p=0.0017

p=0.04p=ns

Decreased CD127 high (IL7R) expression on duodenal CD8+ T cells from HIV+ patients

0.0

2.5

5.0

7.5

10.0

p<0.0001

p=0.01

Du

od

enal

CD

127

hig

h+

,C

D8+

(%

)

HIV+biopsies

HIV-biopsies

Controls

p=ns

Conclusions

Our results demonstrate an accumulation of the pre-terminally

differentiated subset of memory cells. This findings could be due to

a depletion of terminally differentiated CD8 T cells and/or lack of

CD4 helper activity.

Conclusions

The pool of late effector CD8 T cells (CD27-, CD28-) was higher in

HIV+ patients than in C. However, in HIV+ patients with HIV+ biopsies

this value was lower than in those with HIV- biopsies, suggesting that

continuous Ag exposure leads to late effector cell loss.

Our results demonstrate an accumulation of the pre-terminally

differentiated subset of memory cells. This findings could be due to

a depletion of terminally differentiated CD8 T cells and/or lack of

CD4 helper activity.

Conclusions

PD-1 was significantly up-regulated on duodenal CD8 T cells in HIV+

patients. Functional impairment (exhaustion) could lead to ineffective

viral control, since in the biopsies where HIV persisted, the % of

exhausted cells tended to be higher.

Conclusions

PD-1 was significantly up-regulated on duodenal CD8 T cells in HIV+

patients. Functional impairment (exhaustion) could lead to ineffective

viral control, since in the biopsies where HIV persisted, the % of

exhausted cells tended to be higher.

HIV infection suppressed CD127high expression on duodenal CD8 T

lymphocytes. The proportion of CD127-expressing cells was slightly

lower in the biopsies where HIV persisted and this could be related to T

cell exhaustion. These data support further the concept that HIV

infection can alter memory CD8 differentiation.

AknowledgementsAknowledgements

Gastroenterology Unit- City Hospital “Juan A Fernandez” Alberto Zalar, MD Norma Correa, MD

Infectious Diseases Unit-City Hospital “Juan A Fernandez” Pedro Cahn, MD, PhD Maria Inés Figueroa, MD

Laboratory of Immunology- Academia Nacional de Medicina Ana Coraglia, PhD st Maria Marta de E de Bracco, PhD

ANPCyT-MinCyT and Roemmers Foundation for financial support