1. Catherine K. Koofhethile 21st IAS 2016 18-22 July,2016 Durban, SA
CD8+ T cell breadth and ex vivo virus inhibition capacity distinguish between viremic controllers with and without protective HLA class I alleles
Catherine K. Koofhethile
21st IAS 2016
18-22 July,2016
Durban, SA

2. The impact of HLA on HIV disease progression
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
B*57
p <
p =
p =
B*81:01
B*58:01
A*74:01
Mechanism of control?
Protective
Non protective
B*58:02
Kiepiela et al,
Nature, 2004
B*18:01
p <
p =

3. Gaps in knowledge ? responsible for control and loss of control?
baseline non-controllers ?
Failing VC (fVC)
Viremic controllers (VC)
What are the immunological and virological events
responsible for control and loss of control?

4. Study design and methods in brief
Protective HLA alleles: HLA- B*57, B*58:01, B*81:01, A*74:01
ARV naïve; at least 2 yr follow up.
VL, CD4 count, HLA typing
Immune responses – ELISPOT assay; OLP/optimal peptides covering whole HIV proteome.
Sequencing of Gag (bulk) – molecular methods
Ex vivo Viral inhibition assay
SK COHORT
n = 453
With protective HLA alleles
n = 133
Baseline non-controllers (bNC)
VL >100,000 RNA copies/ml
(enrollment)
n = 15
Baseline viremic controller (bVC+)
VL< 2,000 RNA copies/ml
n = 20
Without protective HLA alleles
n = 320
VL > 100,000 RNA copies/ml
n = 25
Baseline viremic controller (bVC)
VL< 2,000 RNA copies/ml (enrollment)
n = 10
7 VC+
7 fVC+
6 VC-

5. Clinical characteristics of study participants at enrollment
Groups
Protective HLA alleles +/- n
Median years of follow up (IQR)
Median viral load (HIV RNA copies/ml) (IQR)
Median CD4 count (cells/mm3)(IQR)
Baseline VC + 20
5 (4 - 6)
487
(283 – 1,252)
509
(459 – 684)
Baseline non-controllers 15
4 (3 - 6)
156,000 (118,000 – 192,000)
329 (257 – 377) - 10
613 (399 – 1,213)
669 (550 – 865) 25
3 ( )
209,000 (132,000 – 330,500)
373 (260 – 467)
Protective HLA alleles: HLAs B*57, B*58:01, B*81:01 and A*74:01

6. CD8+ T cell responses to Gag are associated with lower VL in individuals with protective HLA alleles
OLP stim.

7. There is loss of virologic control amongst baseline viremic controllers with protective HLA alleles
VC+ n=7
fVC+ n=7
VC- n=6

8. Loss of CD8+ T cell breadth is associated with loss of viral control
Optimal peptide stim.

9. Viral escape and non-escape mechanisms of loss of CTL loss
fVC+
Baseline
Post loss
timepoint
DIAGTTSTLQEQIAWMTSNP
DIAGTTSNLQEQITWMTSNP
200
B*57-TW10 p24
SCENARIO 1
Baseline
Post loss
timepoint
TLRAEQATQDVKNWMTDLL
300
B*57-QW9 p24
SCENARIO 2
What remains unknown is the loss of CD8+ T cell responses in the absence of escape

10. CD8+ T cell ex vivo virus inhibition assay
HIV
CD4+ T-cells
Black Box +
Autologous
CD8+ T-cells
Co-culture infected CD4 T-cells with CD8+ T cells at E:T ratio 1:1
Inhibition of HIV
replication measured by
p24 in supernatants

11. Overall inhibition- VC+ display enhanced ex vivo CD8+ T cell inhibitory capacity

12. Main findings Baseline viremic controllers (bVC)
with protective HLA alleles (+) n=14
Broad Gag CTL responses
Good virus inhibition capacity
Baseline viremic controllers (bVC)
without protective HLA alleles (-) n=6
Limited Gag CTL responses,
Limited virus inhibition capacity
VC (-) n=6
Maintain limited CTL
responses
CTLs limited ability to
inhibit viral replication
VC (+) n=7
Maintain broad Gag CTLS
CTLs maintained ability to
Inhibit viral replication.
Failing VC (+) n=7
Lost CTL responses
CTLs had limited ability
to inhibit viral replication
Loss of some CTL responses  escape
Mechanism of control- CTL
dependent
Mechanism of control- Non CTL
Loss of some CTL responses NOT due to escape -> ??????
CD4? Virus? Innate immunity?
Koofhethile et al. JVI 2016

13. Acknowledgements Harvard/MGH HPP, UKZN Prof. Bruce Walker
Elana Stampouloglou
University of Oxford
Prof. Philip Goulder
AIDS Research Institute IrsiCaixa, Spain
Dr Julia Prado
Funding
Organisation for Women in science for the developing world
NIH, Ragon Institute of MGH, MIT and Harvard University.
HPP, UKZN
Prof. Thumbi Ndung’u
Dr Christina Thobakgale
Dr Zaza Ndhlovu
HPP team
Sinikithemba study team
Study participants
CAPRISA
Nonhlanhla Yende