SLIDE 1
HIV-1- and Influenza –cross-reactive CTL
Thom as Harrer
I nfectious Diseases Unit Departm ent of Medicine 3
SLIDE 2 Detection of HIV-1-specific CTL in HIV-1-exposed Seronegative Subjects
(Roland-Jones et al., 1998)
potential mechanisms:
- abortive infection
- immunization by infected cells without infection
- induction of cross-reactive CTL by other pathogens expressing
epitopes with homology to HIV-1 epitopes
CTL
HLA TCR
SLIDE 3 Cross-reactivity between the HIV-1-p17-epitope SLYNTVATL (SL9) and the influenza M1 matrix protein epitope GILGFVFTL (GL9)
SL9 and GL9 have been published as immunodominant HLA-A2-restricted CTL epitopes in HIV-1-infection and in influenza, respectively
Acierno et al. showed GL9-cross-reactive CTL in HIV-1-infected patients and SL9-cross-reactive CTL in influenza patients.
Acierno PM et al. Cross-reactivity between HLA-A2-restricted FLU-M1: 58-66 and HIV p17 GAG: 77-85 epitopes in HIV- infected and uninfected individuals. J Transl Med. Aug 14 2003; 1(1): 3.
CTL
GILGFVFTL Influenza IMP GL9
CTL
SLYNTVATL HIV-1 p17 SL9
SLIDE 4
S L Y N T V A T L
T-cell receptor cross-recognition: potential mechanism
CTL
G I L G F V T L F G I L G F V T L F
a ß
CTL
a ß
CTL
a ß TCR-Peptide interaction: Same TCR-interface different TCR-interface
SLIDE 5 Do SL9/ GL9-cross-reactive CTL
contribute to resistance to HIV-1 infection ?
- What is the prevalence in HIV-1 negative subjects ?
- What is the prevalence in HIV-1 exposed seronegatives ?
-
influence the course of HIV-1 infection ?
- Hypothesis:
- pre-existing SL9/GL9 cross-reactive CTL could exert a rapid antiviral response and lower viral
setpoints leading to a better course of infection
SLIDE 6
Generation of GL9- and SL9-specific CTL
Stimulation of 5 Million PBMC each with SL9- and
GL9-peptides
Testing of outgrowing cells for recognition of SL9 and
GL9 in γ-IFN ELISPOT assays
SLIDE 7
Recognition of SL9 and GL9 in HLA-A2+ HIV-1-negative patients
Only 2/18 HIV-1-negative blood donors generated CTL against GL9 which did not cross-react to SL9. No SL9-CTL.
Only 1/7 exposed seronegative patients generated both GL9- and SL9- specific CTL, however, without SL9/GL9-cross-reaction
In addition, freshly isolated PBMC from another exposed seronegative patient showed GL9- and SL9-specific CTL responses, however, no proof of cross-reactivity as no CTL lines could be generated
SLIDE 8 Recognition of SL9 and GL9 in HLA-A2+ HIV-1-negative patients
GL9-specific CTL were detected only in a minority of HLA-A2-positive healthy blood donors
potential reasons
- good vaccination status prevents influenza infection and induction of CTL
- low precursor frequency of influenza – specific CTL in healthy subjects
SL9-specific CTL in 2/ 8 exposed seronegatives, but no cross-reaction to GL9.
This argues against a major role of GL9/ SL9-cross-reactive CTL in resistance against HIV-1 infection
SLIDE 9
Recognition of SL9 and GL9 in HLA-A2+ HIV-1-infected patients
175 HIV-1-infected subjects, among them 145 on ART
Detection of:
SL9-specific CTL in
92 patients (52.6% )
GL9-specific CTL in
94 patients (53.7% )
SL9- and GL9-specific CTL in
71 patients (40.6% )
CTL against SL9 and/ or GL9 in 115 patients (65.7% )
SLIDE 10 Cross-recognition of SL9- and GL9-specific CTL
60 of 92 SL9-specific CTL lines (65.2% ) recognized GL9.
62 of 94 GL9-specific CTL lines (66% ) recognized SL9.
cross-reactions between GL9 and SL9 observed in 75 of 175 patients (42.9% ).
SLIDE 11 50 100 150 200 250 300 + 20 µg/ml + 10 µg/ml + 1 µg/ml + 100 ng/ml + 10 ng/ml + 1 ng/ml + 0,1 ng/ml no peptide
SFU/50000 cells
GL9-line + GILGFVFTL GL9-line + SLYNTVATL SL9-line + SLYNTVATL SL9-line + GILGFVFTL
E F
50 100 150 200 250 300 350 400 + 20 µg/ml + 10 µg/ml + 1 µg/ml + 100 ng/ml + 10 ng/ml + 1 ng/ml + 0,1 ng/ml no peptide
Cross-reactive TCR show equally efficient recognition of SL9 and GL9 peptides in peptide titration experiments in g-IFN-ELISPOT assays
26 SL9/ GL9-cross-reactive CTL lines (10 SL9- and 16 GL9-stimulated CTL lines)
SLIDE 12
CD4 counts and viral loads in patients without ART
No significant differences regarding recognition of SL9/GL9
CR: cross-recognition
SLIDE 13 * higher CD4 counts in patients with recognition of SL9. p = 0.007 ## lower viral loads in patients with reognition of SL9. p=0.026 Kein Unterschied bei Patienten mit und ohne Kreuzreaktion: CR+ vs CR-
CD4 counts and viral loads in patients on ART
SLIDE 14
Conclusions
HLA-A2+ HIV-1-infected patients, but not HIV-1-negative subjects, frequently generate SL9/GL9-cross-reactive CTL
This indicates, that cross-reactive CTL are primed by HIV-1 and not by influenza
SL9-specific CTL are associated with higher CD4 counts and lower viral loads in patients on ART
SL9/GL9-cross-reactive CTL do not influence the course of HIV-1-infection
Further studies are needed to evaluate whether HLA-A2+ HIV-1-infected subjects with SL9/GL9-CTL have a lower risk for influenza infection or disease.
SLIDE 15
Angela Hückelhoven Jennifer Etschel Sandra Müller-Schmucker Kathrin Zitzelsberger Silke Bergmann Ellen Harrer
Hückelhoven et al., JAIDS 2015
SLIDE 16 Cross-reaction SL9-specific CTL GL9-specific CTL SL9+,GL9+ SL9+, GL9- GL9+, SL9+ GL9+,SL9- + SLYNTVATL 66 6 69 + GILGF-F-- 66 69 2 + --F------ 12 4 6 1 + --F-A---- 2 6 1 + --Y-A---- 2 4 2 + -------Y- 7 9 + ----A--V- 3 1 2 + ----A--A- 3 7 + -------V- 11 5 7 + --F--I--- 7 2 8 + --F----V- 10 5 5 + ------SA- 4 1 5 + ----A--S- 2 3
Cross-recognition of 11 different SL9 variants by SL9- and GL9-specific CTL lines.
SLIDE 17 25 50 75 100 125 150 175 200 225 250 275
GL9 CTL recognizing SL9 SL9 CTL recognizing GL9 Magnitude of response in %
Cross-recognition to SL9 or GL9 in % of recognition
- f the peptide used for stimulation
