HAL Id: inserm-02158889
https://www.hal.inserm.fr/inserm-02158889
Submitted on 18 Jun 2019
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Deciphering anti-HCMV HLA-E-restricted
unconventional CD8 T-cell responses in seropositive HCMV+ hosts
Nicolas Jouand, Céline Bressollette-Bodin, Nathalie Gérard, Magali Giral, Pierrick Guerif, Audrey Rodallec, Romain Oger, Tiphaine Parrot, Anne
Cesbron-Gautier, Nadine Gervois, et al.
To cite this version:
Nicolas Jouand, Céline Bressollette-Bodin, Nathalie Gérard, Magali Giral, Pierrick Guerif, et al.. Deci-phering anti-HCMV HLA-E-restricted unconventional CD8 T-cell responses in seropositive HCMV+ hosts. Cinquième congrès européen d’Immunologie, Sep 2018, Amsterdam, Netherlands. �inserm-02158889�
Summary
Contact: Beatrice.Charreau@univ-nantes.fr
Centre de Recherche en Transplantation et Immunologie, INSERM UMR1064, Nantes, Fr.
Deciphering anti-HCMV HLA-E-restricted unconventional CD8 T-cell responses
in seropositive HCMV+ hosts
Nicolas Jouand, Céline Bressollette-Bodin, Nathalie Gérard, Magali Giral, Pierrick Guérif
,Audrey Rodallec, Romain Oger, Tiphaine Parrot,
Anne Cesbron-Gautier,Nadine Gervois
*and Béatrice Charreau
*Conclusion
HCMV infection frequently leads to the long-term persistence of a large subset of
unconventional, HLA-E-restricted, CD8 T lymphocytes directed against a strain-specific viral
peptide but that display potential autologous and allogeneic recognition.
Human cytomegalovirus (HCMV) causes severe illness and poor outcome in immunocompromised hosts such as transplant recipients and HIV-infected patients. Cytotoxic CD8 T cells against HCMV antigens (pp65, IE1) presented by classical HLA class-I molecules are major cellular components of the protective anti-HCMV immunity. HLA-E-restricted CD8 T cells targeting HCMV UL40 leader peptides (Lp) have been recently reported as unconventional T-cell responses also observed in some hosts but they still need clinical and functional characterization. Our study aimed to provide a qualitative and quantitative ex vivo analysis of HLA-EUL40 CD8 T-cell responses, in a large cohort (n=144) of kidney transplant recipients and healthy volunteers, and to elucidate determining factors. HLA-EUL40 CD8 T-cells were detected in >30% of seropositive HCMV+ hosts and
may represent >30% of total circulating CD8 αβT cells at a time point. We identified host-related genetic factors (HLA-A*02 and HLA-E genotype) and HCMV strain, determining the sequence of UL40Lp, as critical parameters for this response. HLA-EUL40 CD8 are effector memory T cells that appear early post-infection as monoclonal/oligoclonal populations and persist for life. Although specifically induced in response to HCMV infection, a key feature of these cells is their potential ability to be also responsive against self and allogeneic HLA resulting from sequence homology between HLA-ILp and UL40Lp. Thus we established that unconventional HLA-EUL40 CD8 T cells belong to the common immune arsenal against HCMV. Their functions remain to be defined toward infection as well as their potential side effect in contexts such as autoimmunity and transplantation. UL4015-23 peptide from infecting HCMV strain KTR Detection of HLA-EUL40 specific CD8 T cells #108 VMAPRTLIL HLA-E/ VMAPRTLIL CD8 α 2.9% VMAPRTLLL #109 HLA-E/ VMAPRTLLL CD8 α 9.5% VMAPRSLLL #105 CD8 α HLA-E/ VMAPRSLLL 32.4% CD8 α VMAPRTLLL #026 HLA-E/ VMAPRTLLL 38.6% 0 1 0 2 0 3 0 4 0 0 1 2 3 4 5 6 A m in o aci d va ri an ts (n)
Amino acid position (1-37)
UL4015-23 P1 P9 A 1.0 0.5 0.0 P robabi lity 1 2 3 4 5 6 7 8 9
Amino acid position (1-9)
B C 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 0 5 1 0 1 5 2 0 0 2 4 6 8 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 0 5 1 0 2 0 3 0 4 0 5 0 0 2 4 6 8 0 1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 0 1 2 5 1 0 1 5 2 0 0 2 4 6 8 LT CD8 HLA-EUL40 LT CD8 HLA-A*02pp65 HCMV blood viremia
% of tetramers + among CD8 TCRαβ T cells
0 2 4 6 8 1 0 N L V P M V A T V V M A P Q S L L L V M T P R T L V L V M A P R S L IL V M A P R S L L L V M A P R T V L L V M A P R T L V L V M A P R T L L L V M A P R T L IL 2 0 3 0 4 0 5 0 HLA-E HLA-A*02 n 23 22 17 18 20 15 7 2 32 HLA-EUL40 CD8 T-cell responders (n=31) Both Transplant Self Others None #0 56 #0 52 #0 19 #1 06 #0 60 #0 12 #1 03 #0 86 #0 15 #0 18 #0 77 #1 04 #0 28 #0 02 #0 67 #0 39 #0 68 #0 08 #0 26 #1 09 #1 08 #1 07 #1 05 #0 22 #0 12 #0 24 #0 13 #0 08 #0 20 #0 17 #0 21 V M A P R T L IL V M A P R T L L L V M A P R T L V L V M A P R T V L L K T R H V * * * * * * * * * * * * % of tetr amer s + amon g C D 8 TC R αβ T cel ls UL4015-23 only UL4015-23 Or HLA-I3-11 #0 56 #0 52 #0 19 #1 06 #0 60 #0 12 #1 03 #0 86 #0 15 #0 18 #0 77 #1 04 #0 28 #0 02 #0 67 #0 39 #0 68 #0 08 #0 26 #1 09 #1 08 #1 07 #1 05 #0 22 #0 12 #0 24 #0 13 #0 08 #0 20 #0 17 #0 21 V M A P R T L IL V M A P R T L L L V M A P R T L V L V M A P R T V L L V M A P R S L L L V M A P R S L IL V M T P R T L V L V M A P Q S L L L K T R H V 0 5 1 0 1 5 2 0 2 5 3 0 3 5
UL40-specific HLA-E-restricted CD8 T cells were analysed ex vivo in blood samples after PBMC isolation using a multi-parameter (CD3+CD8α+TCRγδ-) flow cytometry assay subsequent to the blockade of the CD94 receptor. Our protocol allows a sensitive (threshold of detection: 0.1% of total CD8 TCRαβ T cells) and peptide-specific analysis of HLA-EUL40 CD8 T-cell populations. Banked blood samples, harvested at M12 post-transplantation, were investigated using a set of HLA-E tetramers loaded with 8 different UL4015-23 peptides to encompass the usual UL4015-23 variability among common HCMV strains. The 8 HLA-E tetramer/peptide complexes were tested individually.
Detection of UL40-specific HLA-E-restricted CD8 T cells. Our results reveal a very high incidence (>30%)
of HLA-EUL40CD8 T-cell responses in HCMV+hosts with
no significant difference between transplanted patients and healthy individuals suggesting that antiviral and immunosuppressive regimens have no impact of these cell subsets at M12. These cells are detected more
frequently in hosts carrying an HLA-A*02 allele.
Unconventional CD8 T cells can be detected
independently of detectable conventional HLA-A*02pp65
T-cell response. Presence of HLA-EUL40 CD8 T cells early
post-infection (primary or reactivation) as well as at latency suggests long lived cell subsets consistent with memory anti-HCMV response.
HLA-E/VMAPRTLIL HLA-A*02/NLVPMVATV HLA-E-restricted T cells HLA-A*02-restricted T cells 10% 1% 0.1% 0% CD8 α CD8 α
① Detection of HLA-E
UL40CD8 T cells in blood samples
② A set of 11 HLA-E tetramers loaded with UL40 SP
1.
Starting point: A specific & sensitive assay
2.
Detection of anti-HCMV HLA-E-restricted CD8 T cells in HCMV seropositive kidney transplant recipients
→ Parallel analysis of conventional (HLA-A*02pp65)
and HLA-EUL40 anti-HCMV CD8 T cells
Samples collected at M12 post-transplantation
HCMV+ and HCMV- Kidney transplant recipients (n=121)
HCMV+ Healthy volunteers (HV,n=25)
A retrospective cohort study
3.
Characteristics of anti-HCMV HLA-E-restricted CD8 T cells in hosts
EUL40 CD8 T-cell responses were investigated using HLA-E tetramers loaded with the UL40 peptide that we identified in their own infecting strain, HCMV strain-specific HLA-E-restricted
T cells were detected in patients. Importantly, percentages of
HLA-EUL40 CD8 T cells vary from 2.9% up to 38.6% of total
CD8 αβT cells in the blood sample at the time of detection.
% of te tra me rs + am on g tot al CD8 + TCR αβ T ce lls HC MV blood v ire mia (lo g10 copy per 1 0 6 ce ll s) Time post-transplantation (months)
HLA-EUL40 CD8 T-cell population expressing a dominant Vβ chain sub-family was obtained for 3 patients while another one gives rise to oligoclonal populations (from 2 to 6 subsets detected) with variable distribution. This suggests the sorting of multiple, coexisting,
HLA-EUL40 CD8 T-cell populations in this patient. Interestingly, a broad TCR-Vβ repertoire was
found with 16 Vβ identified (Vβ1, 2, 3, 5.1, 7.1, 8, 9, 12, 13.1, 13.2, 13.6, 14, 16, 17, 22 and
23) thus enlarging the Vβ repertoire previously described for these cells.
HLA-EUL40 CD8 T cells target viral UL4015-23sequence
in a strain-specific manner
Time course and magnitude of
HLA-EUL40 and HLA-A*02pp65 CD8 T-cell
responses are parallel
UL4015-23-specific HLA-E-restricted CD8 T cells are effector memory T cells with broad TCR Vβ repertoire and peptide recognition
HLA-EUL40 CD8 T-cell responses display potential recognition of self and allogeneic HLA peptides
P.C3.04.05
The authors disclose no conflict of interest.
