Page 206 - Haematologica Vol. 110 - January 2025

LETTER TO THE EDITOR
pulsed cells with epitope peptides from LMP2A or the dimethyl sulfoxide solvent (control); these peptides bind to HLA class I on the cell surface and are presented to T cells. Two different LMP2A specific CD8+ T-cell clones recognizing distinct LMP2A peptides, HLA-A24-restricted TYG and HLA-A2-restricted CLG, were used as effec- tor cells and interferon-g release was used to measure CD8+ T-cell recognition. As expected, neither T-cell clone recognized the EBV-negative cHL lines infected with control virus or pulsed with dimethyl sulfoxide. Howev- er, both T-cell clones recognized the cHL cells infected with MVA-LMP2A or pulsed with their cognate peptide, producing interferon-g (Figure 3A, B). We found that rec- ognition was significantly decreased in the presence of soluble recombinant GPNMB (rGPNMB). Interestingly, this inhibition was strongest at the lowest dose of rGPNMB and diminished at the highest dose tested (Figure 3A, B). We repeated this experiment using the optimal inhibitory dose of rGPNMB (0.04 μg/mL) and included two further T-cell clones specific for additional LMP2A epitopes, HLA-A2-restricted FLY and HLA-A11-restricted SSC, and an additional EBV-negative HLA-A11-positive cHL line, L540. In each case, recognition of MVA-LMP2A infected cHL cells was decreased in the presence of rGPNMB (On- line Supplementary Figure S3A). Finally, to confirm the effects of rGPNMB on T-cell activation in primary cells, we activated peripheral blood mononuclear cells (PBMC) with a range of different concentrations of soluble CD3/ CD28 activators and measured interferon-g release in the presence/absence of rGPNMB (0.04 μg/mL). As expected, rGPNMB significantly reduced the activation of T cells (Online Supplementary Figure S3B).
In summary, we have shown that TAM in the cHL TME strongly express GPNMB. Levels of surface GPNMB were increased upon in vitro exposure of macrophages to cHL CM or following direct co-culture with cHL cells. These effects were associated with M2 polarization. Optimal release of the soluble isoform, sGPNMB, by macrophages was achieved only following direct co-culture with cHL cells. Importantly, low levels of soluble recombinant rGPNMB inhibited the recognition of cHL cells by CD8+ T cells specific for epitopes from the LMP2A protein, a well-known tumor antigen expressed in around 30-50% of all cases of cHL.1 Our results indicate that blocking GPNMB in the TME of cHL could enhance tumor-specific CD8+ T-cell recognition.
Authors
Navta Masand,1 Tracey A. Perry,1 Matthew Pugh,2 Eanna Fennell,3 Aoife Hennessy,3 Wenbin Wei,1,4 Katerina Bouchalova,5 David Burns,6 Pamela Kearns,1,7 Graham Taylor,2 Katerina Vrzalikova2,8 and Paul G. Murray3,8,9
1Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK; 2Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK; 3Limerick Digital Cancer Research Center, Bernal Institute and Health Research Institute and School of Medicine, University of Limerick, Limerick, Ireland; 4The Palatine Center, Durham University, Durham, UK; 5Department of Pediatrics, Faculty of Medicine and Dentistry, Palacky University and University Hospital Olomouc, Olomouc, Czech Republic; 6University Hospitals Plymouth NHS Trust, Plymouth, UK; 7National Institute for Health Research (NIHR) Birmingham Biomedical Research Center, University of Birmingham, Birmingham, UK; 8Royal College of Surgeons in Ireland Medical University of Bahrain, Manama, Bahrain and 9Department of Clinical and Molecular Pathology, Institute of Molecular and Translational Medicine, Faculty of Medicine and Dentistry, Palacky University and University Hospital Olomouc, Olomouc, Czech Republic
Correspondence:
P. MURRAY - paul.murray@ul.ie, pamurray@rcsi-mub.com
K. VRZALIKOVA - k.vrzalikova@bham.ac.uk, kmurray@rcsi-mub. com
https://doi.org/10.3324/haematol.2024.285319
Received: February 22, 2024. Accepted: August 16, 2024. Early view: August 22, 2024.
©2025 Ferrata Storti Foundation Published under a CC BY-NC license
Disclosures
No conflicts of interest to disclose.
Contributions
NM, TAP, KV, PK, GT and PGM designed the study. NM, TAP and AH performed the experiments. NM, TAP, KV, EF, WW and PGM analyzed the data. MP provided pathology review and interpretation of immunohistochemistry results. KB was involved in sample collection. NM, KV, GT and PGM wrote the manuscript. All authors approved the final version of the manuscript.
Funding
This work was supported by the UK CCLG/Little Princess Trust 701 project grant (CCLGA 2017 18), Blood Cancer UK (No. 13045), European Regional Development Fund Project ENOCH (No. CZ.02.1. 01/0.0/0.0/16_019/0000868) and by the Czech Ministry of Health (DRO: FNOL00098892).
Data-sharing statement
The datasets generated and/or analyzed in this study are available in the Online Supplementary Appendix or from the corresponding author on reasonable request.
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