Article Text

Download PDFPDF

655 Landscape of helper and regulatory CD4+ T cells in melanoma
  1. Giacomo Oliveira1,
  2. Kari Stromhaug1,
  3. Susan Klaeger2,
  4. Nicoletta Cieri1,
  5. Bryan Iorgulescu1,
  6. Shuqiang Li1,
  7. David Braun1,
  8. Donna Neuberg1,
  9. Steven Carr2,
  10. Kenneth Livak1,
  11. Dennie Tompers3,
  12. Edward Fritsch1,
  13. Megan Wind-Rotolo4,
  14. Nir Hacohen2,
  15. Moshe Sade-Feldman3,
  16. Derin Keskin1,
  17. Patrick Ott1,
  18. Scott Rodig5,
  19. Genevive Boland3 and
  20. Catherine Wu1
  1. 1Dana-Farber Cancer Institute, Boston, United States
  2. 2Broad Institute of MIT and Harvard, Cambridge, United States
  3. 3Massachusetts General Hospital, Boston, United States
  4. 4Bristol-Myers Squibb, Princeton, NJ, United States
  5. 5Brigham and Women’s Hospital, Boston, MA, United States


Background Within the tumor microenvironment, distinct CD4+ T cell subsets can play different and even opposite roles either promoting or suppressing anti-tumor responses through the recognition of antigens presented by human leukocyte antigen (HLA) class II molecules. However, how cancers co-opt these processes to shape the intratumoral CD4+ landscape and achieve immune evasion remains incompletely understood.

Methods We performed single-cell characterization of CD4+ tumor infiltrating lymphocytes (TILs) collected from four human melanoma with low or high HLA-class II expression and we utilized TCR reconstruction and antigen specificity screening to unambiguously discover the tumor reactivity of CD4+ TILs. By testing TCR-transduced T cells against autologous patient-derived melanoma cell lines or against autologous antigen presenting cells (APCs) loaded with tumor lysates, we assessed the capacity of CD4+ TCRs to directly or indirectly recognize tumor cells. We defined the antigen-specificity of antitumor CD4+ TCRs by assessing their reactivity towards personal neoantigens (NeoAg) or public melanoma associated antigens (MAAs). Finally, we correlated NeoAg burden and HLA-class II expression in a series of 116 melanoma specimens from 4 independent cohorts of patients.

Results Analysis of single-cell data showed that the cluster distribution of cells within each CD4+ TCR clonotype family was highly homogeneous and appeared to follow 3 distinct major phenotypes, corresponding to non-exhausted memory cells, exhausted cells and regulatory cells (TRegs). Strikingly, clonally expanded CD4+ TReg-TILs were highly abundant within the tumor microenvironment of HLA class IIpos melanomas. We found that TCRs from exhausted cytotoxic CD4+ T cells could be directly triggered by melanoma cells not only through recognition of HLA class II restricted antigens, but also through presentation of HLA class I restricted MAAs. TReg-TCRs could be indirectly elicited through presentation of tumor antigens via APCs. Notably, numerous tumor-reactive CD4+ TReg-TCRs were directly stimulated by HLA class IIpos melanoma and demonstrated specificity for melanoma NeoAgs. In HLA class IIpos melanomas, the clonal expansion of numerous tumor-reactive and NeoAg-specific TRegs-clones appeared to be favored by a dramatically high tumor NeoAg load. Analysis of 116 melanoma specimens confirmed the association of elevated HLA-class II expression with extremely high NeoAg burden.

Conclusions Our data elucidate the landscape of infiltrating CD4+ T cells in melanoma and point to presentation of HLA-class II restricted NeoAgs and direct engagement of immunosuppressive CD4+ TRegs as a novel mechanism of immune evasion favored in HLA class IIpos melanoma.

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.