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HLA class I- and class II-restricted T cell receptors for immunotherapy of human cytomegalovirus disease
HLA class I- and class II-restricted T cell receptors for immunotherapy of human cytomegalovirus disease
Human cytomegalovirus (HCMV) frequently reactivates after hematopoietic stem cell transplantation (HSCT). Antiviral medication is not universally effective and has side effects that prohibit prophylaxis and limit pre-emptive use. Adoptive transfer of HCMV-specific T lymphocytes can protect patients at risk of HCMV disease, but such T cells are difficult to obtain if the HSC donor is HCMV-negative. Transferring the T cell receptor (TCR) genes of HCMV-specific T cell clones to donor T cells will convey HCMV specificity to those cells. But if αβ T cells are engineered to co-express a second αβ TCR, mixed αβ TCR heterodimers of unknown and potentially hazardous specificity may form. This problem can be solved by expressing αβ TCRs in γδ T cells from the donor. HCMV-specific CD8+ T cells limit HCMV infection, but presentation of their antigenic peptides is effectively impaired by HCMV’s immunoevasins, especially in case of human leukocyte antigen (HLA)-A and -B allotypes. In contrast, CD8+ T cells restricted by HLA-C*07:02 resist the immunoevasins. In this study, the genes of eight HLA-C*07:02-restricted TCRs specific for immediate-early protein 1 (IE-1) or UL28 protein were derived from CD8+ T cell clones and retrovirally transferred into T cells from HCMV-negative donors. While all of those TCRs mediated strong recognition of an HCMV strain that is devoid of the four immunoevasins, their response to target cells infected with wild-type HCMV strains was weaker. Transduction experiments with different variations of the TCRs pointed to the existence of additional T cell-endogenous factors that contribute to recognition of infected cells. HCMV-specific CD4+ T cells are known to play a critical role in controlling HCMV and maintaining immunity. Nonetheless, possibilities of their transgenic generation have not been explored. In this study, HCMV-specific TCRs from CD4+ T cell clones were expressed in T cells from HCMV-negative donors. A panel of ten HCMV-specific, HLA class II-restricted TCRs was established that target seven distinct epitopes of phosphoprotein 65 (pp65) and IE-1 presented by a wide range of HLA class II allotypes. These TCR genes were retrovirally transferred into αβ T cells and γδ T cells from HCMV-negative donors. The resulting T cells specifically recognised HLA-matched, HCMV-infected dendritic cells. TCR-transduced αβ and γδ T cells were similarly effective, but backgrounds due to alloreactivity were even lower in γδ T cells than in αβ T cells. Experiments with inactivated virus showed that pp65-specific, HLA class II-restricted TCRs conveyed similar sensitivity towards HCMV-infected target cells and target cells that had acquired viral proteins through ingestion of extracellular material. In contrast, IE-1-specific, HLA class II-restricted TCRs mediated selective recognition of bona fide infected target cells. These results identify γδ T cells that transgenically express HLA class II-restricted TCRs as particularly promising immunotherapeutic agents against HCMV infection.
cytomegalovirus (CMV), adoptive T cell therapy, TCR-transgenic T cells, gammadelta T cells, HLA class II
Joos, Clemens
2019
English
Universitätsbibliothek der Ludwig-Maximilians-Universität München
Joos, Clemens (2019): HLA class I- and class II-restricted T cell receptors for immunotherapy of human cytomegalovirus disease. Dissertation, LMU München: Faculty of Chemistry and Pharmacy
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Abstract

Human cytomegalovirus (HCMV) frequently reactivates after hematopoietic stem cell transplantation (HSCT). Antiviral medication is not universally effective and has side effects that prohibit prophylaxis and limit pre-emptive use. Adoptive transfer of HCMV-specific T lymphocytes can protect patients at risk of HCMV disease, but such T cells are difficult to obtain if the HSC donor is HCMV-negative. Transferring the T cell receptor (TCR) genes of HCMV-specific T cell clones to donor T cells will convey HCMV specificity to those cells. But if αβ T cells are engineered to co-express a second αβ TCR, mixed αβ TCR heterodimers of unknown and potentially hazardous specificity may form. This problem can be solved by expressing αβ TCRs in γδ T cells from the donor. HCMV-specific CD8+ T cells limit HCMV infection, but presentation of their antigenic peptides is effectively impaired by HCMV’s immunoevasins, especially in case of human leukocyte antigen (HLA)-A and -B allotypes. In contrast, CD8+ T cells restricted by HLA-C*07:02 resist the immunoevasins. In this study, the genes of eight HLA-C*07:02-restricted TCRs specific for immediate-early protein 1 (IE-1) or UL28 protein were derived from CD8+ T cell clones and retrovirally transferred into T cells from HCMV-negative donors. While all of those TCRs mediated strong recognition of an HCMV strain that is devoid of the four immunoevasins, their response to target cells infected with wild-type HCMV strains was weaker. Transduction experiments with different variations of the TCRs pointed to the existence of additional T cell-endogenous factors that contribute to recognition of infected cells. HCMV-specific CD4+ T cells are known to play a critical role in controlling HCMV and maintaining immunity. Nonetheless, possibilities of their transgenic generation have not been explored. In this study, HCMV-specific TCRs from CD4+ T cell clones were expressed in T cells from HCMV-negative donors. A panel of ten HCMV-specific, HLA class II-restricted TCRs was established that target seven distinct epitopes of phosphoprotein 65 (pp65) and IE-1 presented by a wide range of HLA class II allotypes. These TCR genes were retrovirally transferred into αβ T cells and γδ T cells from HCMV-negative donors. The resulting T cells specifically recognised HLA-matched, HCMV-infected dendritic cells. TCR-transduced αβ and γδ T cells were similarly effective, but backgrounds due to alloreactivity were even lower in γδ T cells than in αβ T cells. Experiments with inactivated virus showed that pp65-specific, HLA class II-restricted TCRs conveyed similar sensitivity towards HCMV-infected target cells and target cells that had acquired viral proteins through ingestion of extracellular material. In contrast, IE-1-specific, HLA class II-restricted TCRs mediated selective recognition of bona fide infected target cells. These results identify γδ T cells that transgenically express HLA class II-restricted TCRs as particularly promising immunotherapeutic agents against HCMV infection.