The role of HLA-C-specific alloantibodies in enhancing NK cell-mediated responses against tumour cells

Kaur, Amandeep Johal (2021). The role of HLA-C-specific alloantibodies in enhancing NK cell-mediated responses against tumour cells. University of Birmingham. Ph.D.

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Abstract

Engagement between the highly polymorphic human leukocyte antigen-C (HLA-C) and the inhibitory killer immunoglobulin-like receptors (KIRs) proteins acts to supress Natural killer (NK) cell function, which may facilitate tumour cell evasion and promote disease progression. It was hypothesised that overexpression of HLA-C in cancer, and its interaction with KIRs might be disrupted by human HLA-C-specific alloantibodies to enhance NK cell function against tumour cells. Firstly, alloantibodies against HLA-C alleles from the sera of allo-sensitised individuals were confirmed by luminex microbead assay and flow cytometry staining of single HLA-C allele transfected cell lines. Secondly, affinity- purified alloantibodies from sera were applied in an in vitro cell model and NK cell cytotoxicity against HLA-C-specific antibody-coated transfected cells, solid tumour cell lines and primary B-CLL cells was significantly improved. Antibody-dependent cellular cytotoxicity (ADCC) mechanism played a role in enhancing target cell lysis in the presence of purified HLA-C-specific antibodies, which was inhibited by anti-CD16 treatment of NK cells. An ADCC-independent NK cell activation mechanism was also involved as the cytotoxic effect was retained after anti-CD16 treatment of NK cells and in the absence of Fc fragment. Such observations indicate that HLA-C:KIR blockade with HLA-C-specific antibodies can promote NK cell activation. Lastly, attempts to generate recombinant antibodies were hampered by low frequencies of memory B cells within allo-sensitised patients. Immortalisation of B cells by EBV, however, led to the detection of HLA Class I- specific antibodies, confirming the presence of circulating HLA-specific memory B cells. Monoclonal antibodies were generated from CD27+CD38+ plasmablasts from transplant patients with active graft rejection to investigate the alloreactive antibody repertoire during an active immune response, but their specificity was not determined. This study implicates the role of HLA-C in tumour immune resistance and for the first time, demonstrates the potential of HLA-C:KIR blockade with HLA-C-specific alloantibodies to enhance NK cell function.

Type of Work:	Thesis (Doctorates > Ph.D.)
Award Type:	Doctorates > Ph.D.
Supervisor(s):	Supervisor(s) Email ORCID Moss, Paul A. UNSPECIFIED UNSPECIFIED Zuo, Jianmin UNSPECIFIED UNSPECIFIED Briggs, David UNSPECIFIED UNSPECIFIED
Licence:	All rights reserved
College/Faculty:	Colleges (2008 onwards) > College of Medical & Dental Sciences
School or Department:	Institute of Immunology and Immunotherapy
Funders:	Other
Other Funders:	College of Medical and Dental Sciences, University of Birmingham
Subjects:	R Medicine > R Medicine (General) R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology (including Cancer)
URI:	http://etheses.bham.ac.uk/id/eprint/11457

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• The role of HLA-C-specific alloantibodies in enhancing NK cell-mediated responses against tumour cells. (deposited 01 Sep 2022 11:11) [Currently Displayed]

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