Engineering novel antibody-based NK cell-directed immunotherapies for the control of human cytomegalovirus

Preston, Hannah 2026. Engineering novel antibody-based NK cell-directed immunotherapies for the control of human cytomegalovirus. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Human cytomegalovirus (HCMV) causes substantial morbidity and mortality in immunocompromised individuals and after congenital infection. Despite many trials, no vaccines are licensed. Most vaccine strategies have focussed on the induction of neutralising antibodies that block infection by cell-free virus, however, HCMV predominantly spreads via cell-to-cell transmission, reducing the effectiveness of this approach. Consequently, immunotherapies that directly target infected cells are required. This thesis therefore investigated the capacity of monoclonal antibodies (mAbs) to bind HCMV-infected cells and trigger natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC). Proteomic and immunological profiling identified mAbs targeting the non-entry glycoprotein UL141 could efficiently control virus through ADCC when used as a mix of 5. However, a mix of mAbs is difficult to translate into clinical use. Comparisons of antibody-dependent NK cell activity (ADNKA) against HCMV and tumour antigens revealed that restricted cell-surface trafficking, and viral-induced changes to the infected cell, combine to limit ADNKA efficacy. The former could be overcome through mAbs targeting UL141 and the latter through combining mAbs. To determine whether the requirement for multiple mAbs could be circumvented, a range of antibodylike constructs, including BiKEs, TriKEs, ANKETs and Redirected Optimised Cell Killers (ROCKs) were engineered, incorporating modifications to enhance antibody binding, and subsequent NK activation and proliferation. Following systematic screening, ROCKs showed superior control of HCMV, mediating potent ADNKA as single molecules and significantly enhancing virus control via ADCC at concentrations 100-fold lower than polyclonal IgG from natural infection. ROCKs drove enhanced lytic granule convergence at the NK microtubule-organising centre (MTOC) and polarisation towards ROCKopsonised target cells, along with increased CD16 clustering at the NK immune synapse. Unlike conventional IgG, ROCKs engaged CD16 in a way that bypassed ADAM17-mediated CD16 shedding, enabling sustained NK cytotoxicity. These findings establish a novel monoclonal immunotherapeutic strategy against HCMV and demonstrate how antibody-like molecules can be engineered to maximise NK antiviral activity against highly immune-evasive targets expressing low levels of antigen.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Schools > Medicine
Date of First Compliant Deposit:	23 October 2026
Last Modified:	26 Oct 2026 16:04
URI:	https://orca.cardiff.ac.uk/id/eprint/190395

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