I am an interdisciplinary research fellow, funded by CRUK, working in the groups of Jon Essex, Mark Cragg and Ivo Tews. I am interested in integrating structural biology and computational modelling methods to understand biological activity.

Antibody dynamics

Antibody activity has long been thought to be largely dictated by epitope and affinity. However, antibody dynamics can also play a crucial role. It had been identified that when targetting the tumour necrosis factor receptor (TNFR) CD40, the human IgG2 isotype was more active than the human IgG1 isotype. The key difference between these two isotypes is the antibody hinge region.

During my PhD, I investigated the role of the antibody hinge region in controlling antibody dynamics. I used a combination of x-ray crystallography with anomalous scattering, small-angle x-ray scattering (SAXS) and molecular dynamics (MD) simulations to identify that antibodies with increased rigidity gave higher levels of agonism when targetting CD40. I also employed enhanced sampling methods to gain a deeper understanding of the key structural drivers of conformational restriction.¹

I am now developing this knowledge to further tune antibody agonism and apply the findings to a broader range of key immune receptors.

Antibody-antigen interactions

Investigating the interaction of antibodies with their antigens at the atomic level is key to understanding and modifying their activities. Using an integrative structural biology and modelling approach, I have worked on understanding the modes of action of several antibodies targetting a range of immune receptors.

CD32b
CD32b is a critical immunoregulatory receptor, targeted in the treatment of both cancer and autoimmunity.² As part of my PhD, I worked on understanding the structural basis for agonism/antagonism for antibodies targetting this key receptor, identifying that a combination of both epitope and affinity were key defining levels of agonism.

CD40
To understand the role of the epitope in antibodies targetting CD40, I used a combination of data-driven antibody-antigen docking and SAXS to determine models of CD40-Fab complexes.³ Developing on these findings, I am now looking at computational methods to understand and predict how differences in affinity can modulate activity.

LILRB3
LILRB3 is an inhibitory member of the leukocyte immunoglobulin-like receptor (LILR) family and represents a potential target for cancer immunotherapy.⁴ In collaboration with the group of Ali Roghanian, I am seeking to elucidate how antibody epitope links to biological activity for this system using a combination of x-ray crystallography, SAXS and cryo-EM.

Nectin-4
Nectin-4 is a cell surface receptor over-expressed in multiple human malignancies. In collaboration with the group of Sally Ward, I am working to understand the structural modes by which antibodies target nectin 4 in order to develop pH-dependent antibodies.

CD27
CD27 is a member of the TNFR superfamily acting as a co-stimulatory immune checkpoint molecule. In collaboration with the Lim group, I worked to define the binding epitope of a panel of six antibodies targetting CD27, using a data-driven docking approach.⁵

Cell surface modelling

It is known that for agonism to occur for anti-CD40 antibodies, clustering of the receptor is key.⁶ I am now looking at methods to model these cell surface interactions to attempt to understand the key drivers of agonism, whether that be antibody binding epitope, affinity, dynamics or combinations of the three.

Other collaborations

I am currently collaborating with the groups of Salah Mansour and Salim Khakoo. With the Mansour group, we are working to engineer 𝛾δ TCR receptors to ensure heterodimer formation during protein refolding. With the Khakoo group, I have worked on understanding the structural basis for differences in affinities in KIR2DS2-peptide-HLA-C complexes.

Supervision

I currently help with the supervision of several PhD students.

Izzy Elliott works on applying and developing the lessons learnt about antibody hinge dynamics during my PhD to a broader set of therapeutically interesting targets in the TNFR superfamily.

Cameron Brown is working with the SAXS beamline B21 at Diamond Light Source to develop a combined SAXS-MD pipeline. This will greatly improve the amount of information that can be routinely derived from a SAXS experiment.

Anthony Messer is working on developing and improving antibodies targeting Y. pestis, the causative agent of the plague. Anthony will be using a combination of structural biology techniques, including X-ray crystallography and SAXS, along with computational modelling during his project.

Teaching

I am involved in the teaching of molecular visualisation programmes including PyMOL and Chimera to MSci and MRes students.

References

1. Orr, C.M., Fisher, H. et al. (2022). Hinge disulfides in human IgG2 CD40 antibodies modulate receptor signaling by regulation of conformation and flexibility. Science Immunology, 7(73). doi:10.1126/sciimmunol.abm3723
2. Roghanian, A. et al. (2018). New revelations from an old receptor: Immunoregulatory functions of the inhibitory Fc gamma receptor, FcγRIIB (CD32B). Journal of Leukocyte Biology, 103(6), pp.1077–1088. doi:10.1002/jlb.2mir0917-354r
3. Yu, X., Chan, H.T.C., Fisher, H. et al. (2020). Isotype Switching Converts Anti-CD40 Antagonism to Agonism to Elicit Potent Antitumor Activity. Cancer Cell, 37(6), doi:10.1016/j.ccell.2020.04.013
4. Yeboah, M. et al. (2020). LILRB3 (ILT5) is a myeloid cell checkpoint that elicits profound immunomodulation. JCI Insight, 5(18). doi:10.1172/jci.insight.141593
5. Heckel, F., Turaj, A.H., Fisher, H. et al. Agonistic CD27 antibody potency is determined by epitope-dependent receptor clustering augmented through Fc-engineering. Commun Biol, 5, 229 (2022). doi:10.1038/s42003-022-03182-6
6. Yu, X., James, S., Felce, J.H. et al. TNF receptor agonists induce distinct receptor clusters to mediate differential agonistic activity. Commun Biol, 4, 772 (2021)