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Department of Veterinary Medicine

Cambridge Veterinary School

Studying at Cambridge


Dr Rachel Hewitt

Dr Rachel Hewitt

Postdoctoral Researcher


Life Member of Clare Hall, Cambridge.

Subject groups/Research projects

Infection and Immunity:

Research Interests

The primary focus of my work is investigating how nano and sub-micron sized particles influence cellular immune responses, with a particular interest in how particle-immune cell interactions may ultimately influence adaptive immunity. This work feeds into the over-arching aims of the Biomineral Research Group led by Jonathan Powell.

Conventional and imaging flow cytometry are key techniques employed in my area of study, and I am especially passionate about the utilization of imaging flow cytometry for fully quantitative deep profiling of cells and internal cellular processes, to advance our understanding of cellular mechanisms in heath and disease, for the development of novel therapeutics and improved diagnostics.


  • T cells
  • Image flow cytometry
  • Immunity
  • Nanoscience

Collaborators outside this directory

Key Publications

Vis B, Hewitt RE, Faria N, Bastos C, Chappell H, Pele L, Jugdaohsingh R, Kinrade SD, Powell JJ. Non-Functionalized Ultrasmall Silica Nanoparticles Directly and Size-Selectively Activate T Cells. ACS Nano. 2018 Nov 27;12(11):10843-10854.

Rachel E Hewitt, Bradley Vis, Laetitia C. Pele, Nuno Faria and Jonathan J. Powell. Imaging flow cytometry assays for quantifying pigment grade titanium dioxide particle internalization and interactions with immune cells in whole blood. Cytometry Part A 91 (10), 1009-1020.

Rachel E Hewitt, Jack Robertson, Carolin Haas, Laetitia C Pele, Jonathan Powell. Reduction of T-helper Cell Responses to Recall Antigen Mediated by Co-delivery with Peptidoglycan via the Intestinal Nanomineral-Antigen Pathway. Front Immunol. 2017 Mar 17;8:284.

Laetitia C Pele, Emma Thomas-McKay, Carolin T Haas, Rachel E Hewitt, Jack Robertson, Jeremy Skepper, Andy Brown, Juan Carlos Hernandez-Garrido, Paul A Midgley, Nuno Faria & Jonathan J Powell. Synthetic mimetics of the endogenous gastrointestinal nanomineral: silent constructs that trap macromolecules for intracellular delivery. Nanomedicine. 2016 Jul 29;13(2):619-630.

Jack Robertson, Carolin T Haas, Laetitia C Pele, Tom P Monie, Charles Charalambos, Miles Parkes, Rachel E Hewitt and Jonathan J Powell. Intestinal APCs of the endogenous nanomineral pathway fail to express PD-L1 in Crohn’s disease. Sci Rep. 2016 May 26;6:26747.

Powell JJ, Thomas-McKay E, Thoree V, Robertson J, Hewitt RE, Skepper JN, Brown A, Hernandez-Garrido JC, Midgley PA, Gomez-Morilla I, Grime GW, Kirkby KJ, Mabbott NA, Donaldson DS, Williams IR, Rios D, Girardin SE, Haas CT, Bruggraber SF, Laman JD, Tanriver Y, Lombardi G, Lechler R, Thompson RP, Pele LC. An endogenous nanomineral chaperones luminal antigen and peptidoglycan to intestinal immune cells. Nat Nanotechnol. 2015 Mar 9.

Hewitt RE, Pele LC, Charalambos C, Tremelling M, Parkes M, PowellJJ. Immuno-inhibitory PD-L1 can be induced by a Peptidoglycan/NOD2 mediated pathway in primary monocytic cells and is deficient in Crohn’s patients with homozygous NOD2 mutations. Clin Immunol. 2012 May;143(2):162-9.

A full publications list can be found here