Sarah Johnson was born in Nottingham in the UK and received her Bachelor of Science in Cell Physiology and Pharmacology from the University of Leicester in 2013 and Master of Science in Bioengineering from Imperial College London in 2015. She is currently a final year student in the Moore Lab.
Sarah’s primary research project focuses on how lymph node swelling during the immune response affects immune cell trafficking through the lymph node. The cell mediated response is initiated when antigen-presenting dendritic cells drain to lymph nodes in afferent lymphatics and interact with T cells that enter from a blood vessels network inside the lymph node. When T cells and Dendritic cells interact, a small fraction of T cells will ‘recognise’ the antigen fragments presented through complementary T cell receptor expression. If the antigenic signal is strong enough, T cells will become activated and undergo several rounds of proliferation and differentiate into effector cells that leave the lymph node in efferent lymph. T cell trafficking is carefully coordinated during homeostasis through the distribution of signalling molecules in specific compartments of the lymph node, the lymph node structure and T receptor regulation. During the cell mediated response T cell recruitment is increased, the network of blood vessels expands and the LN swells to several times it’s volume. The effect of this major macroscale change on the T cell interactions and transit is unknown. It is also known that expression of the T cell surface receptor Sphingosine-1-Phosphate 1 (S1P1r) is required for T cell egress from the LN into afferent lymphatics and expression is modulated when T cells respond to antigenic stimuli. Agent based modelling is used to model realistic numbers of T cells responding to signal presented by dendritic cells inside the central compartment of a LN, including this S1P1r modulation, lymph node swelling and recruitment change. This technique applies simple probabilistic rules to each individual agent. The resulting individual behaviours that can be influenced by each cell’s environment can uncover emergent or flock behaviour.
Sarah is also involved in a collaborative project between Prof. Fotopoulou group based at Hammersmith Hospital (Imperial College Healthcare), the Moore lab and Dr Chakraborty at Texas A&M ,investigating miRNA expression in lymphatic vessels from epithelial ovarian cancer patients. Unlike many studies, these vessels are not peri-tumoural but functional lymphatic vessels obtained during lymph node staging. A combination of miRNA extraction and Immunohistochemical studies are used to identify correlation between inflammatory state and/or the presence of cancer cells in the lymphatic vessel to the miRNA expression.
Sarah is a cross country and track runner, previously competed at a national level having gained a U20 England Athletics silver in the 5000m in 2011. As an Imperial Sports Scholar, Sarah has represented the university at a national level on multiple occasions throughout her PhD, gaining a silver medal in the 2015 British Universities Championships in the 10000m outdoor athletics event and silver in the 2014 marathon event within London marathon. She now regularly competes for Thames Valley Harriers. Sarah also enjoys music having previously been a member of Staffordshire symphony orchestra.