Ink Trails: Tracking the life and death of memory T cells

Abstract

Every encountered pathogen leaves an imprint on the immune system. This is termed as immune memory. A significant part of this immune memory is stored in a subset of T cells called memory T cells. As memory T cells are experienced in pathogen control, they are of significant interest to immunologists in their search for better vaccine technologies. For example, if the condition and the time of when memory T cells are formed is known, then technologies can be developed that either increase the number of memory T cells produced to better fend off an infection or decrease the number of memory T cells created to limit self-harm in autoimmune diseases. Similarly, if the lifespan of both an individual memory T cell and the memory T-cell population is known, questions on the efficacy and longevity of vaccines can be addressed. Therefore, it is essential to detail the mechanisms underlying the generation and maintenance of memory T cells. This thesis presents experimental data, their mathematical analyses and theoretical simulations that 1) discuss the lifespan of memory T cells, 2) ways to accurately approximate these lifespans, 3) the events leading up to the generation of memory T cells during an immune response and 4) probable mechanisms that could sustain the immunity provided by memory T cells against a pathogen for longer.