Vaccination is one of the best examples of successful manipulation of the immune system. However, vaccination against pathogens like influenza that have a high mutation rate, display variable antigens, and require T cell immunity are still tenuous. The immune system is made up of a diverse collection of cells, each of which has distinct sets of triggers that elicit unique and overlapping responses. Effector, Memory and Tolerant states of CD8 T cells all emerge from a different set of multiple interactions regulated i space and time. Mapping those interactions during natural infection and vaccination and understanding which ones are regulating T cell fate are essential to understand how immune balance is maintained. We hypothesize that specific cell interactions regulate long-term protection and can be manipulated during vaccination. We and others have recently used live imaging to demonstrate that T cell priming takes place in the limited physical volume of the 'reactive' lymph node under highly dynamic conditions that would appear to permit considerable mixing of ongoing responses. A key finding is that there is a 'Critical Differentiation Period' tha coincides with individual activated T cell clones coming together forming a T cell niche environment. We propose to develop a new imaging technique based on fluorescent barcoding of individual T cell clones coupled with organ-clearing to increase our knowledge of the niche-dependent regulation of T cell fate. This method will be the first imaging technique to give access to single-cell behavior over time, as opposed to current methods characterizing the behavior of a population. It will rely on the expression of a unique set of fluorescent proteins in each cell within an immune population of interest. Using whole Lymph Nodes imaging coupled to fluorescent barcoding, we will specifically investigate how T cell niches are formed and for how long they persist. T cell niches are platforms where contact-dependent signals regulate CD8 T cell differentiation and so understanding interactions here will affect multiple disorders. This information will give novel information on CD8 T cell fate that will be critical to enhance vaccination against viruses.
Vaccination is the best example of successful manipulation of the immune system, however, the control of some pathogens, like influenza, remain tenuous and therefore requires a deeper understanding of how long- term protection is achieved. Using and developing advanced imaging methods, this project will provide a comprehensive characterization of the mechanisms regulating a 'niche' environment crucial for T cell long-term memory generation during vaccination.
| Krummel, Matthew F; Mahale, Jagdish N; Uhl, Lion F K et al. (2018) Paracrine costimulation of IFN-? signaling by integrins modulates CD8 T cell differentiation. Proc Natl Acad Sci U S A 115:11585-11590 |
| Krummel, Matthew F; Bartumeus, Frederic; Gérard, Audrey (2016) T cell migration, search strategies and mechanisms. Nat Rev Immunol 16:193-201 |
