Determining factors of inflammation that support the expansion and function of long-lived effector cell CD8 T cells in a mature memory compartment

PROJECT SUMMARY/ABSTRACT The use of specific pathogen free (SPF) mice has been instrumental in the advancement of immunological research, reducing variability between experiments and institutions. However, it is becoming increasingly evident that pathogen experience alters the immune system dramatically. This limits the translation potential of

discoveries in SPF mice, as humans are regularly exposed to pathogens from birth. Work from the Hamilton lab and others has found that increasing the microbial exposure of mice through pet shop mouse cohousing (COH) alters the immune compartment of mice to more accurately reflect that of an adult human. This change

is particularly evident in the memory CD8 T cell compartment. The CD8 T cell memory pool contains cells with a wide range of trafficking patterns, effector functions, and longevity. In SPF mice, the CD8 T cell compartment is dominated by naïve cells and central memory T cells. However, COH mice and adult humans contain

predominantly effector memory T cells, including long-lived effector cells (LLEC), a population described by the Hamilton Lab. This proposal aims to understand how pathogen exposure and inflammation lead to the expansion and maintenance of LLEC, and how the expansion of this cell population alters the overall function

of the T cell compartment. Aim 1 will determine what proinflammatory cytokines support LLEC formation and persistence. Experiments will identify cytokines and other factors that lead to the increase in LLEC during COH, via the use of RNA sequencing and CRISPR mediated genetic knockouts. We will also determine if we

can expand LLEC in the absence of pathogen exposure via administration of cytokines. Aim 2 will determine how COH alters the function of LLEC, and address the consequences of skewing the memory compartment to LLEC for responses to systemic and local infections. This aim will utilize adoptive cell transfers and an

inducible fluorescent reporter to determine if COH LLEC can protect against systemic and local infections. Focusing on CD8 T cell memory, and incorporating RNA sequencing analysis, will support goals 1 and 2 of my training plan, and the proposal will develop my skills as an academic scientist as a whole (training aim 3). The

Center for Immunology at the University of Minnesota is an ideal environment to complete this proposal as there is a strong record of impactful immunological research and postdoctoral training, particularly within T cell biology. Altogether, these studies will yield critical information regarding the importance of pathogen exposure

and inflammation on the memory T cell compartment, as well as novel information on the functionality of subsets of memory CD8 T cells. These data will be useful to develop vaccines and T cell therapies with increased translation potential.