Emma Dehm

Long-lived effector cells (LLEC) are a subset of memory CD8+ T cells that express uniquely high levels of some natural killer-associated receptors, such as NKG2A and NK1.1. These receptors are called NK-associated receptors because they are traditionally expressed on the surface of NK cells, and are considered activating or inhibitory based on their effect on the immune response. LLEC are the preferred subset to respond to Listeria monocytogenes (LM) infection, possibly because increased expression of NK-associated receptors gives LLEC an improved ability to respond to infection by impacting their capacity to produce cytotoxic molecules. To explore this possibility, we assessed the quantity of each NK-associated receptor on the surface of LLEC throughout the course of infection. We found that NKG2A and CD94, which form an inhibitory functional heterodimer, were expressed highly on LLEC throughout the time-course. We hypothesize that knockout of the Klrc1 and Klrd1 genes (encode NK-associated receptors NKG2A and CD94, respectively) with CRISPR/Cas9 will result in greater cytokine production compared to wild-type controls. We set up two experimental groups, consisting of mice that received congenically-distinct Klrc1 or Klrd1 knockout CD8+ T cells (n=5) and a negative control (n=3). As expected, we observed heightened cytokine production upon peptide stimulation in the Klrd1 knockout LLEC compared to the control. Further analyses are ongoing, but will involve knocking out all inhibitory NK-associated receptors to study effects on LLEC function. If successful, these inhibitory NK-associated receptors could be a new target for study of LLEC-mediated cytotoxicity at the onset of systemic infection.