Katie Soden, Cameron Rankin, John Peller
Faculty Sponsor: Sophia Sarafova
Many factors influence the relative abundance of CD4+ helper vs CD8+ killer T cells in the body, however in the vast majority of mammals the CD4:CD8 ratio is maintained above one. Previous research at Davidson College has identified an inverted ratio (CD4:CD8<1) in the B10.A mouse strain housed in Davidson’s conventional mouse facility, while the B10 mice housed in the same facility have a normal ratio (CD4:CD8>1). In this project we investigated which T cell subsets contribute the most to this change in relative frequencies of CD4 and CD8 cells in the B10.A mice as compared to the B10 mice. Previous research determined that the B10.A mice have increased frequency of CD8 memory T cells while also having a decreased frequency of naive CD4 T cell populations. Therefore, we aim to identify if T cell memory populations contributed to the inverted CD4:CD8 ratio in the B10.A mice by classifying and enumerating the memory vs naïve CD4 and CD8 T cell populations in both mouse strains. Three male B10 and three male B10.A mice were chosen to be as close in age as possible in order to reduce confounding variables like age and sex differences during analysis, as both can impact the CD4/CD8 T cell ratio. The lymph nodes, excluding the mesenteric lymph nodes, were harvested and cell suspensions were prepared. To determine the frequency and number of the different memory populations we stained single cell suspensions from the lymph nodes of each mouse for the memory markers CD44 and CD62L and either CD4 or CD8. A viability stain was added to each sample and the stained cells were analyzed using flow cytometry. Here we report the differences in the T cell naive, effector memory, and central memory T cell populations we observed between the two mouse strains.