Characterizing the Mechanical Changes of CD8+ T cells

Abstract

The adaptive immune system is comprised of many types of white blood cells that clear pathogens from the body by promoting an inflammatory response. CD8+ T cells are an integral part of this process, as they exclusively induce apoptosis in infected cells and pathogens that invade the body. Much is known about the changes that accompany a CD8+ T cell when it is initially activated and re-activated by antigens. However, the mechanical changes that occur during these stages of activation have not yet been investigated. In this study, CD8+ T cells were activated using anti-CD3 particles and Dynabeads and later re-activated with the same stimulant. Mechanical changes were assessed with Atomic Force Microscopy (AFM). It was hypothesized that activation would cause the T cells to become softer, and that re-activation would cause the cells to become stiffer. It was also hypothesized that Dynabeads would cause a more complete activation of the cells as compared to the anti-CD3 particles. Results revealed that activation causes CD8+ T cells to soften (CD3: p=3.14e-17, Dyna: p=9.99e-14, but only confirmed that the T cells became stiffer after re-activation with anti-CD3 particles (p= 0.002). Additionally, it was observed that anti-CD3 particles cause a larger mechanical change after activation than stimulation with Dynabeads (p=0.00983).