Nanostructural and biochemical property changes in activation-induced CD8+ T cell apoptosis utilizing AFM and Raman spectroscopy

Y.J. Lee, G.J. Lee, H.K. Park
Kyung Hee University,
Korea

Keywords: T cell activation, AFM, Raman spectroscopy, apoptosis

Summary:

This study was to investigate the changes in nanostructure and biochemical properties of activated mature CD8+ T cells related to apoptosis at a molecular level. We confirmed the activation and apoptosis of CD8+ T cells by fluorescence-activated cell sorting and atomic force microscopy (AFM) and then performed Raman spectral measurements on activated mature CD8+ T cells and cellular deoxyribose nucleic acid (DNA). From AFM images, the activated mature CD8+ T cells result in an increased cell volume and cell perimeter (that is, a more irregular rim shape) over that observed in resting CD8+ T cells. In the activated mature CD8+ T cells, there were increases in protein spectra at 1002 and 1234 cm−1. In particular, to assess the apoptosis related DNA spectral signatures, we investigated the spectra of the cellular DNA isolated from resting and activated mature CD8+ T cells. Raman spectra at 765 to 786 cm−1 and 1053 to 1087 cm−1 were decreased in activated mature DNA. In addition, we analyzed Raman spectrum using the multivariate statistical method including principal component analysis. Raman spectra of activated mature DNA are especially well-discriminated from those of resting DNA. Our findings regarding the biochemical and structural changes associated with apoptosis in activated mature T cells and cellular DNA according to Raman spectroscopy provide important insights into allospecific immune responses generated after organ transplantation, and may be useful for therapeutic manipulation of the immune response.