Interaction of Accelerated Low-Energy Electrons with Immune Cells

Electron beam technology, based on accelerated electrons, is increasingly used in biological applications. Here, the impact of increasing doses of Low-Energy Electron Irradiation (LEEI) on the human leukemic T-cell line Jurkat was tested. By varying the irradiation parameters, different cellular effects were achieved. Using the OPP-System as experimental setup, combined with an acceleration voltage of 200 keV, Jurkat cells were treated with doses ranging from 50 Gy to 250 Gy. The irradiated cells were retrieved, and several distinctive targets of the ionizing radiation were examined.

A reduction of the cellular viability, metabolism, and mitochondrial membrane potential (ΔΨM) was observed in a dose-dependent way. Cell cultures treated with 108 Gy to 142 Gy were able to partially restore their viability and ΔΨM within the subsequent 192-h cultivation period.

Analysis of the cell cycle did not reveal arrest of the cell cycle phases due to the high doses applied. Nevertheless, parallels to the findings of the assessed cellular viability and ΔΨM were found. While samples with doses above 180 Gy predominantly went into apoptosis, cell cultures irradiated with up to 150 Gy were able to restore their cell cycle to a certain extent.

Assessment of radiation-induced DNA damage by Comet- Assay and immunofluorescent marking of histone γ-H2AX, revealed an increase of DNA strand breaks immediately after irradiation. Instead of repairing the lesions, they progressively increased in all irradiated samples after 48 h.

In conclusion, we have found that high doses of LEEI impair functional properties of T-cells in a dose - dependent manner.