3.5. Investigations of the immune status of animal models exposed to magnetic fields

Project management: Fraunhofer ITEM, Hannover
Start: 1 December 2016
End: 30 September 2019

Background

From a biophysical perspective, the energy of low-frequency magnetic fields (ELF-MF) is not sufficient to directly damage DNA and thus directly cause cancers such as leukaemia. However, three independent studies in CD1 mice or a transgenic mouse model consistently showed decreased numbers of immune cells in the blood counts of the young after up to 90 days of ELF-MF exposure. The transgenic mouse model replicates precursor B-cell ALL by mimicking the common chromosomal translocation ETV6/RUNX1. This is specific for B-ALL (acute lymphoblastic (B-cell) leukaemia). B-ALL is the most common form of childhood leukaemia.

Objectives

So far, there is no evidence that the reduction of immune cells in the developing immune system is a mandatory step for the manifestation of B-ALL. Based on the aforementioned indications, the present project aims to investigate changes in the phenotype and function of immune cells in a suitable mouse model for B-ALL in children exposed to magnetic fields. The effect of pre- and postnatal exposure to low-frequency magnetic fields in young mice will be tested by blood and immune cell studies in comparison with both sham-exposed and cage control animals. The focus is on characterising a possibly weakened or deficient immune system. Examinations on haematology, immunohistopathology, immune status and immunophenotyping will be performed in various organs such as blood, spleen, bone marrow, and thymus.

Implementation

Sca1-ETV6-RUNX1 mice, which carry the relatively common leukaemia-specific mutation ETV6/RUNX1 in their genome, will be used as animal models. Twenty male and twenty female young will be specifically examined for changes in their immune status at 7, 14, and 28 days after birth. Exposure to 50 Hertz magnetic fields will be carried out in utero one day after the onset of pregnancy in three identical exposure facilities with magnetic flux densities of 10 µT and 1 mT as well as sham exposure. The animals will be exposed 20 h a day, 7 days a week. In addition, a cage control group will be included for each study time point (7, 14, and 28 days).

The exposure device used is a system developed by IMST GmbH, Kamp-Linfort. This was already used at Fraunhofer ITEM in a previous project ^[1]. The three identical facilities (i.e. also for the sham exposure group) will enable a blinded study.

¹ For more information on the exposure system used in this project, see Annex 1 of the BfS study Influence of low-frequency electromagnetic fields on the developing haematopoietic system, the immune system, and the CNS in vivo.