Medical/biological study (experimental study)

Reversible effect of magnetic fields on human lymphocyte activation patterns: different sensitivity of naive and memory lymphocyte subsets med./bio.

By: Salerno S, La Mendola C, La Manna MP, Casto AL, Caccamo N, Salerno A

Published in: Radiat Res 2009; 172 (4): 444-450

Aim of study (acc. to author)

To study the effect of 50 Hz magnetic field or static magnetic fields of 0.5 mT on subsets of human CD4⁺ T cells (CD4⁺ CD45RA⁺ T cells and CD4⁺ CD45RA^--T cells) in terms of cytokine release, cell proliferation and intracellular free calcium concentration after 24 and48 h of cell culture. Subsets that were more sensitive to the effects of the magnetic fields should be identified.

Background/further details

CD4⁺ T cells can be divided into different subsets on the basis of surface marker expression (e.g. CD45), and T cells can be divided into naive (CD45RA⁺) and memory (CD45RA^-) cells.
Blood samples were obtained from eight volunteers. The samples of the T cell subsets were also stimulated by PHA.

Endpoint

cell function: lymphocyte activation: cytokine release, cell proliferation and intracellular free calcium concentration

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 2 hr, 24 hr or 48 hr	magnetic flux density: 0.5 mT
Exposure 2: DC/static Exposure duration: continuous for 2 hr, 24 hr or 48 hr	magnetic flux density: 0.5 mT

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	continuous for 2 hr, 24 hr or 48 hr

Exposure setup

Exposure source	solenoid
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.5 mT	-	measured	-	-

Exposure 2

Main characteristics

Frequency	DC/static
Type	magnetic field
Exposure duration	continuous for 2 hr, 24 hr or 48 hr

Exposure setup

Exposure source	magnet
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.5 mT	-	measured	-	-

Exposed system:

intact cell/cell culture
human t-lymphocytes

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: cytokine release (interferon-gamma) from CD4⁺ T cells, CD4⁺ CD45RA⁺ T cells and CD4⁺ CD45RA^- T cells (ELISA)
cell function: number of CD45RA⁺ T cells and CD45RA^- T cells (negative selection via immunomagnetic beads; flow cytometry), percentage of IFN-gamma⁺ CD4⁺ CD45RA⁺ T cells and IFN-gamma⁺ CD4⁺ CD45RA^- T cells (intracellular staining; flow cytometry)
cell viability/cell division/proliferation: cell proliferation of the different T cell subsets (Ki-67 antigen staining; flow cytometry)
intracellular free calcium concentration (as indicator of cell viability/activation; intracellular staining via calcein antibody; flow cytometry)

Investigated system:

intact cell/cell culture
cell supernatants

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The data showed that 0.5 mT, 50 Hz magnetic fields or static magnetic fields (2 h exposure) induced a decrease in the release and content of interferon-gamma in CD4⁺ CD45RA^--T cell subset (compared to CD4⁺ CD45RA⁺ T cell subset). This alteration was more evident at 24 h (than at 48 h) for both magnetic fields. The release of interferon-gamma from exposed CD4⁺ CD45RA^--T cells was significantly decreased compared to that of sham-exposed CD4⁺ CD45RA^--T cells.
Flow cytometry analysis showed that the CD4⁺ CD45RA^--T cell population was the most sensitive to the magnetic fields (50 Hz or static magnetic fields). The content of interferon-gamma was significantly decreased in this subset after 24 h of exposure to the magnetic fields. However, this decrease was reversed after 48 h of cell culture.
A decrease in cell proliferation and intracellular free calcium concentrations from exposure to both magnetic fields in the CD4⁺ CD45RA^--T cell subset was also observed.
The data suggest that exposure to the magnetic fields induces a delay in the response to stimulants (PHA) and that modifications are rapidly reversible, at least after a short exposure (2 h). The results do not explain why both magnetic fields influence only one subset of the CD4⁺ T-cell population.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

University of Palermo, Italy

Fan W et al. (2015): 50 Hz electromagnetic field exposure promotes proliferation and cytokine production of bone marrow mesenchymal stem cells
Salehi I et al. (2013): Exposure of rats to extremely low-frequency electromagnetic fields (ELF-EMF) alters cytokines production
Bouwens M et al. (2012): Low-frequency electromagnetic fields do not alter responses of inflammatory genes and proteins in human monocytes and immune cell lines
de Kleijn S et al. (2011): Extremely low frequency electromagnetic field exposure does not modulate toll-like receptor signaling in human peripheral blood mononuclear cells
Salerno S et al. (2006): Reversible effect of MR and ELF magnetic fields (0.5 T and 0.5 mT) on human lymphocyte activation patterns
Di Giampaolo L et al. (2006): Follow up study on the immune response to low frequency electromagnetic fields in men and women working in a museum
Aldinucci C et al. (2003): The effect of strong static magnetic field on lymphocytes
Bonhomme-Faivre L et al. (2003): Effects of electromagnetic fields on the immune systems of occupationally exposed humans and mice
Boscolo P et al. (2001): Effects of low frequency electromagnetic fields on expression of lymphocyte subsets and production of cytokines of men and women employed in a museum
Salerno S et al. (1999): Static magnetic fields generated by a 0.5 T MRI unit affects in vitro expression of activation markers and interleukin release in human peripheral blood mononuclear cells (PBMC)

Reversible effect of magnetic fields on human lymphocyte activation patterns: different sensitivity of naive and memory lymphocyte subsets med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

Exposure 1

Main characteristics

Exposure setup

Parameters

Exposure 2

Main characteristics

Exposure setup

Parameters

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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