Acute Effects of Iron-Particle Radiation on Immunity. Part II: Leukocyte Activation, Cytokines and Adhesion

The effects of high-linear energy transfer (LET) radiation on immune function have not been clearly established. The major goal of this study was to evaluate leukocyte responses after whole-body exposure to high-LET radiation. C57BL/6 mice were exposed to 0, 0.5, 2 and 3 Gy super(56)Fe super(26+) pa...

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Bibliographic Details
Published in:Radiation research 2006-01, Vol.165 (1), p.78-87
Main Authors: Gridley, D S, Dutta-Roy, R, Andres, M L, Nelson, G A, Pecaut, MJ
Format: Article
Language:English
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Summary:The effects of high-linear energy transfer (LET) radiation on immune function have not been clearly established. The major goal of this study was to evaluate leukocyte responses after whole-body exposure to high-LET radiation. C57BL/6 mice were exposed to 0, 0.5, 2 and 3 Gy super(56)Fe super(26+) particles (1055 MeV/nucleon, 148.2 keV/ mu m) and killed humanely 4 days after exposure. Spontaneous synthesis of DNA in blood and spleen cells was increased significantly in groups receiving either 2 or 3 Gy (P < 0.001). In contrast, a significant depression in the response of T lymphocytes to phytohemagglutinin (PHA) and concanavalin A (ConA) was noted (P < 0.005); the response to lipopolysaccharide (LPS), a B-cell mitogen, was similar among groups. A cytometric bead array assay revealed that the level of tumor necrosis factor alpha (Tnfa) secreted by splenocytes increased significantly with increasing super(56)Fe-particle dose (P < 0.05); interferon gamma , interleukin2 (Il2), Il4 and Il5 were unaffected. Flow cytometry analysis showed that 2 and 3 Gy markedly reduced splenic mononuclear cells expressing the activation markers CD25 and CD71, both with and without the T-cell marker CD3 (P < 0.05); proportions also varied significantly. Similar patterns were noted in mononuclear and granular cells with adhesion markers CD11b and, to a lesser extent, CD54 (P < 0.05). The results show that a single, acute exposure to high-LET radiation induced changes that can profoundly alter leukocyte functions. The implications of the data are discussed in relation to low-LET radiation, altered gravity, and space flight.
ISSN:0033-7587
DOI:10.1043/0033-7587(2006)165[0078:AEOIRO]2.0.CO;2