Gamma radiation induces CD69 expression on lymphocytes

Abstract

Gamma radiation activates protooncogenes that are involved in early signal transduction, e.g., Raf-1. Most studies of effects of gamma radiation on lymphocytes deal with regulation of gene expression. However, early surface receptor expression in response to radiation has not been reported. We studied the effect of radiation on lymphocyte CD69 expression and BrdU uptake in the absence or presence of phytohemagglutinin (PHA). Radiation induces CD69 expression on T and B cells in a dose-and time-dependent manner. Four hours after a dose of 906 cGy, approximately 90% of B and 12% of T cells express CD69. CD69 expression diminishes after 6 h and requires de novo protein synthesis and protein phosphorylation. Radiation alone does not stimulate cell proliferation, as measured by BrdU incorporation, at any radiation dose tested. Furthermore, radiation enhances PHA induced CD69 expression at 2 h, but inhibits BrdU incorporation at day 3 in a dose-dependent fashion. CD69 functions as a marker for response to radiation, but unlike antigen or mitogen, radiation-induced CD69 expression does not lead to proliferation.

Assessment of donor T‐cell function in cellular blood components by the CD69 induction assay: effects of storage, γ radiation, and photochemical treatment

“…A practical application of the CD69‐induction assay in transfusion medicine may be rapid confirmation of T‐cell inactivation by treatments designed to prevent GVHD. While low doses of gamma radiation upregulate CD69 expression, 43 we show here that the PMA responsiveness of passenger T cells in gamma‐radiated or photochemically treated PCs is severely suppressed shortly after exposure at levels recommended for GVHD prophylaxis. The phenomenon that a minority of T cells in the treated components still responded with upregulation of CD69 after PMA stimulation, albeit at a lower level than in the controls, has been observed previously during irradiation experiments 8 and has been attributed to physiologically weak stimulation by the mitogen 44 .…”

Exposure to Low to Moderate Doses of Ionizing Radiation Induces A Reduction of Pro-Inflammatory Ly6chigh Monocytes and a U-Curved Response of T Cells in APOE -/- Mice

“…50,51 In contrast, Tregs were significantly increased following irradiation in mice affected with arthritis, 52 asthma, 53 or prostate cancer. 54 Likewise, many, 46,55 but not all 56 low dose radiation studies report enhanced CD69 þ activated T cells. Regardless, our findings do not support a predominant role for regulatory or CD69 þ T cells in the response to LDIR in the context of atherosclerosis.…”

Low dose radiation induced immunomodulation: Effect on macrophages and CD8+T cells

“…In contrast, exposure to high doses of ionizing radiation (906 cGy) in vitro has been reported to induce the expression of CD69 in human peripheral blood lymphocytes but did not result in enhanced proliferation (Chen et al 1997). The precise role of CD69 in immunity has not been elucidated owing to the absence of a known ligand and adequate in vivo models to study its physiological function but it has been used as a marker for cellular activation (Sancho et al 2005).…”