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Title: Low Dose Ionizing Radiation Modulates Immune Function

In order to examine the effects of low dose ionizing radiation on the immune system we chose to examine an amplified adaptive cellular immunity response. This response is Type IV delayed-type hypersensitivity also called contact hypersensitivity. The agent fluorescein isothiocyanate (FITC) is a low molecular weight, lipophilic, reactive, fluorescent molecule that can be applied to the skin where it (hapten) reacts with proteins (carriers) to become a complete antigen. Exposure to FITC leads to sensitization which is easily measured as a hypersensitivity inflammatory reaction following a subsequent exposure to the ear. Ear swelling, eosinophil infiltration, immunoglobulin E production and cytokine secretion patterns characteristic of a “Th2 polarized” immune response are the components of the reaction. The reaction requires successful implementation of antigen processing and presentation by antigen presenting Langerhans cells, communication with naïve T lymphocytes in draining lymph nodes, expansion of activated T cell clones, migration of activated T cells to the circulation, and recruitment of memory T cells, macrophages and eosinophils to the site of the secondary challenge. Using this model our approach was to quantify system function rather than relying only on indirect biomarkers of cell. We measured the FITC-induced hypersensitivity reaction over a range of doses frommore » 2 cGy to 2 Gy. Irradiations were performed during key events or prior to key events to deplete critical cell populations. In addition to quantifying the final inflammatory response, we assessed cell populations in peripheral blood and spleen, cytokine signatures, IgE levels and expression of genes associated with key processes in sensitization and elicitation/recall. We hypothesized that ionizing radiation would produce a biphasic effect on immune system function resulting in an enhancement at low doses and a depression at higher doses and suggested that this transition would occur in the dose range of 5 to 50 cGy.« less
Authors:
 [1]
  1. Loma Linda Univ., CA (United States)
Publication Date:
OSTI Identifier:
1234698
Report Number(s):
DOE/ER-64787--1033233-0015382
TRN: US1600227
DOE Contract Number:
SC0001832
Resource Type:
Technical Report
Research Org:
Loma Linda University, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; EOSINOPHILS; LYMPHOCYTES; IMMUNOGLOBULINS; AUDITORY ORGANS; IONIZING RADIATIONS; FLUORESCEIN; MACROPHAGES; INFLAMMATION; ANTIGENS; ISOTHIOCYANATES; SKIN; SPLEEN; SWELLING; GENES; IMMUNITY; MILLI GY RANGE; GY RANGE; BIOLOGICAL RADIATION EFFECTS; RADIOSENSITIVITY; IMMUNITY Low dose immune function