Radiation damage and immune suppression in splenic mononuclear cell populations

Abstract

SUMMARYWe have examined alterations in all of the major splenic mononuclear cell (SMNC) populations in C57Bl/6 mice following whole-body irradiation (0-700 cGy) in order to determine which populations may play a role in active immune suppression and/or haematopoietic recovery. A protocol has been established for characterization and differentiation by flow cytometric analysis (FCA) of the major MNC populations in the mouse spleen: T lymphocytes (CD4 + and CD8 + cells), B lymphocytes, natural killer (NK) cells, and monocytes/macrophages. Ionizing radiation caused decreased spleen cellularity and decreased ability of surviving SMNC to respond to mitogen. FCA revealed alterations in the relative composition of the constituent splenic cell populations following irradiation, reflecting differential radiosensitivity, with selective enrichment of NK cells (seven-fold) and CD4 + T lymphocytes (threefold). Enrichment developed during the 7-day post-irradiation period. In addition, some MNC became activated in a dose-and time-dependent fashion following whole-body irradiation, as indicated by expression of CD71, the transferrin receptor. These cells were CD34 + and Thy1.2 + , but were CD4 ¹ or CD8 ¹ as well as CD45

The Effects of Low-dose Ionizing Radiation in the Activated Rat Basophilic Leukemia (RBL-2H3) Mast Cells

“…The immune-suppressing effects of high-dose radiation have been clearly demonstrated and confirmed both experimentally and in epidemiological studies (1,2). However, the effects of lowdose ionizing radiation on the immune system remain controversial.…”

“…Mast cells express high-affinity IgE receptors, Fc⑀RI, 2 on their surfaces that mediate their immunological activities (11)(12)(13). Cross-linking of Fc⑀RI-bound IgE with multivalent antigens initiates the activation of mast cells by promoting the aggregation of Fc⑀RI (11).…”

“…Cells were cultured in Eagle's minimum essential medium (GIBCO) containing 15% FBS (GIBCO) and maintained at 37°C in a humidified incubator containing 95% air and 5% CO 2 .…”

Radiosensitivity of peripheral blood B cells in pigs

“…The lymphoid compartment of peripheral blood leukocytes is famed for its high radiosensitivity (Harrington et al, 1997;Chambers et al, 1998) and has thus been investigated as a possible source of useful biomarkers (Gridley et al, 2002). Differences in the radiosensitivity of lymphocyte populations, subpopulations and subsets have been used for biodosimetric purposes (Crompton and Ozsahin, 1997;Harrington et al, 1997;Mori et al, 2005).…”

“…Differences in the radiosensitivity of lymphocyte populations, subpopulations and subsets have been used for biodosimetric purposes (Crompton and Ozsahin, 1997;Harrington et al, 1997;Mori et al, 2005). The higher radiosensitivity of B cells over T cells has been documented in mice (Anderson et al, 1977;Durum and Gengozian, 1978), rats and humans (Schwartz et al, 1983;Ashwell et al, 1986).…”