We identified a protein component of the intracellular mature vaccinia virion membrane that is a target of a potent neutralizing monoclonal antibody, 7D11, obtained from Alan L Schmaljohn. By immunofluorescent and electron microscopic analysis, MAb 7D11 was found to stain intracytoplasmic viral factories, virion membranes in cell sections, and the surface of negatively stained preparations of purified virions. The MAb 7D11 antigen, which is synthesized at late times in infection, has apparent molecular masses of 25 and 29 kDa under nonreducing and reducing conditions, respectively. The membrane antigen was most efficiently extracted from virions by NP40 detergent in combination with a reducing agent; in addition, the protein partitioned exclusively into the detergent phase when extracted with Triton X-114. Although the N-terminus of the immunoaffinity-purified protein was blocked, sequence analysis of trypic peptides revealed that the MAb 7D11 antigen was identical to the myristylated protein encoded by the L1R open reading frame previously described by C.A. Franke, E.M. Wilson, and D.E. Hruby (1990, J. Virol. 64, 5988-5996). Validation of this genetic assignment was provided by the ability of MAb 7D11 to immunoprecipitate a [3H]myristic acid-labeled product of the expected molecular weight from infected cells. In addition, we discovered that the previously described neutralizing monoclonal antibody 2D5 (Y. Ichihashi, T. Takahashi, and M. Oie, 1994, Virology 202, 834-843) also recognizes the L1R protein.

The radioprotective and behavioral effects of an acute administration of the isoflavone genistein (4',5,7-trihydroxyflavone) were investigated in adult CD2F1 male mice. Mice were administered a single subcutaneous (s.c.) dose of genistein either 24 h or 1 h before a lethal dose of gamma radiation (9.5-Gy of cobalt-60 at 0.6 Gy min(-1)). Mice received saline, PEG-400 vehicle or genistein at 3.125, 6.25, 12.5, 25, 50, 100, 200, or 400 mg kg(-1) body weight. For mice treated 24 h before irradiation there was a significant increase in 30-day survival for animals receiving genistein doses of 25 to 400 mg kg(-1) (p<0.001). In contrast, the 30-day survival rates of mice treated with genistein 1 h before irradiation were not significantly different from those of the vehicle control group. Additionally, the acute toxicity of genistein was evaluated in non-irradiated male mice administered a single s.c. injection of saline, vehicle, or genistein at 100, 200 or 400 mg kg(-1). At these genistein doses there were no adverse effects, compared with controls, on locomotor activity, grip strength, motor coordination, body weight, testes weight, or histopathology. These results demonstrate that a single s.c. administration of the flavonoid genistein at non-toxic doses provides protection against acute radiation injury.

δ-Tocotrienol (DT3), a vitamin E isoform, is associated with strong antioxidant and immunomodulatory properties. We confirmed the potent antioxidant activity in membrane systems and showed that DT3 is an effective radiation protector and mitigator. DT3 (4 μM, P < 0.001) inhibited lipid peroxidation in mouse liver microsomes and nitric oxide (NO) formation (20 μM DT3, P < 0.01) in RAW264.7 cells, a murine alveolar macrophage line. In CD2F1 mice exposed to lethal total-body radiation from a (60)Co γ-radiation source, a single subcutaneous (s.c.) injection of DT3 before or after irradiation produced a significant increase in 30-day survival. DT3 was effective from 18.75 to 300 mg/kg (--24 h, P < 0.001). A single dose of 150 or 300 mg/kg DT3 given 24 h before irradiation (radioprotection) resulted in dose reduction factors (DRFs) of 1.19 and 1.27, respectively (P < 0.001). Further, DT3 reduced radiation lethality when administered 2, 6 or 12 h after irradiation, and 150 mg/kg DT3 administered 2 h after exposure conferred a DRF of 1.1 (mitigation). The optimum schedule of 300 mg/kg DT3 24 h prior to 7 Gy significantly reduced pancytopenia compared to irradiated controls (P < 0.05). The large therapeutic potential of and multi-lineage hematopoietic recovery for DT3 warrants further studies.

The onlive version of this article has a Supplementary Appendix. BackgroundExposure to g-radiation causes rapid hematopoietic cell apoptosis and bone marrow suppression. However, there are no approved radiation countermeasures for the acute radiation syndrome. In this study, we demonstrated that natural d-tocotrienol, one of the isomers of vitamin E, significantly enhanced survival in total body lethally irradiated mice. We explored the effects and mechanisms of d-tocotrienol on hematopoietic progenitor cell survival after g -irradiation in both in vivo and in vitro experiments. Design and Methods CD2F1 mice and human hematopoietic progenitor CD34+ cells were treated with d-tocotrienol or vehicle control 24 h before or 6 h after g-irradiation. Effects of d-tocotrienol on hematopoietic progenitor cell survival and regeneration were evaluated by clonogenicity studies, flow cytometry, and bone marrow histochemical staining. d-tocotrienol and g-irradiation-induced signal regulatory activities were assessed by immunofluorescence staining, immunoblotting and short-interfering RNA assay. + cells from radiation-induced damage. d-tocotrienol activated extracellular signal-related kinase 1/2 phosphorylation and significantly inhibited formation of DNA-damage marker g-H2AX foci. In addition, d-tocotrienol up-regulated mammalian target of rapamycin and phosphorylation of its downstream effector 4EBP-1. These alterations were associated with activation of mRNA translation regulator eIF4E and ribosomal protein S6, which is responsible for cell survival and growth. Inhibition of extracellular signalrelated kinase 1/2 expression by short interfering RNA abrogated d-tocotrienol-induced mammalian target of rapamycin phosphorylation and clonogenicity, and increased g-H2AX foci formation in irradiated CD34 + cells. ConclusionsOur data indicate that d-tocotrienol protects mouse bone marrow and human CD34 + cells from radiation-induced damage through extracellular signal-related kinase activation-associated mammalian target of rapamycin survival pathways.Key words: g-tocotrienol, radioprotection, Erk, mTOR. Haematologica 2010;95(12):1996. doi:10.3324/haematol.2010 This is an open-access paper. © F e r r a t a S t o r t i F o u n d a t i o n

We aim to develop a rapid, easy-to-use, inexpensive and accurate radiation dose-assessment assay that tests easily obtained samples (e.g., blood) to triage and track radiological casualties, and to evaluate the radioprotective and therapeutic effects of radiation countermeasures. In the present study, we evaluated the interleukin (IL)-1 family of cytokines, IL-1β, IL-18 and IL-33, as well as their secondary cytokines’ expression and secretion in CD2F1 mouse bone marrow (BM), spleen, thymus and serum in response to γ-radiation from sublethal to lethal doses (5, 7, 8, 9, 10, or 12 Gy) at different time points using the enzyme-linked immune sorbent assay (ELISA), immunoblotting, and cytokine antibody array. Our data identified increases of IL-1β, IL-18, and/or IL-33 in mouse thymus, spleen and BM cells after total-body irradiation (TBI). However, levels of these cytokines varied in different tissues. Interestingly, IL-18 but not IL-1β or IL-33 increased significantly (2.5–24 fold) and stably in mouse serum from day 1 after TBI up to 13 days in a radiation dose-dependent manner. We further confirmed our finding in total-body γ-irradiated nonhuman primates (NHPs) and minipigs, and demonstrated that radiation significantly enhanced IL-18 in serum from NHPs 2–4 days post-irradiation and in minipig plasma 1–3 days post-irradiation. Finally, we compared circulating IL-18 with the well known hematological radiation biomarkers lymphocyte and neutrophil counts in blood of mouse, minipigs and NHPs and demonstrated close correlations between these biomarkers in response to radiation. Our results suggest that the elevated levels of circulating IL-18 after radiation proportionally reflect radiation dose and severity of radiation injury and may be used both as a potential biomarker for triage and also to track casualties after radiological accidents as well as for therapeutic radiation exposure.