Influence of single nucleotide polymorphisms of cytokine genes on anti-HBs antibody production after hepatitis B vaccination in a Japanese young adult population

Hepatitis B (HB) vaccination is one of the most efficient tools to prevent the transmission of the virus. Considerable variability exists in HB vaccine responses, with 5-10% of healthy Japanese adults demonstrating no response following a standard vaccination. Recently, polymorphisms of immune-regulatory genes, such as cytokine genes, have been reported to influence the immune response to HB vaccine. The aim of this study was to investigate the underlying mechanisms of the genetic association between several cytokine gene polymorphisms and the immune response to HB vaccination in a Japanese population. One hundred and twenty three vaccinated young adults were classified according to the level of antibody-titer (anti-HBs). Single nucleotide polymorphism typing for IFN-γ(+874, 3’-UTR), IL-10 (−591, −819, −1082), and TNF-α(−308, −857), was accomplished using the PCR-RFLP or SSP-PCR method. The TNF-α(−857) CC type and the IL-10 (−1082) AG type were present more frequently in the low titer group than in the high titer group. The TNF-α(−857) CC type was found to be significantly associated with low response of serum anti-HBs. The anti-HBs antibody was not readily produced in the IL-10 (−1082) AG and TNF-α(−857) CC haplotype. Conversely, the antibody was readily produced in the IL-10 (−1082) AA and TNF-α(−857) CC haplotype, and the IL-10 (−1082) AA and TNF-α(−857) CT haplotype, suggesting a high likelihood of the IL-10 (−1082) AG type to be included in the low anti-HBs group, and high anti-HBs antibody production in those with the TNF-α(−857) CT type. These SNPs may produce ethnically-specific differences in the immune response to HB vaccine in the Japanese population

A Large X-ray Flare from a Single Weak-lined T Tauri Star TWA-7 Detected with MAXI GSC

We present a large X-ray flare from a nearby weak-lined T Tauri star TWA-7 detected with the Gas Slit Camera (GSC) on the Monitor of All-sky X-ray Image (MAXI). The GSC captured X-ray flaring from TWA-7 with a flux of $3\times10^{-9}$ ergs cm$^{-2}$ s$^{-1}$ in 2--20 keV band during the scan transit starting at UT 2010-09-07 18:24:30.The estimated X-ray luminosity at the scan in the energy band is 3$\times10^{32}$ ergs s$^{-1}$,indicating that the event is among the largest X-ray flares fromT Tauri stars.Since MAXI GSC monitors a target only during a scan transit of about a minute per 92 min orbital cycle, the luminosity at the flare peak might have been higher than that detected. At the scan transit, we observed a high X-ray-to-bolometric luminosity ratio, log $L_{\rm X}/L_{\rm bol}$ = $-0.1^{+0.2}_{-0.3}$; i.e., the X-ray luminosity is comparable to the bolometric luminosity. Since TWA-7 has neither an accreting disk nor a binary companion, the observed event implies that none of those are essential to generate such big flares in T Tauri stars.Comment: 4 pages, 2 figures, 1 table accepted for publication in PAS

The type of DSB by direct action of X-rays is different comparison with the DSB induced by indirect action

We examined the contributions of OH radical mediated indirect action of X-ray on cell killing of CHO cells to investigate whether the lethal damage by direct or indirect actions would correlate with DSB reparable capacities using NHEJ-deficient cells (xrs6). The contribution of indirect action on cell killing can be estimated from the maximum degree of protection by DMSO, and that for CHO and xrs6 cells were 77% and 49%, respectively. The percentages of living cells of CHO and xrs6 cells after 2 Gy were 38.4% and 1.0%, respectively. Fractional cell killing by direct action were 14.4% and 50.5%, and that by indirect action were 47.2% and 48.5%, respectively. These results imply that the lethal damage induced by direct action is mostly repaired by NHEJ repair pathway. HR repair system can operate on DSBs induced by indirect action of X-rays. However, xrs6 cells with absolute dependency on the HR were unable to rejoin the DSB induced by direct action leading to more pronounced cell killing than in CHO cells which have two complementary repair pathways. In other words, HR repair system could repair the DSB induced by indirect action in place of NHEJ repair system, although HR repair system could not repair sufficiently the DSB by direct action in place of NHEJ repair system.38th Annual Meeting of the European Radiation Research Societ

Tumor metastasis exposed to high-LET radiations

Purpose: The aim of this study is to clarify the effect of carbon ion beams (C-ion) on metastatic potential of melanoma in vitro and in vivo. Materials and Methods: A highly metastatic mouse malignant melanoma cell line B16/BL6 were maintained in RPMI-1640 medium supplemented with 10% FBS and antibiotics. [in vitro] Samples were prepared 2 days before and then irradiated with C-ions or X-rays. Surviving fractions were obtained using colony formation assay. Migration and invasion activity as metastatic potentials of the cells were examined using the Boyden-chamber method and the Matrigel invasion assay. [in vivo] The cells were implanted in right-leg of C57BL/6J mice at 1x106 cells/mouse 9-10 days before irradiation. Tumors were irradiated at the center of 6cm-SOBP of C-ions, or gamma-rays. Radiosensitivity for whole tumor was obtained by the tumor growth delay method, and that for individual cell in a tumor was obtained by an in vivo-in vitro assay. The metastatic effects were analyzed with the spontaneous lung metastasis model. The dose averaged LET values of carbon beams were approximately 50 keV/um.Results: [in vitro] Survival curves showed higher cytotoxic effects of C-ions compared with X-rays, and the RBE values were 1.96. The potential of migration and invasion were suppressed by C-ions at all dose points (0.50 to 8.0 Gy) tested, however it was enhanced by X-rays at low dose points (0.50 and 1.0 Gy) than non-irradiated controls. The RBE values obtained from migration and invasion test were higher than that from cell killing. [in vivo] C-ions significantly suppressed the tumor growth, and the RBE was 2.64. The numbers of lung metastatic nodules after tumor-irradiations decreased with the dose, and C-ions were more effective compared with gamma-rays. The metastatic potentials of survived cells in a tumor after irradiation was analyzed with the number of metastatic lung colony from implanted tumors and survival of irradiated and explanted cells from a tumor. Smaller number of metastasis was found for C-ions than gamma-rays when the numbers were compared with biological equivalent dose. Conclusion: It might suggest that C-ion inhibit metastasis at radiotherapy compared with low-LET photons.NIRS-KI Joint Symposium on Carbon Ion Therap

The effects of heavy-ion and photon beams to mouse malignant melanoma cell line having highly metastatic potential

Purpose: Up to 2009, over 5000 patients have been treated in HIMAC. Malignant melanoma showed high local control of about 75%, whereas the overall survival was about 36% at 5-years. It is an important subject to control tumor distant metastasis for heavy-ion radiotherapy. The aim of this study is to clarify the effect of carbon ion beams (C-ion) on metastatic potential of melanoma in vitro and in vivo. Materials and Methods: A highly metastatic mouse malignant melanoma cell line B16/BL6 were maintained in RPMI-1640 medium supplemented with 10% FBS and antibiotics. [in vitro] Samples were prepared 2 days before and then irradiated with C-ions at 13, 50 or 75 keV/um or X-rays. Surviving fractions were obtained using colony formation assay. Migration and invasion activity as metastatic potentials of the cells were examined using the Boyden-chamber method and the Matrigel invasion assay. [in vivo] The cells were implanted in right-leg of C57BL/6J mice at 1x106 cells/mouse 9-10 days before irradiation. Tumors were irradiated at the center of 6cm-SOBP of C-ions, or gamma-rays. Radiosensitivity for whole tumor was obtained by the tumor growth delay method, and that for individual cell in a tumor was obtained by an in vivo-in vitro assay. The metastatic effects were analyzed with the spontaneous lung metastasis model. Results: [in vitro] Survival curves showed higher cytotoxic effects of C-ions compared with X-rays, and the RBE values were 1.1, 1.7 or 2.5 at 13, 50, or 75 keV/um, respectively. The potential of migration and invasion were suppressed by C-ions at all dose points (0.25 to 8.0 Gy) tested, however it was enhanced by X-rays at low dose points (0.25 to 0.5Gy) than non-irradiated controls. The RBE values obtained from migration and invasion test were higher than that from cell killing. [in vivo] C-ions significantly suppressed the tumor growth, and the RBE was 2.6. The numbers of lung metastatic nodules after tumor-irradiations decreased with the dose, and C-ions were more effective compared with gamma-rays. The metastatic potentials of survived cells in a tumor after irradiation was analyzed with the number of metastatic lung colony from implanted tumors and survival of irradiated and explanted cells from a tumor. Smaller number of metastasis was found for C-ions than gamma-rays when the tumor cell survivals were 10%. Conclusion: It might suggest that C-ion inhibit metastasis at radiotherapy compared with low-LET photons.PTCOG 4

Contribution of indirect action of X-irradiation under oxic and hypoxic conditions in different radiosensitivity cells

We examined the contribution of indirect action of X-irradiation under oxic and hypoxic conditions in cell killing of a CHO line and its NHEJ-defective xrs6 mutant line (a Ku80 mutant of CHO). X-irradiation was performed at a dose rate of 4.9 Gy/min using a generator operating at 200 kVp and 20 mA. For oxic and hypoxic conditions, irradiation chambers were flushed for more than 1 hour with air + 5% CO2 and 95% N2 + 5% CO2, respectively, prior to irradiation at room temperature. Protective effect of DMSO which specifically scavenges OH radicals was evaluated from cell survivals. Fractions of cell killing by the OH mediated indirect action were calculated by the method of Shinohara et al. (Acta Oncol., 35, 869-75. 1996). The fractions for CHO were 80% and 60% under oxic and hypoxic conditions, respectively. The fractions for xrs6 were 50% and 30% under oxic and hypoxic conditions, respectively. Thus, our data indicate that the indirect action of OH radicals in cell killing is dependent of the oxygen concentration and the repair capacity of the cells. However, radiolysis study of liquid water demonstrated previously that the G(OH) value was independent of oxygen concentration (C. V. Sonntag, The Chemical Basis of Radiation Biology, 33. 1987). When the repair proficient and deficient cells were compared, the contribution of the indirect action in cell killing was higher for the former than for the latter. In other words, the contribution of direct action was more pronounced in xrs6 cells. When the actual numbers of damages contributing for the cell killing were estimated, it was found that the repair deficient cells were more sensitive to the damage produced under hypoxia. It is our hypothesis that DNA damage produced under hypoxia is more complex and less likely to be repaired. This type of damage is especially problematic for NHEJ deficient xrs6 cells. Taken together, DNA damage due to direct action of X-rays was more akin to those by high LET radiations.10th International Workshop Radiation Damage to DN

Contribution of indirect action of X-irradiation under oxic and hypoxic conditions in different radiosensitivity cells

We examined the contribution of indirect action of X-irradiation under oxic and hypoxic conditions in cell killing of a CHO line and its NHEJ-defective xrs6 mutant line (a Ku80 mutant of CHO). X-irradiation was performed at a dose rate of 4.9 Gy/min using a generator operating at 200 kVp and 20 mA. For oxic and hypoxic conditions, irradiation chambers were flushed for more than 1 hour with air + 5% CO2 and 95% N2 + 5% CO2, respectively, prior to irradiation at room temperature. Protective effect of DMSO which specifically scavenges OH radicals was evaluated from cell survivals. Fractions of cell killing by the OH mediated indirect action were calculated by the method of Shinohara et al. (Acta Oncol., 35, 869-75. 1996). The fractions for CHO were 80% and 60% under oxic and hypoxic conditions, respectively. The fractions for xrs6 were 50% and 30% under oxic and hypoxic conditions, respectively. Thus, our data indicate that the indirect action of OH radicals in cell killing is dependent of the oxygen concentration and the repair capacity of the cells. However, radiolysis study of liquid water demonstrated previously that the G(OH) value was independent of oxygen concentration (C. V. Sonntag, The Chemical Basis of Radiation Biology, 33. 1987). When the repair proficient and deficient cells were compared, the contribution of the indirect action in cell killing was higher for the former than for the latter. In other words, the contribution of direct action was more pronounced in xrs6 cells. When the actual numbers of damages contributing for the cell killing were estimated, it was found that the repair deficient cells were more sensitive to the damage produced under hypoxia. It is our hypothesis that DNA damage produced under hypoxia is more complex and less likely to be repaired. This type of damage is especially problematic for NHEJ deficient xrs6 cells. Taken together, DNA damage due to direct action of X-rays was more akin to those by high LET radiations.10th International Workshop Radiation Damage to DN

OH Radicals from the Indirect Actions of X-Rays Induce Cell Lethality and Mediate the Majority of the Oxygen Enhancement Effect

We examined OH radical-mediated indirect actions from Xirradiation on cell killing in wild-type Chinese hamster ovarycell lines (CHO and AA8) under oxic and hypoxic conditions,and compared the contribution of direct and indirect actionsunder both conditions. The contribution of indirect action oncell killing can be estimated from the maximum degree ofprotection by dimethylsulfoxide, which suppresses indirectaction by quenching OH radicals without affecting the directaction of X rays on cell killing. The contributions of indirectaction on cell killing of CHO cells were 76% and 50% underoxic and hypoxic conditions, respectively, and those for AA8cells were 85% and 47%, respectively. Therefore, the indirectaction on cell killing was enhanced by oxygen during Xirradiation in both cell lines tested. Oxygen enhancementratios (OERs) at the 10% survival level (D10 or LD90) for CHOand AA8 cells were 2.68 6 0.15 and 2.76 6 0.08, respectively.OERs were evaluated separately for indirect and directactions, which gave the values of 3.75 and 2.01 for CHO, and4.11 and 1.32 for AA8 cells, respectively. Thus the generallyaccepted OER value of 3 is best understood as the averageof the OER values for both indirect and direct actions. Theseresults imply that both indirect and direct actions on cellkilling require oxygen for the majority of lethal DNAdamage, however, oxygen plays a larger role in indirect thanfor direct effects. Conversely, the lethal damage induced bythe direct action of X rays are less affected by oxygenconcentration