Impairment of the Intrinsic Capability of Th1 Polarization in Irradiated Mice: A Close Look at the Imbalanced Th1/Th2 Response after Irradiation

After Bone Marrow Transplantation, the Cell-Intrinsic Th2 Pathway Promotes Recipient T Lymphocyte Survival and Regulates Graft-versus-Host Disease

Recipient T cells can aggravate or regulate lethal and devastating graft-versus-host disease (GVHD) after bone marrow transplantation (BMT). In this context, we have shown before that intestinal immune conditioning with helminths is associated with survival of recipient T cells and Th2 pathway-dependent regulation of GVHD. We investigated the mechanism of survival of recipient T cells and their contribution to GVHD pathogenesis in this helminth infection and BMT model after myeloablative preparation with total body irradiation in mice. Our results indicate that the helminth-induced Th2 pathway directly promotes the survival of recipient T cells after total body irradiation. Th2 cells also directly stimulate recipient T cells to produce TGF-β, which is required to regulate donor T cell-mediated immune attack of GVHD and can thereby contribute to recipient T cell survival after BMT. Moreover, we show that recipient T cells, conditioned to produce Th2 cytokines and TGF-β after helminth infection, are fundamentally necessary for GVHD regulation. Taken together, reprogrammed or immune-conditioned recipient T cells after helminth infection are crucial elements of Th2- and TGF-β-dependent regulation of GVHD after BMT, and their survival is dependent on cell-intrinsic Th2 signaling.

Yiqi Jiedu herbal decoction attenuates the 2 Gy 60Co γ ray induced spleen injury by inhibiting apoptosis and modulating the immune balance

ETHNOPHARMACOLOGICAL RELEVANCE

Irradiation-induced immunosuppression often occurs during radiotherapy in patients, which would increase the risk of opportunistic infections. Many Chinese herbal prescriptions or natural extracts have recently attracted increased radiation protection and therapy attention due to their low toxicity.

AIM OF THE STUDY

The present study aimed to investigate the protective effects of Yiqi Jiedu (YQJD) decoction on spleen injury induced by 2 Gy ⁶⁰Co γ ray in mice.

MATERIALS AND METHODS

A total of 180 Balb/c mice were randomly divided into five groups: blank control (Ctrl), model (IR), positive drug (IRA), low-dose YQJD decoction (IRL), and high-dose YQJD decoction (IRH). After a ten-day intervention, mice were exposed to a single dose of total body irradiation (2 Gy) and sacrificed on the 1^st, 3^rd, and 7^th day after irradiation. The indicators include general observations and body weight, changes in peripheral hemogram, index and histopathology examination of the spleen, distribution of lymphocyte subsets, cytokine levels, and apoptosis in the spleen.

RESULTS

In comparison to the Ctrl group, the body weight, spleen index, peripheral blood cell, and splenocyte quantities decreased significantly after exposure, accompanied by a notable increase of apoptosis in spleen cells. Moreover, ionizing radiation also broke the balance of CD4+/CD8+, Th1/Th2, and Th17/Treg, triggering immune imbalance and immunosuppression. The above injuries occurred on the 1^st day after exposure, worsened on the 3^rd, and were relieved on the 7^th day. However, the pretreatment of YQJD decoction increased the spleen index, improved the spleen structure, and inhibited radiation-induced apoptosis after exposure. Additionally, YQJD decoction has shown its ability to promote immunological balance recovery following exposure by regulating CD4+/CD8+, Th1/Th2, and Th17/Treg ratios, which may minimize the risk of infection. In addition, the high-dose of YQJD decoction showed a better protective effect than the low-dose group.

CONCLUSION

The protective effects of YQJD decoction on 2 Gy ⁶⁰Coγray induced spleen injury were confirmed in this study. This mechanism may be related to inhibiting apoptosis and modulating immune balance. This exploration might provide new insights into the use of Chinese herbs on radioprotection of the immune system.

Effects of Whole Pelvic Radiotherapy on the Distribution of Lymphocyte Subpopulations in Prostate Cancer Patients

INTRODUCTION

In the current study, we have investigated the effects of the different modalities of treatment (volume of radiotherapy [RT], previous surgery) as well as the Gleason score of prostate cancer (PC) on the lymphocyte composition of PC patients undergoing RT.

METHODS

This is a monoinstitutional study that prospectively included PC patients that underwent RT from January 2016 until December 2017. To compare the different evaluations, the Wilcoxon signed-rank test was used among 2 times (Timepoint 0 to Timepoint 1). Percentage variation was calculated for all the lymphocyte subpopulation and was correlated with clinical parameters (previous surgery, Gleason score, and pelvic irradiation) with the χ2 test. The statistical analysis was repeated also on the stratified dataset according to the above parameters (previous surgery, Gleason score, and whole pelvic radiotherapy [WPRT]).

RESULTS

One hundred and eleven patients were included in the present analysis. All the lymphocyte subpopulations resulted significantly lower after RT. The modifications of several lymphocyte subpopulations correlated with previous surgery, Gleason score, and WPRT, although stratified analysis demonstrated that WPRT showed the greatest correlation.

CONCLUSION

Our results could be used to design a prospective trial in order to study the use of WPRT on the lymphocyte subpopulations.

Prolonged Inhalation Exposure to Coal Dust on Irradiated Rats and Consequences

The purposes of this study were to research immune system changes and liver and lung tissues in irradiated rats after prolonged exposure to coal dust. A study was carried out on 30 male Wistar rats that were divided into 3 groups: group I, intact animals; group II, exposure to coal dust and 0.2 Gy γ-irradiation; and group III, combined exposure to 6 Gy γ-irradiation and coal dust. The combination of a low and sublethal dose of γ-irradiation with coal dust leads to a significant change in immunity at the remote period. Particularly, the increase in radioactivity at the combined effect causes weakening of phagocytosis, and reduction in T lymphocytes by a factor of 2, immunoglobulin imbalance, and cytokine dysfunction develop secondary immune failure. During prolonged inhalation with coal dust of irradiated animals with the dose of 0.2 Gy, fibrosis and perivascular sclerosis of the bronchial wall of the lungs are formed, and perivascular fibrosis is formed in the liver. The increase in exposure dose up to 6 Gy in combination with coal, in the distant period, caused pulmonary hypertension amid hypertrophy of light arterial vessels and fibrous changes in arteriole, and destructive changes and collection necrosis develop in liver parenchyma. In the case of dust radiation synergy, the increase in doses leads to a significant immune deficiency, which occurs according to the “dose effect” principle; increases damage to animal tissues; and leads to liver tissue necrosis, pulmonary fibrosis, and pulmonary hypertension.

3,3'-Diindolylmethane Enhances Tumor Regression After Radiation Through Protecting Normal Cells to Modulate Antitumor Immunity

Purpose

Preclinical and clinical data indicate that radiation therapy acts as an immune modifier, having both immune-stimulatory and immunosuppressive effects on the tumor-immune microenvironment (TIME). 3.3’-diindolylmethane (DIM) sensitizes tumor cells to radiation and protects mice from lethal doses of total body irradiation. We hypothesize that protecting nontumoral cells from the adverse effects of radiation treatment (RT) may help to correct immunosuppression resulting from radiation.

Methods and Materials

We generated tumor graft models using immune-competent and immune-deficient mouse strains. Narrow-beamed radiation was targeted to tumor sites using shielding. Tumor regression was monitored after DIM and RT versus RT alone. The effects of DIM on the efficacy of RT were assessed using immunohistochemistry staining and gene expression profiling. Complete blood counts, clonogenic cell survival assays, and global gene expression profiling of cultured cells were performed to study DIM’s radioprotective effects on normal cells.

Results

DIM enhanced tumor regression after RT in immune-competent but not immune-deficient mice. Data indicated that DIM increased intratumoral immune cells after RT, contributing to enhanced immunologic responses such as adhesion and antigen processing. DIM protected normal cells from radiation-induced immediate injuries in vitro and in vivo. Transcriptomic profiling of cultured cells showed that DIM treatment mildly increased expression of some genes that are normally induced after radiation, such as genes involved in cell cycle arrest and apoptosis.

Conclusions

In this study, using cultured cells and preclinical breast cancer models, we show that DIM protects normal cells from radiation-induced immediate cellular injury and combination treatment of DIM and radiation potentiates antitumor immune responses and enhances the efficacy of RT.