Implications for Immunotherapy of Acute

Radiation Syndromes. Part 2.Dmitri Popov, MD (Russia), Ph.D. Radiobiology.

Advanced Medical Technology and Systems Inc. Richmond Hill, Canada.

Immunotherapy of Acute Radiation Syndromes.• Research Proposal:

Implications for Immunotherapy of Acute Radiation Syndromes. Part 2.• Dmitri Popov• Full-text available · Research Proposal · Feb 2017• File name: Implications for Immunotherapy of ARS2.pptx

DOI: 10.13140/RG.2.2.15634.66249

Radiation and cell structure damages. • Ionizing radiation and autoimmunity. Induction of autoimmune disease in mice by

high dose fractionated total lymphoid irradiation and its prevention by inoculating normal T cells.• N Sakaguchi, K Miyai and S Sakaguchi• J Immunol March 1, 1994, 152 (5) 2586-2595;• “ irradiation of both the thymus and the peripheral lymphoid organs/tissues was

required for efficient induction of autoimmune disease by TLI. TLI eliminated the majority of mature thymocytes and the peripheral T cells for 1 mo, and inoculation of spleen cell, thymocyte, or bone marrow cell suspensions (prepared from syngeneic nonirradiated mice) within 2 wk after TLI effectively prevented the autoimmune development. Depletion of T cells from the inocula abrogated the preventive activity.”

Radiation and cell structure damage.• Ionizing radiation and autoimmunity. Induction of autoimmune disease in mice by

high dose fractionated total lymphoid irradiation and its prevention by inoculating normal T cells.• N Sakaguchi, K Miyai and S Sakaguchi• J Immunol March 1, 1994, 152 (5) 2586-2595;• “CD4+ T cells mediated the autoimmune prevention but CD8+ T cells did not. CD4+

T cells also appeared to mediate the TLI-induced autoimmune disease because CD4+ T cells from disease-bearing TLI mice adoptively transferred the autoimmune disease to syngeneic naive mice. Taken together, these results indicate that high dose, fractionated ionizing radiation on the lymphoid organs/tissues can cause autoimmune disease by affecting the T cell immune system, rather than the target self-Ags, presumably by altering T cell-dependent control of self-reactive T cells.”

Radiation and autoimmune reactions.• “Autoimmune disease occurs when a specific

adaptive immune response is mounted against self antigens. The normal consequence of an adaptive immune response against a foreign antigen is the clearance of the antigen from the body. Radiation damaged cell,virus-infected cells, for example, are destroyed by cytotoxic T cells, whereas soluble antigens( which could be a product of apoptosis or necrosis of irradiated cells) are cleared by formation of immune complexes of antibody and antigen, which are taken up by cells of the mononuclear phagocytic system such as macrophages”

Immunobiology: The immune system in Health and Disease. Janeway C. et al. New Yourk. 2001.

Autoimmune reactions.• Autoimmune reactions could be induced against normal self antigens,

or against self antigens which is damaged or modified after irradiation, chemical modification, chemical reactions, modified by viruses or bacteria, damaged by free radicals.• Radiation disrupt immunological tolerance. Normally immune system

distinguish body normal proteins and proteins damaged by viruses, bacteria or chemicals. • Several processes make immunological recognition for self antigens

difficult. For example, radiation damage DNA and induce genes mutation.

Protein damage by radiation.• Trends Biochem Sci. 2005 Apr;30(4):213-9.• When X-rays modify the protein structure: radiation damage at

work.• Carugo O1, Djinović Carugo K.• Proceeding of the National Academy of Science of the United States

of America.• Specific chemical and structural damage to proteins produced by

synchrotron radiation. • Martin Weik*†, et al

Genetic mutation after irradiation• Radiation induce genetic mutations of DNA that code for the MHC

membrane proteins may lead to autoimmune reactions.• Irradiated cells displayed damaged proteins which are resembled

normal proteins on the major histocompatibility complex on outer surface of cell membrane. • When the pathologic irradiated antigens induce immunological

response with antibody production, T helper cell activation and activation of cytotoxic T cells.

Radiation damage. • Radiation damage to biological systems is determined by the type of

radiation, the total dosage of exposure, the dose rate, and the region of the body exposed. Three modes of cell death—necrosis, apoptosis, and autophagy—as well as accelerated senescence have been demonstrated to occur in vitro and in vivo in response to radiation in cancer cells as well as in normal cells.• Mechanisms of Radiation Toxicity in Transformed and Non-Transformed Cells

Ronald-Allan M. Panganiban, Andrew L. Snow and Regina M. Day * Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA; E-Mails: ronald-allan.panganiban@usuhs.edu (R.-A.M.P.); andrew.snow@usuhs.edu (A.L.S.)

Radiation damage.• Ionizing radiation (IR) generates both direct and indirect damage to

biological molecules. In high linear energy transfer (LET) radiation, such as neutrons and alpha particles, most of the cellular damage results from the direct ionization of cellular macromolecules including DNA, RNA, lipids, and proteins. • Mechanisms of Radiation Toxicity in Transformed and Non-Transformed

Cells Ronald-Allan M. Panganiban, Andrew L. Snow and Regina M. Day * Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA; E-Mails: ronald-allan.panganiban@usuhs.edu (R.-A.M.P.); andrew.snow@usuhs.edu (A.L.S.)

Radiation damage.• In contrast, low LET radiation, such as X-rays and gamma rays, indirect

damage to biological macromolecules occurs following the generation of reactive oxygen species (ROS). ROS, especially superoxide and hydroxide radicals from the radiolysis of intracellular H2O, can have many effects, including the oxidation of biological macromolecules and activation of intracellular signaling pathways.• Mechanisms of Radiation Toxicity in Transformed and Non-Transformed Cells

Ronald-Allan M. Panganiban, Andrew L. Snow and Regina M. Day * Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA; E-Mails: ronald-allan.panganiban@usuhs.edu (R.-A.M.P.); andrew.snow@usuhs.edu (A.L.S.)

Radiation damage.

Radiation induced autoimmune processes.• Antibodies to self-antigens, proteins which is not normal, but

damaged by radiation, presented by MHC complex. Auto-antigens modified by radiation induce activation of plasma cells and elaboration antibodies to radiation modified self-antigens.

Radiation and Antigen Presenting Cells. • Antigen-presenting cells (APCs) are a heterogeneous group of

immune cells that mediate the cellular immune response by processing and presenting antigens for recognition by certain lymphocytes such as T cells. • Classical APCs include dendritic cells, macrophages, Langerhans cells

and B cells.

MCH class 1.• “MHC class I molecules are one of two primary classes of

major histocompatibility complex (MHC) molecules (the other being MHC class II) and are found on the cell surface of all nucleated cells in the bodies of jawed vertebrates. They also occur on platelets, but not on red blood cells. Their function is to display peptide fragments of non-self proteins from within the cell to cytotoxic T cells; this will trigger an immediate response from the immune system against a particular non-self antigen displayed with the help of an MHC class I protein. Because MHC class I molecules present peptides derived from cytosolic proteins, the pathway of MHC class I presentation is often called cytosolic or endogenous pathway”

MCH class 1 and Radiation.• J Exp Med. 2006 May 15; 203(5): 1259–1271.• doi: 10.1084/jem.20052494. Radiation modulates the peptide

repertoire, enhances MHC class I expression, and induces successful antitumor immunotherapy. Eric A. Reits, et al.• The effect of irradiation on antigen presentation by MHC class I

molecules was studied. Cell surface expression of MHC class I molecules was increased for many days in a radiation dose-dependent manner as a consequence of three responses.

MHC class 1.• “Initially, enhanced degradation of existing proteins occurred which

resulted in an increased intracellular peptide pool. Subsequently, enhanced translation due to activation of the mammalian target of rapamycin pathway resulted in increased peptide production, antigen presentation, as well as cytotoxic T lymphocyte recognition of irradiated cells. In addition, novel proteins were made in response to γ-irradiation, resulting in new peptides presented by MHC class I molecules, which were recognized by cytotoxic T cells.”

MHC class 1.• “The best-known effect of ionizing radiation is the induction of

double-stranded DNA breaks, which can result in mutations leading to transformation and tumor formation if DNA repair fails.” • “Cells respond to DNA damage by activating complex pathways to

arrest the cell cycle, allowing DNA repair, or inducing programmed cell death”

Major Histocompatibility Complex class 1.• “Microarray analysis of cells after ionizing radiation has revealed up-

regulation of nucleotide excision repair genes, cell cycle genes, and genes involved in apoptosis . In addition, irradiation-induced radical formation modifies proteins by radical-induced cross-linking, breakage of disulphide bonds, and amino acid side-chain oxidation , which may result in protein unfolding and degradation.”• “Absorption of radiation can occur directly within proteins but mostly

causes radiolysis of water, which constitutes up to 90% of the volume of cells. The resulting short-living radicals can modify intracellular proteins and DNA.”

Major Histocompatibility Complex Class 1.• “It is unknown if γ-irradiation modifies the intracellular protein pool in

vivo and whether the resulting MHC class I peptide repertoire is altered by this treatment. We show that γ-irradiation enhanced peptide production and surface expression of MHC class I for many days at higher doses.” • “In addition, the MHC class I peptide repertoire now includes

radiation-specific peptides. The radiation-induced effects on MHC class I antigen presentation may have important consequences because combining radiotherapy with immunotherapy results in superior antitumor responses.”

MCH class 2.• “MHC class II molecules are a class of major histocompatibility complex (MHC)

molecules normally found only on antigen-presenting cells such as dendritic cells, mononuclear phagocytes, some endothelial cells, thymic epithelial cells, and B cells. These cells are important in initiating immune responses.• The antigens presented by class II peptides are derived from extracellular proteins

– degraded irradiated cells (not cytosolic as in MHC class I).• Loading of a MHC class II molecule occurs by phagocytosis; extracellular proteins

are endocytosed, digested in lysosomes, and the resulting epitopic peptide fragments are loaded onto MHC class II molecules prior to their migration to the cell surface.• In humans, the HLAs corresponding to MHC class II are HLA-DP, HLA-DM, HLA-DOA

, HLA-DOB, HLA-DQ, and HLA-DR.”

Major histocompatibility complex (MHC) class II.• “Major histocompatibility complex (MHC) class II molecules are cell-

surface glycoproteins that play a central role in the immune system by presenting peptides to the antigen receptor of CD4+ T cells.1 Antigen presentation is not only crucial for the regulation of protective immune responses against invading pathogens, but is also necessary for the maintenance of self-tolerance. Indeed, MHC class II expression directs positive and negative selection processes that shape the specificity of the T-cell-receptor repertoire of the CD4+ T-cell population during its development in the thymus”

Antigen presenting cells and MCH.• “An antigen-presenting cell (APC) or accessory cell is a cell that

displays antigen complexed with major histocompatibility complexes (MHCs) on their surfaces; this process is known as antigen presentation. • T cells may recognize these complexes using their T cell receptors

(TCRs). These cells process antigens and present them to T-cells.”

Radiation and antigen presenting cells.• Dendritic cells(DCs),as professional antigen-presenting cells, are

members of the innate immune system and function as key players during the induction phase of adaptive immune-responses. Uptake, processing, and presentation of antigens direct the outcome toward either tolerance or immunity. • Those cell that express MHC class II molecules along with co-

stimulatory molecules and pattern recognition receptors are often called professional antigen-presenting cells.

Radiation and antigen presenting cells.• An antigen-presenting cell (APC) is a cell that displays radiation

antigens complexed with major histocompatibility complex (MHCs) on their surfaces; this unique process is known as antigen presentation.• Antigen-presenting cells process antigens and present them to T-cells.