[National Institute of Biomedical Innovation, Health and Nutrition] Importance of mineral oil in experimental autoimmune disease development models
*National Institute of Biomedical Innovation, Health and Nutrition* Press release: September 17, 2024
**
Importance of mineral oil in experimental autoimmune disease development models *Constituent tridecylcyclohexane is involved in experimental autoimmune disease induction*
National Institute of Biomedical Innovation, Health and Nutrition (Ibaraki City, Osaka Prefecture, Chairman: Yusuke Nakamura)
Sub-project leader Norifumi Iijima of the Biofunction Molecular Control Project and others are working at the National Hospital Organization Hokkaido Medical Center and the National University Corporation Tokyo. In collaboration with the University Institute of Medical Science, we discovered that tridecylcyclohexane contained in mineral oil has a significant effect on the induction of autoimmune diseases in laboratory animals.
Autoimmune diseases are a general term for diseases in which, for some reason, immune cells react to their own cells and tissues, causing cell death and tissue damage. Although various triggers based on human lifestyle have been cited, the causes of autoimmune diseases remain unclear. On the other hand, autologous antigen and killed
Mycobacterium tuberculosis 1 were mixed with incomplete Freund’s adjuvant 2.
(Incomplete Freund’s adjuvant:
By inoculating experimental animals in combination with IFA), it is possible to induce pathological conditions such as autoimmune diseases in experimental animals.
(Key points of results)
–
In an autoimmune disease model induced by inoculating experimental animals with self-antigens killed Mycobacterium tuberculosis bacteria IFA, we confirmed that autoimmune diseases did not develop simply by inoculating experimental animals with self-antigens killed Mycobacterium tuberculosis bacteria. Ta.
– If mineral oil, a component of IFA, is inoculated with
autoantigens and killed Mycobacterium tuberculosis bacteria, autoimmune diseases may occur.
(at least autoimmune encephalomyelitis and collagen-induced arthritis) were found to be induced.
–
We discovered that autoimmune disease was most strongly induced when experimental animals were inoculated with tridecylcyclohexane, which is contained in mineral oil, along with autoantigens and killed Mycobacterium tuberculosis bacteria.
It is hoped that elucidating the mechanism of autoimmune disease induction using tridecylcyclohexane will lead to the development of new therapeutic drugs for autoimmune diseases.
The results of this research were published online in the “European Journal of Immunology” on July 18, 2024.
Website: https://onlinelibrary.wiley.com/doi/10.1002/eji.202350957
Previous research has shown that various factors such as gender, genetics, obesity, smoking, and infectious diseases can induce autoimmune diseases, but the causative factors have not been identified.
On the other hand, in the early 1900s, complete Freund’s adjuvant [killed Mycobacterium tuberculosis incomplete Freund’s adjuvant] (IFA)] was developed, and many researchers have continued to improve the experimental conditions that induce the development of autoimmune diseases in laboratory animals. As a result, it has become possible to induce various autoimmune diseases by inoculating experimental animals with self-expressed antigens in combination with two types of adjuvants: killed Mycobacterium tuberculosis and IFA. Therefore, we focused on the fact that it is possible to induce the desired type of autoimmune disease by changing only the self-antigen.
Contents of this research
In this study, we demonstrated that killed Mycobacterium tuberculosis bacteria and self-antigens alone did not induce autoimmune diseases, and that IFA
It was discovered that the symptoms of an autoimmune disease were induced by vaccination with the same drug. IFA is mainly composed of mineral oil and the surfactant mannide monooleate. Therefore, this time, we selected MOG (myelin oligodendrocyte glycoprotein) as an autoantigen and investigated the components of IFA that are involved in autoimmune disease induction.
First, when mice were inoculated with MOG killed Mycobacterium tuberculosis bacteria mineral oil, it was revealed that autoimmune encephalomyelitis developed. On the other hand, inoculating mice with MOG killed Mycobacterium tuberculosis mannide monooleate did not induce encephalomyelitis. The above results indicate that only inoculation of mineral oil together with MOG and killed Mycobacterium tuberculosis is effective in inducing autoimmune diseases.
Analysis of mineral oil revealed that it contains at least 12 hydrocarbons in varying proportions (Figure 1A). MOG contains the same amount of hydrocarbons as in mineral oil.
When mice were inoculated with M. tuberculosis and killed
Mycobacterium tuberculosis bacteria, MOG using tridecylcyclohexane Autoimmune encephalomyelitis was strongly induced only when inoculated with killed Mycobacterium tuberculosis bacteria (Figure 1B). From the above results, it is clear that tridecylcyclohexane, which is contained in trace amounts in mineral oil, is
It was revealed that mice had the highest ability to develop autoimmune diseases when inoculated with killed Mycobacterium tuberculosis bacteria. IFA
It was previously thought that IFA was effective by encapsulating the antigen in a water-in-oil emulsion and releasing it slowly.
Since it is not possible to make an emulsion of an aqueous solution (containing the antigen) of more than 100 times the volume of tridecylcyclohexane (0.9%), it is unlikely that the antigen can be encapsulated. This suggests that the mechanism may be different from what was previously thought.
Figure 1. Autoimmune disease induction when autoantigens and killed Mycobacterium tuberculosis are inoculated with the same amount of hydrocarbons as contained in mineral oil.
A Percentage of hydrocarbon groups contained in mineral oil
B autoantigen (MOG) and killed Mycobacterium tuberculosis bacteria in 2,6,10,14-tetramethylhexadecane (0.5%), tridecylcyclohexane (0.9%) or Scores indicating clinical symptoms after inoculation of C67BL/6 mice with hexadecane (0.01%)
ripple effect
The presence of mineral oil or its constituent tridecylcyclohexane can induce autoimmune diseases in laboratory animals when infected with pathogenic microorganisms or when tissues are destroyed due to strong inflammation and self-antigens are exposed. This study suggests that there is a In the future, it is expected that tridecylcyclohexane will be used as a clue to elucidate the mechanism of autoimmune disease induction, and that this will lead to the development of new therapeutic drugs for autoimmune diseases.
Research support
The results of this research are based on the research topic “T “Elucidation of neural activity control mechanisms by cells”, research project of the Japan Agency for Medical Research and Development (AMED) Infectious Disease Research Innovation Initiative (J-PRIDE) project “Tissue-localized memory”
“Elucidation of the reactivation mechanism of latent infection viruses focusing on T cells” and Taiki Life Welfare Foundation
Focusing on the research theme of the 53rd Medical Research Grant, “Elucidation of the differentiation induction mechanism and function of autoreactive activated T cells that cause neurodegenerative diseases”
Japan Agency for Medical Research and Development (AMED) Vaccine/New Modality Research and Development Project, Uehara Memorial Life Science Foundation, Takeda Science Foundation, Mochida Memorial Foundation for Pharmaceutical Sciences, Naito Memorial Science Foundation, Daiichi Sankyo Life Science This research was carried out with support from the Research Foundation, the Astellas Metabolic Research Group, and the Novartis Foundation for the Promotion of Science.
Paper information
Paper title: Tridecylcyclohexane in incomplete Freund’s adjuvant is a critical component in inducing experimental autoimmune diseases
Author: Norifumi Iijima1*§,, Tomoya Hayashi2, Masaaki Niino3, Yoichi Miyamoto1, Masahiro Oka4 and Ken J Ishii2* (*Corresponding author, §,
Representative contact information)
1. National Institute of Biomedical Innovation, Health and Nutrition, Drug Discovery Design Research Center, Biofunction Molecular Control Project
2. Department of Vaccine Science, Institute of Medical Science, University of Tokyo
3. Department of Clinical Research, Department of Neurology, National Hospital Organization Hokkaido Medical Center
4. National University Corporation Osaka University Research Institute for Microbial Diseases
Magazine: European Journal of Immunology
Glossary
1. Killed Mycobacterium tuberculosis:
A heat-sterilized preparation of Mycobacterium tuberculosis H37Ra strain. Cell wall glycolipids TDM, lipoproteins, and lipomannan expressed in Mycobacterium tuberculosis are expressed in
antigen-presenting cells.
It is recognized by the lectin receptors Mincle and TLR2, and induces the activation of transcription factors involved in inflammation.
2. Adjuvant:
Adjuvants are substances used with vaccines to enhance the induction of the desired immune response. Common attenuated live vaccines and inactivated vaccines contain pathogen components and nucleic acids that activate immune responses, so they can induce strong immune responses without the addition of adjuvants. be. Vaccinations using pathogen-derived proteins or peptides require an adjuvant to induce a strong immune response.
Incomplete Freund’s adjuvant is a mixture of mineral oil and the surfactant mannide monooleate, and the combination of killed Mycobacterium tuberculosis and incomplete Freund’s adjuvant is called complete Freund’s adjuvant. Different experimental autoimmune diseases can be induced by adding autoantigens such as myelin antigen, type 2 collagen, or retinal S antigen to complete Freund’s adjuvant and inoculating them into experimental animals.
About the Institute of Medical Infrastructure, Health and Nutrition It was established on April 1, 2015 by the merger of the National Institute of Biomedical Innovation and the National Institute of Health and Nutrition. This research institute is characterized by a wide range of research from medical to health science, and aims to maximize the results of research and development in order to contribute to the sound development of the national economy and other public interests through improving the level of science and technology in Japan. It is positioned as a national research and development agency whose purpose is to secure
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