How a Typical Virus Triggers Brain Attacks in Multiple Sclerosis

Summary: New research highlights a critical link between antibodies produced against Epstein-Barr virus ( EBV ) and the development of multiple sclerosis ( MS ). Researchers discovered that these popular antibodies falsely target a proteins called GlialCAM in the head, triggering immune responses associated with MS.

The study also revealed how mixtures of genetic risk factors and elevated popular antibody further increase the risk of developing MS. These perspectives may pave the way for improved testing and precise treatment, enhancing our understanding of the genetic and immune interactions underlying this debilitating condition.

Important Information:

    Mistargeted Antibodies: EBV antibodies falsely attack GlialCAM, a mental protein, probably triggering MS.

  • Genetic Links: Certain mixtures of EBV antibody and genetic risk factors significantly elevate MS risk.
  • Possible Diagnostics: Elevated antibodies against GlialCAM and relevant proteins may function as biomarkers for earlier MS recognition.

Origin: Karolinska Institute

In multiple sclerosis ( MS ), antibodies to the common Epstein-Barr virus can accidentally attack a protein in the brain and spinal cord.

New research shows that the mixture of specific viral antigens and genetic risk factors may be linked to a significantly increased risk of MS.

The absence of a protective gene variant ( HLA-A*02: 01 ) in combination with any of the antibodies against proteins in the brain was also associated with a strong increase in risk. Credit: Neuroscience News

The study has been published in the journal&nbsp, PNAS&nbsp, and led by researchers at Karolinska Institutet, Sweden, and Stanford University School of Medicine, USA.

An estimated 90 to 95 percent of adults are carriers of the Epstein-Barr virus ( EBV ) and have formed antibodies against it. Some become sick as kids with few or no symptoms, but in younger adults, the disease can cause gastric fever. After infection, the virus remains in the body in a dormant ( latent ) phase without active virus production.

Attacking a proteins in the mind

People affected by the neurological disease MS, where the immune system problems the brain and spinal cord, is a ship of EBV. However, the methods behind the relationship are not completely understood.

Nowadays, researchers at Karolinska Institutet and Stanford Medicine have confirmed that antibodies to an EBV proteins called EBNA1 may unwittingly respond with a similar protein in the mind called GlialCAM, which probably contributes to the development of MS.

The new study also shows how various combinations of antibodies and genetic risk factors for MS contribute to the danger increase.

” A better knowledge of these methods may eventually lead to better diagnostic equipment and solutions for MS”, says Tomas Olsson, professor of neuroscience at the Department of Clinical Neuroscience, Karolinska Institutet, who led the research that with teacher Ingrid Kockum and associate professor Olivia Thomas.

The researchers examined blood samples from 650 MS individuals and 661 good citizens. They compared the rates of antibody directed against the popular protein EBNA1 and the rates of misguided antibodies against GlialCAM and two other molecules in the head, ANO2 and CRYAB, which are also related to EBNA1.

Increased amounts of antibody

Elevated levels of all these antibodies were detected in people with MS. High antibody levels in combination with a genetic risk factor for MS ( HLA-DRB1*15: 01 ) were associated with a further increase in risk.

The absence of a protective gene variant ( HLA-A*02: 01 ) in combination with any of the antibodies against proteins in the brain was also associated with a strong increase in risk.

” The new findings provide another piece of the puzzle that adds to our understanding of how biological and immune factors interact in MS”, says Lawrence Steinman, professor of neuroscience at Stanford Medicine, who led the analysis there with William Robinson, professor of immunology and rheumatology, and Tobias Lanz, associate professor of immunology and rheumatology.

Biomarker potential

Researchers at Karolinska Institutet now plan to analyse samples collected before MS disease development to see when these antibodies appear.

” If they are already present before the onset of the disease, they may have the potential to be used as biomarkers for early diagnosis”, says Tomas Olsson.

Funding: The research was funded by the Swedish Research Council, the Swedish Brain Foundation, the EU/Horizon Europe, the Knut and Alice Wallenberg Foundation and the Margaretha af Ugglas Foundation, among others.

Tomas Olsson and Lawrence Steinman have received lecture and advisory board fees from several companies.

William Robinson and Tobias Lanz are stockholders and consultants of Ebvio and Flatiron Bio and have filed a patent with Stanford University. See the scientific article for a complete list of conflicts of interest.

About this multiple sclerosis research news

Author: Press Office
Source: Karolinska Institute
Contact: Press Office – Karolinska Institute
Image: The image is credited to Neuroscience News

Original Research: Closed access.
Antibody reactivity against EBNA1 and GlialCAM differentiates multiple sclerosis patients from healthy controls” by Tomas Olsson et al. PNAS


Abstract

Antibody reactivity against EBNA1 and GlialCAM differentiates multiple sclerosis patients from healthy controls

Multiple sclerosis ( MS ) is an autoimmune demyelinating disorder of the central nervous system ( CNS), which is linked to Epstein–Barr virus ( EBV ) infection, preceding the disease. The molecular mechanisms underlying this connection are only partially understood.

We previously described molecular mimicry between the EBV transcription factor EBV nuclear antigen 1 ( EBNA1 ) and three human CNS proteins: anoctamin-2 ( ANO2 ), alpha-B crystallin ( CRYAB), and glial cellular adhesion molecule ( GlialCAM ).

Here, we investigated antibody responses against EBNA1 and GlialCAM in a large cohort of 650 MS patients and 661 matched population controls and compared them to responses against CRYAB and ANO2. We confirmed that elevated IgG responses against EBNA1 and all three CNS-mimic antigens associate with increased MS risk.

Blocking experiments confirmed the presence of cross-reactive antibodies and molecular mimicry between EBNA1 and GlialCAM, and accompanying antibody responses against adjacent peptide regions of GlialCAM suggest epitope spreading.

Antibody responses against EBNA1, GlialCAM, CRYAB, and ANO2 are elevated in MS patients carrying the main risk allele&nbsp, HLA-DRB1*15: 01, &nbsp, and combinations of&nbsp, HLA-DRB1*15: 01&nbsp, with anti-EBNA1 and anti-GlialCAM antibodies increase MS risk significantly and in an additive fashion.

In addition, antibody reactivities against more than one EBNA1 peptide and more than one CNS-mimic increase the MS risk significantly but modestly.

Overall, we show that molecular mimicry between EBNA1 and GlialCAM is likely an important molecular mechanism contributing to MS pathology.

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