Autoantigen cross-reactive environmental antigen can trigger multiple sclerosis-like disease

Area of Science:

• Neuroimmunology
• Autoimmune Diseases
• Environmental Health

Background:

• Multiple sclerosis (MS) is an autoimmune disease influenced by genetic and environmental factors.
• The specific environmental triggers for MS remain largely unknown, with infectious agents being a focus.
• T-cell receptor (TCR) ligand prediction algorithms have identified potential cross-reactive peptides from environmental antigens.

Purpose of the Study:

• To investigate if environmental peptide antigens can trigger central nervous system (CNS) disease in a mouse model of MS.
• To test the hypothesis that cross-reactive peptides identified from environmental sources can activate T cells and induce autoimmune disease in vivo.

Main Methods:

• Utilized a transgenic mouse model expressing an MS patient-derived anti-myelin TCR.
• Identified potential cross-reactive environmental peptide sequences using a TCR ligand prediction algorithm.
• Immunized mice with specific environmental peptides (Dictyostelium slime mold and Emiliania huxleyi) to assess disease induction.

Main Results:

• Several myelin epitope cross-reactive epitopes stimulated T cell immunity in the MS model.
• Immunization with a Dictyostelium slime mold peptide, but not Emiliania huxleyi, induced severe, MS-like disease.
• This demonstrates that certain environmental peptides can indeed trigger CNS autoimmune disease in a susceptible host.

Conclusions:

• While these specific environmental epitopes may not be common MS triggers, the findings support the broader 'exposome' concept.
• The study highlights the importance of considering a wide range of environmental exposures, not just the 'infectome,' in understanding MS pathogenesis.
• Future research should explore diverse environmental antigens for their potential role in initiating or exacerbating autoimmune responses in MS.