Infection of a β-galactosidase-deficient mouse strain with Theiler's murine encephalomyelitis virus reveals limited immunological dysregulations in this lysosomal storage disease

Rouven Wannemacher ^1,2 Felix Stegmann ^3,4 Deborah Eikelberg ¹ Melanie Bühler ¹ Dandan Li ¹ Tim Ebbecke ^3,4 Marie-Kristin Raulf ^3,4 Wolfgang Baumgärtner ^1,2* Bernd Lepenies ^3,4 Ingo Gerhauser ^1,2

• ¹ Department of Pathology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
• ² Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Hannover, Lower Saxony, Germany
• ³ Institute for Immunology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
• ⁴ Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany

A hallmark of many lysosomal storage diseases (LSD) is the alteration of immune responses, often starting before the onset of clinical disease. The present study aimed to investigate how GM1 gangliosidosis impacted the course of an acute central nervous system (CNS) virus infection before the clinical onset of LSD. For this purpose, Glb1 -/-and wildtype control mice (both C57BL/6 background) were intracerebrally infected with the BeAn strain of Theiler's murine encephalomyelitis virus (TMEV) at the age of 5 weeks and sacrificed 4, 7, 14 and 98 days post infection, respectively. Histology, immunohistochemistry, and flow cytometry was used to assess viral load and immune cell activation and infiltration. Both wildtype and Glb1 -/-mice were able to clear the virus from the CNS and did not develop any clinical symptoms of TMEV-associated disease, thus indicating no overt alteration in susceptibility to TMEV infection. However, in the early phase post infection, Glb1 -/-mice displayed a slightly delayed T cell response as well as an increase in the number and activation of CNS microglia. These results suggest that already in the early stage of disease (before clinical onset) GM1 gangliosidosis causes an impaired T cell response and microglial hyperreactivity.