Isolation of brain-infiltrating leukocytes

Area of Science:

• Neuroscience
• Immunology
• Virology

Background:

• Studying the central nervous system (CNS) immune response is crucial for understanding neuroinflammatory diseases.
• Current methods for isolating brain-infiltrating leukocytes (BILs) can be complex and time-consuming.
• Theiler's murine encephalomyelitis virus (TMEV) infection in mice provides a model for acute viral encephalitis.

Purpose of the Study:

• To develop and validate a streamlined method for preparing brain-infiltrating leukocytes (BILs) from TMEV-infected mice.
• To characterize the early innate immune cell populations within the brain during acute viral infection.
• To facilitate the study of immune cell dynamics in the CNS.

Main Methods:

• Mice were infected with TMEV via intracranial injection under isoflurane anesthesia.
• Brains were harvested, homogenized, and subjected to Percoll gradient centrifugation to remove myelin and debris.
• Leukocytes were purified using Ficoll-Paque Plus density gradient centrifugation and analyzed by flow cytometry.

Main Results:

• The method successfully isolated a leukocyte-enriched population of infiltrating cells from the mouse brain.
• Flow cytometry analysis revealed the presence of innate immune cells at early stages of TMEV infection.
• At 24 hours post-infection, enriched populations of Gr1(+), CD11b(+), and F4/80(+) cells were identified in the BILs.

Conclusions:

• This optimized method provides an efficient way to prepare and analyze brain-infiltrating leukocytes (BILs).
• The technique is valuable for characterizing the dynamic immune response to acute CNS infections.
• It enables detailed immunophenotyping of innate immune cells infiltrating the brain during viral encephalitis.