EAE Induction by Active Immunization in Lewis Rats

Recommended protocol for use with:

This kit is recommended for study of experimental autoimmune encephalomyelitis (EAE), including testing efficacy of potential therapeutics. It will induce EAE in Lewis rats by active immunization with antigen in an emulsion with complete Freund's adjuvant (CFA).

Each kit supplies enough material for 10 rats.

EAE onset for most rats occurs 10 to 12 days after immunization, with peak of disease usually 3 days after onset for each rat. The peak generally lasts 1 to 3 days. All rats will fully recover by Day 20 after immunization, without relapses.

Rats are typically observed for 3 weeks.

Rat selection and handling

For the most uniform EAE development, use female Lewis rats at age 10 to 14 weeks. All rats should be the same age. Male rats can be used and will develop slightly milder EAE.

We have observed significant differences in EAE development in rats obtained from different breeders; this can change over time. As of this writing (see version date at the end of this protocol), in the United States we recommend Lewis rats from Charles River Laboratories.

Successful induction of EAE requires low-stress rat handling and husbandry procedures, good injection technique, use of appropriate rats, and good quality, stable, antigen emulsion. Stress decreases EAE susceptibility; minimizing rat stress is very important for successful EAE induction.

For consistent EAE, minimize rat stress as follows:

Administration of antigen emulsion

Emulsion should be administered subcutaneously, at two sites, 0.1 mL/site (0.2 mL/rat total).

Good subcutaneous injection technique is important for successful EAE induction, both for proper emulsion administration and also to minimize animal stress. Because EAE susceptibility is influenced by stress, the same person should dose all groups in an experiment (because different people may inflict different amounts of stress).

Lower back injection
  1. Have assistant gently restrain rat against cage.

  2. Inject rat subcutaneously on one side of lower back with 0.1 mL of emulsion (Figure 1).

    Keep the needle inserted into the subcutaneous space for 10 to 15 seconds to avoid leakage of the emulsion. Alternatively, a light pull on the syringe plunger will prevent leakage.

  3. Inject rat subcutaneously on the other side of lower back with 0.1 mL of emulsion.

    Again, keep the needle inserted into the subcutaneous space for 10 to 15 seconds or lightly pull on the syringe to avoid leakage.

    Repeat (1-3) for all rats.

References

[1] McFarlin DE, Blank SE, Kibler RF, J. Immunol. 1 13:712 (1974)
[2] Kardys E and Hashim GA, J Immunol 127:862 (1981)
[3] Mannie MD, Paterson PY, U'Prichard DC, Flouret G., Proc Natl Acad Sci USA 82:5515 (1985)
[4] Hashim GA, Day ED, Fredane L, Intintola P, Carvalho E, J Neurosci Res. 16(3):467 (1986)



Appendix A - Rat EAE Scoring Guide

Version: 2023-06-04