Susceptibility to experimental allergic encephalomyelitis in two strains of rats and their hybrids.

Lewis and PVG strains of rats and their F1-hybrids were challenged with guinea-pig or bovine encephalitogenic protein (EP) in Freund's complete adjuvant (FCA) to produce experimental allergic encephalomyelitis (EAE). The Lewis and F1-rats were also challenged with guinea-pig EP in FCA with a fivefold lower concentration of Mycobacterium butyricum. Data are presented concerning clinical signs and histological changes of EAE showing an intermediate position of susceptibility to EAE for the F1-hybrids compared to the parental strains. The findings are discussed in relation to the mode of inheritance of susceptibility to EAE. Among rats immunized with bovine encephalitogenic protein in FCA a weak activity was registered; this was difficult to evaluate, as it could be an effect of FCA only.