Abstract
HEAE cannot be induced in either guinea pigs using 1010 or 20x1010 organisms of B. pertussis or in rabbits using 4x1010 organisms of B. pertussis and basic protein from the following species: guinea pig, Lewis rat, human, bovine, porcine, monkey and rabbit. The only encephalitogenic region for Lewis rats which also produces HEAE in Lewis rats is not encephalitogenic in either rabbits or guinea pigs. Therefore it seems highly probable that there is only one HEAE determinant for all species which are able to express HEAE.