Antigenic requirements for induction of hyperacute EAE

In rats a hyperacute variant of experimental autoimmune encephalomyelitis (HEAE), distinguisable clinically and histologically from ordinary EAE, is described using whole nervous tissue as immunogen and B. pertussis as adjuvant. Since EAE and HEAE overlap histologically and immunologically, they provide the first experimental evidence distinguishable supporting the concept that certain human demyelinating diseases represent a spectrum of autoallergy. On repeated testing of purified myelin basic proteins (BP's) of six mammalian species (guinea pig, rat, human, ox, rabbit and pig), only guinea pig BP, in combination with Freund's complete adjuvant and B. pertussis, was found capable of inducing HEAE. The mid peptide (residues 45 to 89) was identified as the region of the guinea pig BP molecule inducing HEAE. Comparison of amino acid sequences of this region of BP's from various species allowed further definition of the immunogenic determinant(s) unique to guinea pig BP responsible for HEAE induction. The data suggest that an immunogenic determinant unique to the guinea pig mid peptide is either acting as a secondary encephalitogenic determinant or alternatively as a non encephalitogenic carrier preferentially inducing helper T cells to recruit IgE secreting B cells in response to the encephalitogenic determinant.