Adjuvant-antigen relationships in the production of experimental "allergic" encephalomyelitis in the guinea pig.

Quantitative relationships between the amounts of encephalitogenic neural tissue and mycobacterial adjuvant are presented for the guinea pig, for comparison with similar results obtained in the mouse and presented in an accompanying paper by Lee and Schneider (27). Definite threshold amounts of both neural encephalitogenic and mycobacterial adjuvant can be defined. With the proper amounts of each component, 100 per cent of guinea pigs can be made to develop EAE, 97 per cent dying of it, and over 50 per cent becoming paralyzed by the 12th day after challenge. With moderate amounts of encephalitogen the severity and incidence of EAE can be very great, but this encephalitogenic potential can be masked if large amounts of mycobacteria are employed. The mechanism of this masking effect by excess adjuvant is not known, but speculation centers upon the possibility of competition of antigens of the mycobacteria at the expense of those of the encephalitogen.