A SOLUBLE ANTIGEN OF LYMPHOCYTIC CHORIOMENINGITIS : II. CHARACTERISTICS OF THE ANTIGEN AND ITS USE IN PRECIPITIN REACTIONS.

The soluble antigen of lymphocytic choriomeningitis which is readily separable from the virus is a relatively stable substance and appears to be of a protein nature. A specific precipitin reaction can be demonstrated when immune serum is added to solutions of antigen which have been freed of certain serologically inactive substances. The complement-fixation and precipitation reactions which occur in the presence of immune serum and non-infectious extracts of splenic tissue obtained from guinea pigs moribund with lymphocytic choriomeningitis seem to be manifestations of union of the same soluble antigen and its antibody. On the other hand, the antisoluble substance antibodies and neutralizing substances appear to be different entities.