The 'intrinsic adjuvanticity' and immunogenicity of trinitrophenylated lipopolysaccharide.

One thymus-independent immunogen, trinitrophenylated lipopolysaccharide (TNP-LPS) has been studied in vivo and in vitro in C3H/He and C3H/HeJ strains of mice. C3H/HeJ mice have been shown to be low responders, and C3H/He mice high responders to this immunogen. This 'low responder' status of C3H/HeJ mice has been demonstrated to be consequent to an intrinsic defect present at least at the level of B cells. It was demonstrated that high responder cells or 'in vivo milieu' could not restore this deficit to C3H/HeJ cells. It is proposed that the adjuvanticity, mitogenicity and polyclonal activating capacity of LPS are all fundamental to its property of acting as a thymus-independent carrier for the TNP determinant. This observation is discussed from the point of view that the T-cell independence for an antigen cannot derive solely from its multivalency but must depend upon the intrinsic adjuvanticity of that molecule.