Antigenic competition in the induction of contact sensitivity in the guinea pig.

The antigen-presenting capability of macrophage modified with a single hapten (dinitrofluorobenzene) is partially or totally abolished by an additional haptenation with a second related (picryl chloride) or unrelated (oxazolone) hapten. This effect, 'antigenic competition', is only partially mediated by suppressor cells. There also seems to be an inhibition of the association of the hapten with particular Ia antigens. The prerequisite for antigenic competition is that both hapten responses are controlled by the same immune response gene. Hapten responses which are controlled by different genes, e.g., dinitrofluorobenzene, picryl chloride, and oxazolone on the one hand and benzilidene acetone on the other, do not compete. The pattern of competition thus varies with the strain of guinea pig.