Split unresponsiveness to trinitrophenyl (TNP) determinant. Suppression of anti-TNP antibody responses by sensitization with picryl chloride.

Contact sensitization by epicutaneous application of picryl chloride causes in mice a significant reduction of the antibody responses to immunogenic TNP-conjugates. This split unresponsiveness is along-lasting. It was found that hapten applied on the skin became attached to the serum proteins and the transfer of such a serum into normal recipients, while not influencing the ability of these animals to become contact-sensitized to PCl, rendered them unable to mount the anti-TNP antibody response. Possible mechanisms of split unresponsiveness to the TNP determinant induced by PCl treatment are suggested.