Dissociation between lymph node and peripheral reactivity in immunological unresponsiveness to DNCB

Contact sensitivity and production of anti-DNP-antibodies induced by epicutaneously applied dinitrochlorobenzene (DNCB) can be permanently suppressed by a previous intravenous injection of a high dose of dinitrobenzene-sulphonate (DNBSO₃). The animals fail to develop a paracortical area rich in pyroninophilic cells, in lymph nodes regional to the local application of hapten, characteristic of sensitized controls.

Following the injection of lymphoid cells from normal syngeneic donors into these unresponsive animals, large pyroninophilic cells develop in the paracortical area 4 days after sensitization and in some cases antibody production is restored. However, contact sensitivity remains suppressed.

If a high dose of DNBSO₃ (600 mg/kg) is injected intravenously on the same day as DNCB is applied locally, or when a low dose of DNBSO₃ (60 mg/kg) is administered 12 weeks before DNCB, contact sensitivity and production of anti-DNP-antibodies are also suppressed but in such animals the development of a paracortical area containing large pyroninophilic cells is not inhibited.

In both cases an immune reaction can be suppressed in the presence of a paracortical area containing large pyroninophilic cells. Therefore it appears that this state of unresponsiveness is not exclusively conditioned by the absence of large pyroninophilic cells in paracortical areas and may be associated with other factors.