Contact sensitivity in the mouse. IX. The role of immunological and non-immunological inflammation in the movement of lymphocytes to immunized lymph nodes.

Normal mice were immunized with picryl chloride. Cr-labelled normal lymph node cells were injected 1–10 days afterwards and the net arrival of radioactivity at the draining lymph nodes estimated. The net arrival at normal unimmunized lymph nodes was 5.3 per cent of the injected dose. This rose to 13.4 per cent 1 day after immunization and then gradually declined. This increased arrival caused by picryl chloride was reduced in mice rendered unresponsive by the repeated injection of picryl sulphonic acid or given a single injection of picryl sulphonic acid 1–6 days before immunization. Blast cells labelled with IUDR from lymph nodes immunized with an unrelated agent also showed an increased arrival at draining lymph nodes. This increased arrival was reduced in unresponsive mice painted with picryl chloride. A single intravenous injection of picryl sulphonic acid increased the arrival of normal lymph node cells at lymph nodes 1 day later and this effect was also diminished in mice rendered unresponsive by repeated injections of picryl sulphonic acid. The arrival of normal lymph node cells at the spleen was reduced by painting with picryl chloride or by a single injection of picryl sulphonic acid given a few days beforehand. Painting the ears of unimmunized mice with picryl chloride increased the arrival of normal lymph node cells and blast cells at the ears. However, the arrival was unaffected by pretreatment with picryl sulphonic acid. It was concluded that the increased arrival of cells in lymph nodes caused by picryl chloride and picryl sulphonic acid had both an immunological and a chemical inflammatory component. In contrast the arrival at painted ears lacked an immunological component. This provided evidence for antibody, or antigen-sensitive cells in apparently unimmunized mice which rapidly release pharmacologically active agents on exposure to antigen.