The natural mediator for PMN emigration in inflammation. VIII. Production of leucoegresin-like chemotactic factor in reversed passive Arthus reactions in rats.

The mediation of tissue neutrophilia in the reversed passive Arthus reactions in rats was studied on extract from the skin lesions. Approximately 55 per cent of the neutrophil chemotactic activity in the reactions exhibiting a maximal tissue neutrophilia seemed to be associated with a leucoeresin-like chemotactic factor which can be absorbed by an immunoadsorbent chromatography with anti-rat IgG antibody. On the other hand, the neutrophil chemotactic activity, comparable to most of the remaining chemotactic activity, was reduced in complement-depleted conditions in which the intensity of tissue neutrophilia in the reactions was moderately decreased, suggesting a possible involvement of complement-derived chemotactic factors.