| Abstract: | A chemotactic factor (leucoegresin) specific for neutrophilic polymorphonuclear leucocytes was isolated from the site of active Arthus reactions in rabbits. This material was found to be associated with most of the chemotactic activity for the cells in the reactions. Its production by the neutral SH-dependent protease in the reactions was not related to the complement system. The effects of the protease and chemotactic factor were also unrelated to the complement system. Most of the chemotactic activity for PMN leucocytes in active Arthus reactions in rabbits was associated with leucoegresin itself, because the chemotactic activity of inflammatory extracts was significantly absorbed by anti-leucoegresin. Production of this chemotactic substance by the inflammatory SH-dependent protease in the inflamed site was not related to the complement system, because a similar amount of leucoegresin was isolated from the same Arthus skin lesion or from the protease-induced skin lesion in rabbits whose serum complement was apparently depleted by an anti-complementary factor from cobra venom. The in vivo effects of the protease and leucoegresin were not influenced by such depletion of serum complement. It was thus indicated that leucoegresin played a significant and characteristic part in inflammatory leucotaxis. On the other hand, a slight decrease in the PMN emigration in active Arthus reactions in complement-depleted animals suggested the possible presence of a complement-derived chemotactic factor. |
