Studies on the effects of phagocytic stimulation on microbial disease. XII. Action of chaulmoogra oil on the reticuloendothelial system.

In the preceding paper of this series (4) it was reported that application of chaulmoogra oil and certain of its derivatives to the skin surface induced phagocytic activity of endothelial cells of the small skin vessels. The same phenomenon could be induced by histamine, as had previously been observed by Jancso (5) and confirmed by Biozzi et al. (1) and by ourselves (2). We attached a certain importance to this finding, because it revealed some preliminary evidence of the mechanism of action of chaulmoogra derivatives on the host. It appears that under the influence of these substances the endothelial cells undergo a functional metamorphosis. Normally, they have no phagocytic activity, but they may acquire it under the influence of histamine or chaulmoogra derivatives. The influence of either substance, histamine or chaulmoogra derivative, was inhibited by the previous administration of synthetic antihistaminic substances. Jancso also demonstrated that if albino mice or rats were injected with an antihistaminic substance, india ink injected intravenously disappeared from the blood stream of these animals more slowly than was the case with control animals or with histamine-treated animals. We have reported (6) that histamine, and certain substances thought to be histamine liberators, stimulate the reticuloendothelial system (RES) to increased phagocytic activity (3). Once it was seen that the effect of chaulmoogra oil on the endothelial phagocytosis was similar to that of histamine, it became necessary to investigate experimentally whether chaulmoogra oil would similarly stimulate the phagocytic activity of the RES.