Macrophage-Mediated Antitumor Activity Induced by Poly(Itaconic Acid-co-Styrene

Abstract

The injection of OK-432 led to an increase in both the number of PEC and the percent of macrophage in the PEC. The injection of poly(itaconic acid-co- styrene) (PIS) led to no increase in either the number of PEC or the percent of macrophage in the PEC compared to an injection of saline. Both PIS and OK- 432 induced a high level of cytostatic activity against MCA tumor cells. The combination of PIS and OK-432 resulted in a marked increase in PEC number and the percent of macrophages, as well as induced a high level of macrophage- mediated cytostatic activity. Although repeated injections of PIS alone into mice bearing MCA or LLC tumor cells showed no significant increase in median survival time, repeated injections of PIS together with OK-432 led to an increase in median survival time. The results showed that PIS and OK-432 enhanced synergically to induce in vivo antitumor activity in tumor bearing mice.