Increase in Haptoglobin and Haptoglobin-Hemoglobin Complex in Mouse Serum after Administration of an Antitumor Agent, LC 9018

Changes of protein components (LA, LB, LC, and X) in mouse serum after administration of an antitumor agent, LC 9018 (lyophilized preparation of Lactobacillus casei, YIT 9018), were investigated. The intraperitoneal injection of LC 9018 caused an increase in these proteins one or two days after administration. The LC component was purified from mouse serum and was identified as haptoglobin. In addition, LA was identified as an intermediate of a haptoglobin-hemoglobin complex [Hp-Hb(α1β1)] and X as a haptoglobin-hemoglobin complex [Hp-Hb(α2β2)] because addition of increasing amount of hemoglobin to purified haptoglobin formed X via LA and all of these components were immunoprecipitated with anti-haptoglobin IgG.