Infection of Tumor-Bearing Mice with the Lactic Dehydrogenase Agent

Summary Normal and tumor-bearing mice were experimentally infected with the LDH agent and followed for changes in plasma LDH and GOT activity. 1) Injection of the LDH agent into normal animals produced a 4- to 5-fold increase in plasma LDH activity within 72 hours and a small increase in plasma GOT. 2) Plasma from animals bearing the uninfected plasma-cell tumor SS (70429) showed a gradual increase in both LDH and GOT activity which paralleled the gross increase in tumor size. Transfer experiments failed to reveal a transmissible LDH agent. 3) The tumor-bearing animals which had been infected with the LDH agent showed up to 8 times more plasma LDH activity than the uninfected tumor-bearing animals and up to 88 times more activity than the normal animals. 4) Up to a 22-fold difference in plasma LDH activity was noted between the infected non-tumor-bearing animals and the infected tumor-bearing animals. Serial dilution of plasma from these 2 groups failed to reveal a difference in titer of the LDH agent.