The immunospecificity of altered initial arrest patterns of circulating cancer cells in tumor-bearing mice.

The early arrest patterns of a methylcholanthrene-induced fibrosarcoma were determined after injection of 125IUdR-labelled cells into the systemic circulation of mice bearing transplanted lymphosarcomas, and of normal animals. Similar experiments were performed using radiolabelled lymphosarcoma cells and normal or fibrosarcoma-bearing mice. The results showed that shifts in normal distribution patterns previously observed in tumor-bearing animals injected with cells of the same type as that borne by the animal, were not detectable when cells of a different tumor type were injected. Peritoneal exudate cell migration inhibition assays showed little immunologic cross-reactivity between the two tumors and, together with the results of the distribution studies, indicated that alterations of early arrest patterns in mice sensitized to their tumor is an immunologically specific phenomenon.