Growth of Mouse Ascites Tumor Cells in Diffusion Chambers. II. Lysis and Growth Inhibition by Diffusible Isoantibody

Abstract

Isoantibody was injected into mice in which the DBA/2 lymphoma was growing rapidly inside sampling-type diffusion chambers. Many of the tumor cells were lysed within 4 hours, some recovery was evident by 24 hours, and the cell count inside the chamber increased rapidly within 48 hours. Lysis was roughly proportional to the amount of serum injected. Recovery of the tumor-cell population could be delayed, apparently indefinitely, by repeated injections of antiserum. Lysis or growth inhibition could be shown for several other ascites tumors including an Ehrlich clone and MC1M sarcoma. Two lymphomas, although lysed at high serum doses, appeared to have an accelerated rate of growth after injection of small volumes of antibody. When this acceleration was studied in greater detail, it was found that the rise in cell count followed a slight initial fall. Reasons for the failure of antibody to lyse all the tumor cells are not fully understood since the population may be completely destroyed in tests in vitro; the availability of complement appears to be a limiting factor.