Human peripheral lymphocytes and cancer. In vitro studies on the basic protein, histone F2A1 fraction.

The interaction of the highly purified basic protein "antigen", calf thymus histone F2A1 fraction, with peripheral lymphocytes isolated from patients with cancer and from normal subjects has been studied. Analysis, by SDS polyacrylamide gel electrophoresis of the basic protein remaining in the supernatant fluid after interaction with low concentrations of lymphocytes from patients showed the presence of a component(s) of molecular weight smaller than the original histone F2A1 fraction. Similar experiments using lymphocytes derived from normal subjects indicated that this component(s) is absent, or at least is present in only small amounts. This difference could be partially abolished by using high concentrations of cell preparations. It is suggested that the observed difference is due at least in part, to differences in protease activity between the two preparations. The possible significance of these findings in relation to the macrophage electrophoretic mobility test for cancer is discussed.