The toxicity of human serum against Ehrlich cells--an attempt at characterizing responsible components

A biochemical characterization of the toxic action of human serum on murine Ehrlich ascites tumor cells was attempted. Some observations are consistent, other inconsistent, with the hypothesis of complement dependent antibodies reacting with ubiquitous antigens on these cells. Studies using various serum fractions, and with pure preparations of human serum proteins, have not given consistent results. Of particular interest is the puzzling observation that the toxic action of human serum fractions sometimes only appears some time after the fractionation.