The nature and some biological properties of the natural antitumor cytotoxins previously found in normal C3Hf serum, were investigated. By immunoelectronmicroscopy study, employing rabbit hybrid antibodies with specificity for mouse Ig and ferritin, the C3Hf cytotoxins were shown to belong to immunoglobulins. By gel filtration, by inhibition experiments of the cytotoxic serum activity with monospecific anti-IgG and anti-IgM sera, and by 2-mercaptoethanol treatment of the C3Hf serum, the cytotoxic immunoglobulins were demonstrated to belong to the IgM class. They were not inactivated by heating until 60°C and were able to activate guinea pig, rabbit, and human complement. The highest cytotoxic activity of the normal C3Hf serum was found when cells and serum were incubated at low temperature, suggesting a low binding affinity of the cytotoxic IgM.
|Number of pages||12|
|Publication status||Published - 1976|
ASJC Scopus subject areas
- Cancer Research