Antibody mediated suppression of tumor growth. I. Suppression by murine IgG1 isolated from alloantiserum

The tumor suppressive activity of murine IgG1 antibody was studied in vivo. IgG1 was isolated from hyperimmune alloantisera against a murine lymphoma, 6C3HED, by absorption with heat killed, formalinized Staphylococcus aureus. Cowan strain I, followed by DEAE ion exchange chromatography and Sephadex G 200 gel filtration chromatography. The isolated IgG1, which had no detectable IgM, IgA, IgG2a, IgG2b or IgG3, could suppress the growth of the tumor. In addition, DEAE and Sephadex G 200 column profiles of the in vivo tumor suppressive activity showed good correlation with the profiles of total IgG1 immunoglobulin and anti tumor antibody assayed for IgG1 heavy chains and kappa light chains. The IgG1 tumor suppressive activity was not diminished after heating at 56°C for 30 min.