Elution of tumor-directed antibody from kidneys of mammary tumor-bearing mice.

Immunoglobulin-containing eluates, prepared from kidneys of Paris RIII mammary tumor-bearing mice approximately 10 months old, were incubated with frozen sections of mouse mammary tumor and normal lactating mammary gland and examined by immunofluorescence. The eluates diffusely strained the tumor but did not stain the nonneoplastic lactating mammary gland. Mammary tumor and normal lactating mammary gland were both stained by an antiserum to mammary tumor virus (MuMTV). The euglobulin portion of the eluates, when fractionated on a Sephadex G-200 column, yielded an IgG fraction which was shown by immunodiffusion to react with Paris RIII mammary tumor extract and with anti-mouse globulin but not with nonneoplastic mouse tissue extracts. Since the lactating mammary glands of these animals contain MuMTV, the antibody-containing fraction eluted from the kidneys appeared to be tumor directed rather than virus directed.