An enzyme-linked immunoassay for the detection of antibodies to the mouse mammary tumor virus: application to human breast cancer.

Overview

An enzyme-linked immunoassay (ELISA) was developed, using the mouse mammary tumor virus (MMTV) fixed to wells of a microtiter plate, for the determination of antibodies to MMTV. The intensity of the final color change was dependent upon virus or viral antibody concentration. MMTV antibody was readily detectable in sera diluted as much as 1 : 2800. Fixed MMTV bound antibodies to an internal viral protein (p 28) as well as to viral envelope components (gp 52, gp 34), demonstrating that the virus was rendered permeable by our procedure. Applying this assay to human sera, significant differences (P less than 0.005) in IgG binding to MMTV were detected between sera of breast cancer patients, benign breast disease patients and healthy individuals. 26% of breast cancer-derived sera contained MMTV binding antibody; 10% of benign sera or 8% of normal sera were also positive. The reactivity of human IgG with MMTV was blocked by prior incubation of the virus with antisera to gp 34 or, to a lesser extent, with gp 52. The results demonstrate that MMTV antibodies can be quantitated by this simple, rapid and inexpensive procedure.