Immunology of the Mouse Mammary Tumor Virus (MTV). Electron Microscopic Studies of Interaction Between MTV and Specific Antibody in Immunodiffusion

Summary

The precipitate line specific for the mouse mammary-tumor virus (MTV), which develops in immunodiffusion plates in which MTV-containing preparations are reacted with specific antisera, contains numerous, characteristic aggregates of type-B virus particles. These aggregates were seen when any of several different MTV-antigen preparations were used in the immunodiffusion assay, including purified sucrose density gradient fractions of infected milk, and when either mouse or rabbit antisera against MTV were used. When rabbit antisera against MTV were labeled either directly with ferritin or indirectly by addition of ferritin-conjugated goat anti-rabbit serum globulin to the immunodiffusion plates, the ferritin granules were localized around the virus particles. These studies provide strong additional evidence that the reactive antigen in the immunodiffusion test for MTV is, in fact, the type-B virus particle, which thus further identifies this virus particle as representing at least one form of MTV.