Sindbis virus infected L cells studied by ferritin-labelled antibodies

Sindbis virus infected L cells were examined by immunoferritin technique at different times after infection. Initially virus-specific antigens appeared diffusely distributed in the cytoplasm and at the surface of vacuoles. Later on, both labelled nucleocapsids surrounding vacuoles and mature virus within their lumen were demonstrated. Maturation of virus occurred predominantly at the periphery of cells, and that mainly by budding from cell processes. The appearance of big crystals consisting of nucleocapsids is a typical event of late stages of infection. These findings are compared with corresponding fluorescent antibody results.