Site of Virus-like Particles in Rous Fowl Sarcoma Cells

Abstract

A SIMPLE and reliable technique has been evolved for preparing freshly collected ascites tumour cells for electron microscopy¹. It makes use of the fact that when such cells are incubated under appropriate conditions and are brought into contact with ‘Formvar’-coated slides, they change shape within a few minutes of gaining a grip on the ‘Formvar’. The change is from the round form of the free dispersed single cells to a spindle form, and an early stage in the transformation consists of the cells spreading widely and becoming extremely thin. Ascites tumour cells spread thinly in this way are very suitable for electron microscopy; they can be fixed over osmium vapour and transferred easily to electron microscope specimen grids with samples of the ‘Formvar’ to which they adhere².