The Use of Ferritin-conjugated Antibodies in Electron Microscopic Studies of Influenza and Vaccinia Viruses

Electron microscopic examination of thin sections through infected cells has resulted in the accumulation of considerable information not only about viral structure and development but also regarding associated alterations in host cell architecture (Rose and Morgan, 1960). Unfortunately, however, most of these studies apply of necessity to terminal stages in the formation of the virus, since it has rarely been possible to distinguish viral components before their assembly into recognizable particles. In order to identify viral constituents which are either in process of synthesis or have accumulated during the course of infection it is necessary to label them in some manner. One method of accomplishing this is to utilize specific antibody conjugated with ferritin (Singer, 1959). Ferritin consists of protein (mol. wt. c. 750,000) enclosing an iron core which is about 55 Å in diameter and readily visible in the electron microscope. The procedure of conjugation employing m-xylelene diisocyanate has...