Edward M. Opton

Size and Structure of Echo, Poliomyelitis, and Measles Viruses determined by Ionizing Radiation and Ultrafiltration.

Abstract Sizes of the irradiation-sensitive infectivity units of poliovirus types I, II, and III, Echo viruses 1 and 7, and measles virus have been determined by means of irradiation with electrons, alpha particles, deuterons; and the whole particle size by ultrafiltration. The diameters for poliovirus and Echo 7 by all methods fell between 24 and 32 mμ. Alpha particle irradiation gave a slightly larger diameter, 36 mμ, for Echo 1, but measurements by other means were in the same range as poliovirus. The diameter of the measles infectivity sensitive unit was about 60 mμ, but ultrafiltration gave a value of 140 mμ for the over-all diameter. The sizes of the complement-fixing antigens of these viruses have been determined by electron irradiation and all fall between 7 and 13 mμ in diameter. The immunizing antigen of poliovirus was destroyed together with the infective unit, indicating that they are of similar size.