Viral and Rickettsial Toxins

Electron Microscopy of Hela Cells Infected With Adenoviruses

“…Furthermore, it seems reasonable to assume that nuclei with inclusion bodies and margination of chromatin were sites of viral growth, and such cells were also few in number. Therefore, since light microscopic evidence indicates that practically all of the ceils participate in the cytopathogenic effect, it seems probable that cytopathogenicity due to these viruses is primarily a toxic phenomenon (56) and is related to the agglutination of cells by viruses (57). In this connection, it may be noted that the cytopathogenic effect of influenza virus on HeLa cells is not accompanied by reproduction of the infectious form of the virus (58), and also that cytopathogenicity and viral multiplication can be dissociated in the case of HeLa cells and poliomyelitis virus (59).…”

Growth and Lethal Effects of the Psittacosis Agent in Chicken Embryos of Different Ages

“…In this regard, the age of the embryo at the time of inoculation appeared to have no effect on the average day of death, since at comparable levels of inocula the average day of death in eggs inoculated at 7 and 10 days was nearly identical. Embryos dead on the first day were excluded from the calculations, since these early deaths are thought to be the results of toxin (Cox, 1953), or are nonspecific, probably associated with traumatization by the inoculation procedure since a period of 24 to 48 hr followed without any deaths. The failure to get early deaths after the intravenous inoculation of 7-day embryos is difficult to explain, since one would not expect them to be more resistant to psittacosis toxin or traumatization than the 10-day embryos.…”