Date of Award
Master of Science (MS)
In each of ten weekly trials, 105 eggs from mated White Leghorn hens were divided into sets of 15 eggs each. Yolks of some of these eggs carried CELO antibodies. Before incubation, the various sets of eggs were inoculated through t he air cell into the albumen with decimal dilutions of the virus, l0-1 through l0-5. In each trial two controls were maintained. One set was inoculated with normal allantoamniotic fluid, the other was not inoculated.
AAF harvested from CELO exposed embryos dying during incubation was found to carry the CELO virus. The higher concentrations of virus adversely affected embryo livability, and only a few receiving the virus diluted l0-1 survived until hatching. Embryos receiving the virus diluted l0-2 or 10-3 were also affected, but to a lesser degree. In the rest of the sets only normal embryo mortality occurred during incubation.
The kidneys were removed from the newly hatched chicks and were used as source tissue for cell cultures. Chicks from each of the seven sets were treated separately. In all cases the cells developed normally, and within 48 to 70 hours a complete sheet was observed. At this time, the star ting medium was replaced with a serum-free maintenance medium. Within 36 to 150 hours of the medium change cytopathogenicity developed in all but the control cells. The speed of development varied inversely with the concentration of the virus used to inoculate the eggs before incubation.
Presence of CELO virus in tissue cultures was confirmed by inoculation of embryonating eggs and three-day-old baby chicks. The development of intranuclear inclusions in chick kidney cell cultures inoculated with the fluids was evident within 48 hours.
Ablashi, Dharam Vir, "Chick Embryo Lethal Orphan Virus (CELO) as a Tissue Culture Contaminant" (1962). Open Access Master's Theses. Paper 811.