Chick embryo lethal orphan (CELO) virus as a possible contaminant of egg-grown virus vaccines

Abstract

SUMMARYThe inactivation kinetics of CELO virus were studied in the presence of 1/4000 formaldehyde. Inactivation of the virus by formaldehyde at 4° C. was not complete after 14 days incubation. Formaldehyde inactivation at 36° C., however, was rapid and no virus was detected after 24 hr. incubation.Neutralizing antibody to CELO virus was detected in 20–88% of sera tested from five flocks of hens. This suggested dissemination of the virus in England and Scotland. However, no CELO virus neutralizing antibody at a serum dilution of 1/8 was detected in 142 normal human sera or in 229 sera from persons who had been immunized with egg grown, inactivated influenza virus vaccine.We would like to thank Professor C. H. Stuart-Harris and Drs J. E. Wilson, D. A. Martin and D. Breeze for their help and their criticisms of the manuscript.Dr G. C. Schild kindly supplied a number of the human sera used in the study. The study was financed in part by the National Fund for Research in Poliomyelitis and other Crippling Diseases and by the British Empire Cancer Campaign.

Avian adenoviruses ‐ a review

“…Although some workers have found that chick embryo liver cells are superior to kidney or lung cells , experience in our diagnostic laboratory has shown little difference; embryo liver cells are now used in this laboratory because these cells are more sensitive to reoviruses (McFerran, 1976, unpublished). Chick embryo fibroblasts and trachéal organ cultures cannot be recommended because they are much less sensitive to adenoviruses than the aforementioned cell cultures (Miller et al, 1972;Oxford and Potter, 1969;Butler et al, 1972). In addition to examining the organ with the lesions, it is advisable to use the intestine and trachea or pharynx for adenovirus isolation, because virus persists in these tissues after it cannot be isolated elsewhere.…”

Replication of celo virus in the chicken chorio‐allantoic membrane

“…Among the many confirmed types of viruses associated with the avian species (Prier, 1966), the chicken embryo lethal orphan (CELO) virus has been investigated in recent years with much interest. The main reason for the rapid accumulation of knowledge concerning the CELO virus appears to be its latency in embryonating chicken eggs, a concomitant relation to vaccine production (Yates and Fry, 1957;Mancini et al, 1969;Oxford and Potter, 1969), and oncogenicity for the hamster (Mancini et al, 1969;Sarma et al, 1965). Sarma et al (1965) first demonstrated that CELO virus inoculated by the subcutaneous route induced neoplasms in newborn Syrian hamsters.…”