Research Note: Detection of Fowlpox Virus Antigen in Tissue Culture by Fluorescent Antibody Technique

Abstract

The direct fluorescent antibody (FA) technique has been used to detect vaccinia antigens (6,8,9), small pox virus (2,4,5,7), rabbit pox virus (1), fowlpox virus (9), and Yaba Tumor Pox virus (10). In the present investigation, fowlpox viral antigens were detected in whole chicken embryo or chicken kidney cell cultures by a direct fluorescent antibody technique. Hyperimmune fowlpox virus antiserum was prepared in the chickens by cutaneous and intravenous inoculation of fowlpox virus strain ORT-101. This virus strain had been maintained by serial passages in CAM of developing chicken embryos. On cutaneous inoculation, the virus produced typical lesions of fowlpox in chickens. Specific antibodies against the fowlpox viral antigen were demonstrated by passive hemagglutination test and agar gel precipitation test. The serum was conjugated with fluorescein isothiocynate (General Biochemicals, Ohio) according to methods of Cherry and Goodman (3). The conjugated serum was adsorbed three times with acetone-extracted duck liver powder and stored at -60 C. In preliminary studies, both whole chicken embryo cell culture from nine-day-old embryos and kidney cell cultures from 19-dayold chicken embryos were grown in 10 X 150-mm rubber-stoppered sterile tubes containing 11 X 22-mm glass coverslips. Later, only chicken kidney cells were used. Confluent cell sheets were usually obtained on the coverslips in two to three days. A ten per cent suspension of fowlpox-virus-infected chorioallantoic membranes was made in Eagle's medium (Grand Island