Induction of avidin in chickens infected with the acute leukemia virus OK 10

The presence of avidin, a progesterone-dependent oviductal glycoprotein, was studied in viral tumors. Newborn chickens were infected with the acute leukemia virus OK 10, and the first tumors occurred within 2–3 weeks. Avidin was assayed using a [14]biotin-binding method and radioimmunoassay. In the control chickens, avidin concentrations were <0.3 μg/g in the plasma and <1.5 μg/g in various tissues including the immature oviduct. In the OK 10 virus-infected chickens, no significant induction was observed during the acute infection or any time thereafter if no tumors were seen. In chickens that developed tumors, avidin concentrations were significantly increased in tumorous tissue only located in the mesenterium and occasionally in the oviduct. In tumors occurring elsewhere (kidney, ovary, muscle, testis, liver, colon) avidin concentrations were not elevated. Tumor-associated avidin had extraordinary biotin-binding capacity after treatment at +90° C similar to the progesterone-dependent avidin, whereas antibody-binding properties suggested that tumor-associated avidin may have a some-what altered antigenic structure.