Increase of Lactic Dehydrogenase and Neutralizing Antibody in Plasma of Chickens Infected with Rous Sarcoma Virus

Increased concentrations of plasma lactic dehydrogenase (LDH) were reported in chickens with clinical leukosis(1). These authors suggested that flocks could be screened, using this test, as had previously been done in bovine leukaemia (2). This paper reports the increase of plasma LDH activity in chickens experimentally infected with the Bryan high-titre strain of Rous sarcoma virus (BS-RSV). The results indicate its general unsuitability as a screening test in comparison with neutralizing antibodies.

White Leghorn cockerels from our own leukosis-free stock were inoculated intravenously with BS-RSV which had been extracted from a wing-web tumour. A 10% (w/v) homogenate in 0.05 m-2-amino-2-hydroxymethylpropane-1,3-diol (tris) saline buffer pH 7.4 containing 10% (v/v) calf serum and one unit hyaluronidase (Koch-Light Laboratories, Colnbrook, Bucks.) per ml. was stirred for 1 hr at 22°. The extract was centrifuged at 200 g for 15 min, and the clear supernatant fluid was stored in a Linde liquid nitrogen refrigerator.