Suppression of natural killer cell activity by chicken alpha-fetoprotein in Japanese quails.

Spleen cells taken from quails treated with chicken alpha-fetoprotein (Ch-AFP) showed reduced natural killer (NK) activity as did spleen cells taken from quails treated with chicken amniotic fluid (ChAmF) in which the presence of Ch-AFP was demonstrated by a gel precipitation test. The Ch-AFP-induced reduction of NK activity was shown to be mediated by suppressor cells. In addition, Ch-AFP-treated quails developed tumors with shorter latent periods than those of the tumors that developed in untreated quails after inoculation with Rous sarcoma virus, as was true for ChAmF-treated quails.