Abstract

The diffusion chamber technique permitted the demonstration of specific antibody formation in x-irradiated recipients of such chambers filled with normal lymph node cells and a cell-free homogenate of macrophages which had been incubated in intro with T2 bacteriophage. The activity of the cell-free homogenate was retained in its RNA fraction isolated by means of the phenol method. No antibody formation occurred if such RNA was treated with RNAase. On sucrose gradients (5 to 20 per cent), the active RNA was found to be present in the top third layer. The question of the possible presence of antigen complexed to the RNA is discussed.