Dialyzable transfer factor in experimental Chagas' disease: in vitro studies.

The dialyzable transfer factor (TF) was prepared from spleen and lymph node cells of either normal (TFn) or infected (TFi) mice with Trypanosoma cruzi. The ability of TFn and TFi in transferring cellular immunity to T. cruzi antigens was assessed by the macrophage migration inhibition assay and lymphocyte transformation test. The results obtained with these two immunological assays indicated that only TFi is able to transfer cellular immune responses. This phenomenon was antigen specific. The content of free amino acids in TFi preparation was higher than in TFn. However, our data indicated that the stimulation of lymphocyte transformation is not due to the increase in glycine and serine. This activity of TFi required the addition of T. cruzi antigens. Our findings support the hypothesis that TFi is derived from immune RNA.