AUGMENTATION OF LYMPHOCYTE TRANSFORMATION TO TUBERCULIN PPD.

There is recent interest in whether dialysable transfer factor can specifically increase immune responses when added to lymphoid cells in vitro. This report demonstrates that transfer factor preparations (human leucocyte dialysates) 'augment' rather than 'transfer' lymphocyte transformation responses (DNA synthesis) to tuberculin PPD in vitro and that the magnitude of this augmentation is proportional to the level of DNA synthesis induced by PPD in the absence of added transfer factor. Experiments showed that transfer factor preparations from Mantoux-positive or Mantoux-negative 'donors' were equally effective in augmenting 'recipient' lymphocyte trans- formation responses to PPD. Thus the extent of augmentation was related, not to the tuberculin sensitivity of the transfer factor donors, but to that of the recipients. In the absence of tuberculin PPD, transfer factor preparations sometimes stimulated lymphocyte DNA synthesis, but the extent of this was small and inconstant. The results therefore provide evidence for an antigen-dependent, but not an antigen- specific effect of transfer factor in increasing lymphocyte DNA synthesis in vitro. It is suggested that leucocyte dialysates contain an augmenting factor which may facilitate the response of antigen-sensitive cells to PPD in vitro, or may facilitate the recruitment into DNA synthesis of cell populations responding to mitogenic lymphokine produced during lymphocyte transformation. [ABSTRACT FROM AUTHOR]