Antigen-specific transfer factor from mice immunized with an attenuated flavivirus: augmentation of inducing activity in semipurified splenocytic dialyzates.

Three large batches were prepared of lyzed splenocytic leukocyte dialyzate from SPF outbred mice, immunized with a live attenuated virus from the tick-borne encephalitis (TBE) complex. Total mass of freeze-dried dialyzates was 1.73 g. One mg of respective batches contained 2 X 10(5), 2 X 10(4) and 2 X 10(3) units of the transfer factor, specific for the flavivirus group-antigen, as estimated according to the capacity to induce specifically cytotoxic T-cells in the recipient C3H mice. The amount of protein and orcinol-reactive material (purine-bound ribose), the presumed components of the inducer's substrate, ranged in individual dialyzates from 9.9-12.4 and 0.72-0.80% of their dry mass. Materials from each batch obtained after double precipitation by ethanol were subjected to permeation chromatography on Sephadex G-25 columns and subsequent lyophilization of the peak with specific inducing activity. The final product represented on average 3.7 per cent of dry mass of the starting material. In comparison to the crude material, in one mg of the final product the protein and the orcinol-reactive material were reduced by 80 and 37 per cent, respectively, but an increment in the antigen-specific inducing capacity comprising 2-3 log10 units was observed. These findings add to the concept that a) macromolecules carrying the inducing activity can be separated from other constituents of the crude dialyzate and b) an increase in antigen-specific inducing activity titre was, besides partial concentration, mainly due to removal of suppressor or inhibitory factor(s) present in the crude dialysates and probably acting in vivo.