Transfer with dialysable transfer factor of T-lymphocyte cytolytic response to tick-bone encephalitis virus antigen in naive mice.

Transfer factor activity was demonstrated in the dialysable extract from lymphocytes from outbred donor mice, in which immunization with live attenuated Langat (E5 "14") virus induced a stage of high resistance against challenge with virulent tick-borne encephalitis virus. Administered to naive inbred recipient mice, the extract conveyed in them specific cytolytic activity, exerted by their T lymphocytes, as demonstrated by the 51Cr release assay on tick-borne encephalitis virus-infected syngeneic L-929 cells.