Loss of tumorigenicity following in vitro MuLV infection is associated with induction of peritoneal natural killer cell activity.

Infection by an attenuated replication-competent murine retrovirus (Friend leukemia virus-FLV4), but not other non-transforming retroviruses, stimulated rejection of transplantable thymomas (RL-cell line) and subsequent tumor immunity in syngeneic mouse recipients. FLV-infected RL-cells (RL-FLV) were unaltered in their in vitro growth, and grew progressively to kill sublethally irradiated animals and nude mice. Primary RL-FLV rejection was due to induction of increased natural killer (NK)-cell activity limited to peritoneal sites of tumor inoculation with a minor cytolytic macrophage population. Syngeneic mutant beige (NK-deficient) mice similarly rejected RL-FLV cells with increased peritoneal NK-cell activity and acquired immunity to the parental RL-tumor. While RL-FLV stimulated far greater peritoneal NK activity than did other tested retrovirus-infected RL-cells, the inherent susceptibility of these cells to lysis by normal NK cells was not altered by virus. RL-FLV induced NK effectors showed an indiscriminate lysis pattern that was independent of target cell type and retrovirus expression.

Duke Scholars

Author Dani Paul Bolognesi Surgery, Surgical Sciences

Author Kent James Weinhold Surgery, Surgical Sciences