The theory of immune surveillance of Thomas and Burnet stated in part that antigenic
differences between neoplastic and normal cells provide the stimulus for their destruction by
cells of the immune system. Burnet pointed to the T lymphocyte as the cell which mediated
this surveillance. The existence of some form of surveillance in cases of no T lymphocyte
functioning presents the possibility that surveillance, if present at all, is mediated by non T
cells. Cells identified as naturally cytotoxic killer (NK) cells appear to have properties …

The functioning of natural killer (NK) cells as immune surveillance effector cells against
tumors is explored. In part I (J. Math. Biol. 12, 363–373 (1981)), it was predicted that
susceptible tumors would be eliminated if they have parameter λ 0 value negative. They
would not be eliminated if λ 0> 0. As the λ 0< 0 result was local, one expected either that
tumors of all sizes with λ 0< 0 will be eliminated (global stability) or that tumor population will
go to zero if in a domain of attraction of the critical point which is not all of the positive …