Abstract
A marked increase in natural killer (NK) activity is observed with lymphoid cells prepared from SJL/J mouse spleen and lymph nodes, in which a transplantable reticulum-cell neoplasm (RCN) is growing. The killer cells are non-adherent, non-phagocytic, relatively resistant to X-ray, and scarcely or only partially inactivated by treatment with anti-Thy 1.2 serum and complement. The killer activity is directed against a wide variety of tumor target cells, not requiring homology in histocompatibility, but is selective and not indiscriminate. Kinetics of in vivo development on NK activity, competitive inhibition of in vitro cytotoxicity by target cells and their membrane extracts are described. The NK activity appears to increase in parallel with the infiltration and growth of RCN in these organs. No such augmented NK activity was observed with other types of tumors that grew in these organs of SJL/J mice. (C57BL/6 X SJL/J)F1 mice pretreated with silica to abrogate Hh restriction and subsequently injected with RCN of SJL/J (H-2s) origin supported the growth of transplanted RCN. The high NK activity associated with this RCN was markedly reduced by in vitro treatment with anti-H2b serum plus complement, indicating the host origin of NK cells. However, the close association of RCN growth with elevated NK activity may indicate a special function of RCN in promoting NK activity by an unknown mechanism(s) of cellular interactions.
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