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Interleukin 2 and interferon‐γ are not sufficient to induce natural killer‐like activity in human T cell clones

Abstract:

The role of interleukin 2 (IL2) and interferon (IFN)‐γ in the maintenance of natural killer (NK)‐like activity mediated by human cytolytic T cell clones was investigated. When cultured in standard supernatant (SN) obtained by phytohemagglutinin stimulation of human mononuclear cells (containing both IL2 and IFN activities), several mixed lymphocyte culture‐derived clones displayed cytolytic activity directed against the K562 cell line; in addition, some of these clones also lysed specific target cells bearing the sensitizing alloantigens. When cultured in IL 2‐containing SN obtained from the Jurkat cell line, the NK‐like activity was selectively abrogated within 4–5 days. However, by culturing cells again in standard SN the cytolytic activity was completely restored. The possibility that inhibitory molecules in Jurkat SN could be responsible for the loss of NK‐like activity was ruled out by experiments showing that cytotoxicity could be induced by mixtures of Jurkat and standard SN. In addition, a source of affinity chromatography‐purified IL2 also failed to maintain NK‐like activity. Moreover, addition of recombinant IFN‐γ in combination with purified IL2 did not prevent the loss of NK‐like activity. The present results indicate that neither IL2 nor IFN‐γ are sufficient to maintain NK‐like activity and suggest that other molecule(s) are required. Copyright © 1984 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim