title: Inhibition of natural killer cell lysis by natural killer-inhibitory substance: mechanism of suppression.
abstract: The mechanism of suppression of NK-mediated lysis by a soluble product of peritoneal cells (NK-IS, natural killer-inhibitory substance) was investigated. Pretreatment of effector cells resulted in depressed NK lysis while pretreatment of targets had no effect, indicating suppression is due to alterations in effector cell function rather than changes in target cells. NK-IS had no effect on the formation of conjugates between effectors and NK-susceptible targets. When NK-IS was added to effector-target cell mixtures after the binding step had been successfully completed, ensuing lysis was significantly depressed, confirming that NK-IS inhibited a postbinding lytic event. The degree of suppression caused by NK-IS was directly related to the duration of exposure to the inhibitory molecule. In addition, a preliminary temperature-dependent step of binding to and/or intracellular entry of NK-IS into effectors is required before suppression can occur. NK-IS prevents the activation of NK cell lysis by interferon and Corynebacterium parvum and effectively inhibits lysis mediated by already activated effectors. The potent suppression of NK lysis and prevention of interferon and C. parvum-mediated activation of NK lysis by a soluble product of peritoneal cells may explain the extremely low level of NK effector cell function within the peritoneal cavity.
mesh_terms: D000818:Animals; D002460:Cell Line; D002860:Chromium Radioisotopes; D007372:Interferons / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects; D009369:Neoplasms / Q000276:immunology*; D011425:Propionibacterium acnes / Q000276:immunology; D051381:Rats; D011920:Rats, Inbred WF; D013154:Spleen / Q000166:cytology; D013696:Temperature; D013997:Time Factors
chemical_list: D002860:Chromium Radioisotopes; D007372:Interferons