EFFECT OF SIMPLE SUGARS ON NATURAL KILLING - EVIDENCE AGAINST THE INVOLVEMENT OF A LECTIN LIKE MECHANISM IN TARGET RECOGNITION

  • 1 January 1983
    • journal article
    • research article
    • Vol. 51  (3) , 517-524
Abstract
The spontaneous lysis of target cells sensitive to natural killer (NK) activity is accomplished in 2 distinct phases: binding between target and effector cells, and post-binding events leading to target cell destruction. To test the hypothesis that cell surface carbohydrate(s) might be involved in recognitive and/or lytic events, the binding and cytotoxicity of peripheral blood lymphocytes towards NK sensitive [human leukemia] K-562 targets was studied in the presence of simple sugars and after treatment of the targets with the antibiotic, tunicamycin. Lysis by peripheral blood lymphocytes was inhibited by N-acetyl glucosamine N-acetyl galactosamine and .alpha.-methyl mannoside in a dose-dependent manner under conditions where neither these sugars nor those (fucose, galactose) which had little effect on lysis inhibited the binding of effector cells to targets. Growth of K-562 in tunicamycin (which inhibits N-linked glycosylations occurring through the lipid intermediate pathway) with or without subsequent treatment with the enzyme neuraminidase, markedly reduced cell surface expression of sugars monitored by lectin binding. Treated cells showed no loss of NK susceptibility and were frequently more sensitive to lysis. Sugar inhibition profiles were the same as for untreated cells. Carbohydrates are apparently not the target sites of NK recognition but simple sugars may have an inhibitory action at a later stage of the lytic process.