Generation of lymphokine-activated killer cells by adherent LGL phenotype cells and non-adherent T lymphocytes.

Abstract

In this work we separated human blood lymphocytes (PBL) in two populations (A-LAK and NA-LAK cells) by the adherence plastic method. A maximum adherence of cells was obtained after 2 days of PBL incubation in LAK medium containing 500 U/ml rIL-2. The A-LAK cells had LGL phenotype but 40% of them had a macrophage phenotype marker and less than 20% weakly expressed a T-cell marker. This population, when reincubated in culture, produced an increasing titre of interferon. At the same time, a significant NK activity against K562 target cells was measured just after enrichment; these enriched adherent cells also developed an increased LAK activity against DAUDI cell lines, ninefold more at 6 days than when assayed just after enrichment. In contrast, 75% of the NA-LAK enriched cells expressed T-cell marker; these produced two- to threefold less interferon than A-LAK cells at all time-points. The NA-LAK lymphocytes enhanced principally LAK activity measured by 70% lysis against DAUDI target cells tested at 6 days of culture. Further studies are in progress to determine the nature of the effector cells that mediated LAK activity.