title: Human natural killer cell lysis of Salmonella typhi intracellularly-infected U937 cells.
abstract: Peripheral blood mononuclear cell (PBMC) cytotoxicity against S. typhi (wild type or mutant strain TYT1231)-infected U937 cells was significantly higher than its lytic effect against noninfected cells (control) at the various effector-to-target cell ratio used (30:1, 50:1 and 70:1). Natural killer cell activity [expressed as % specific lysis (mean +/- SEM); 30:1 (25.4 +/- 3.6, 25.1 +/- 4.2 and 16.3 +/- 3.3); 50:1 (27.8 +/- 3.7, 26.7 +/- 4.5 and 20.9 +/- 2.9) and 70:1 ratio (33.2 +/- 5.9, 29.4 +/- 4.2 and 22.8 +/- 2.8), respectively] appeared to be dependent on such ratios and independent of the S strain studied. Most (80%) of individual samples tested showed at least a 20% specific lysis increase over their own control; essentially no changes or smaller increases in NKC activity were observed in all other samples. Similar results were obtained when using highly purified NKC (HPNKC) preparations as effector cells [NKC activity (mean +/- SEM); 5:1 (46.2 +/- 4.7, 43.2 +/- 5.0 and 25.2 +/- 2.3) and 10:1 effector-to-target cell ratio (49.3 +/- 4.9, 44.7 +/- 5.2 and 27.2 +/- 2.6, respectively)]. All individual samples tested showed at least a 20% specific lysis increase over their own control. These results show that S. typhi-infected U937 cells are a significantly better target for NKCs than control cells and indicate that intracellular bacteria survival capacity is not a critical factor for infected cells becoming a NKC target.
authors: Department of Biochemistry and Molecular Biology, Faculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago, Chile.
authors: Dante
authors: D
authors: Miranda
authors: Javier
authors: J
authors: Puente
authors: Luz
authors: L
authors: Blanco
authors: Pablo
authors: P
authors: Jara
authors: Marion E
authors: ME
authors: Wolf
authors: Aron D
authors: AD
authors: Mosnaim
mesh_terms: D000328:Adult; D003602:Cytotoxicity, Immunologic; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D012485:Salmonella typhi / Q000502:physiology*; D020298:U937 Cells