Changes in number and density of large granular lymphocytes upon in vivo augmentation of mouse natural killer activity
Santoni, A.; Piccoli, M.; Ortaldo, J.R.; Mason, L.; Wiltrout, R.H.; Herberman, R.B.
Journal of Immunology 134(4): 2799-2810
1985
ISSN/ISBN: 0022-1767 PMID: 2579157 Document Number: 243569
Natural killer (NK) activity of mice as well as humans and rats was clearly associated with large granular lymphocytes (LGL). To better understand the effects of interferon (IFN) and IFN inducers on natural killer (NK) cells, the LGL in the spleens of normal and boosted mice were compared. Cells were fractionated by centrifugation on discontinuous Percoll density gradients, and each fraction was tested for NK activity against YAC-1 targets and for the presence of LGL. In vivo treatment with [Propionibacterium acnes] (0.7 mg/mouse, i.p., day -3), MVE-2 [maleic vinyl ether-2] (25 mg/kg, i.p., day -3), poly I:C (4 mg/kg, i.p., day -3), or IFN (105 U/mouse, i.p., day -1) resulted in a marked augmentation and a change of distribution of cytotoxic activity. Most of the NK activity of boosted spleen cells was associated with lower density fractions 1 and 2; active normal spleen cells had somewhat higher density (fractions 2 and 3). In parallel to their increased reactivity, the boosted spleens had a marked increase in the percentage of LGL, particularly in fractions 1 and 2. The augmented activity appeared to be mediated by the LGL, because treatment with anti-asialo GM1 or anti-Thy-1.2 plus complement reduced NK as well as the number of LGL. Evidently, IFN-mediated boosting of NK activity in the spleen is due to an increase in the lower density LGL, as well as to an increase in the function of preexisting NK cells.