Natural Killer Cells Stimulated With Pm21 Particles Expand And Biodistribute In Vivo: Clinical Implications For Cancer Treatment

Keywords

In vivo NK cell expansion; Membrane bound IL-21; Membrane particles; NK cells

Abstract

Background aims: Natural killer (NK) cell immunotherapy for treatment of cancer is promising, but requires methods that expand cytotoxic NK cells that persist in circulation and home to disease site. Methods: We developed a particle-based method that is simple, effective and specifically expands cytotoxic NK cells from peripheral blood mononuclear cells (PBMCs) both ex vivo and in vivo. This method uses particles prepared from plasma membranes of K562-mb21-41BBL cells, expressing 41BBL and membrane bound interleukin-21 (PM21 particles). Results: Ex vivo, PM21 particles caused specific NK-cell expansion from PBMCs from healthy donors (mean 825-fold, range 163-2216, n = 13 in 14 days) and acute myeloid leukemia patients. The PM21 particles also stimulated in vivo NK cell expansion in NSG mice. Ex vivo pre-activation of PBMCs with PM21 particles (PM21-PBMC) before intraperitoneal (i.p.) injection resulted in 66-fold higher amounts of hNK cells in peripheral blood (PB) of mice compared with unactivated PBMCs on day 12 after injection. In vivo administration of PM21 particles resulted in a dose-dependent increase of PB hNK cells in mice injected i.p. with 2.0 × 106 PM21-PBMCs (11% NK cells). Optimal dose of 800 μg/injection of PM21 particles (twice weekly) with low-dose interleukin 2 (1000 U/thrice weekly) resulted in 470 ± 40 hNK/μL and 95 ± 2% of total hCD45+ cells by day 12 in PB. Furthermore, hNK cells were found in marrow, spleen, lung, liver and brain (day 16 after i.p. PM21/PBMC injection), and mice injected with PM21 particles had higher amounts. Conclusions: The extent of NK cells observed in PB, their persistence and the biodistribution would be relevant for cancer treatment.

Publication Date

5-1-2016

Publication Title

Cytotherapy

Volume

18

Issue

5

Number of Pages

653-663

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.jcyt.2016.02.006

Socpus ID

84962046512 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84962046512

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