An optimized protocol for Isolation, Expansion and Activation of Natural Killer cells from human Adipose Tissue

Abstract Adipose tissue has a heterogeneous cell population consists of adipocytes, mesenchymal stromal cells (MSCs), endothelial cells, pericytes, fibroblasts and etc. Also, it harbors immune cell types including macrophages, neutrophils, mast cells, dendritic cells, B cells, T cells, NK and NKT cells. In obese patients, there is a different cell homing pattern in AT. We have developed a protocol for NK cell isolation and expansion from AT as follows: 1) harvesting stromal vascular fraction, 2) negative selection of NK cells with MACS, 3) Expansion in a closed system bag on the constant shake, 4) Chemokine activation and 5) cytotoxicity evaluation test of the final product. The entire process with a population of ten billion CD16+ NK cells last only less than 16 days. We have noticed that a large population of NK cells entrapped in AT, while there is a decrease in NK cells count in their peripheral blood (PB) despite no changes in the total number of mononuclear cells. NK cell population harvested from AT has a different pattern in the expression of some cytotoxicity receptors. So, the AT is an important source for NK cell immunobiology studies.