Abstract: Objective To study the influence of albumin supplementation in the medium and the placement time outside the
incubator on the viability of isolated cytokine-induced killer (CIK) cells. Methods CIK cells labeled with anti-CD3-FITC and
anti-CD56-PE or with FQ-AE were observed under fluorescence microscope. The effect of albumin in the cell medium on the
cell viability was analyzed using flow cytometry with Annexin V-FITC after different time lengths of placement. Results The
clones of CIK cells from the patient with esophageal carcinoma were small and scattered in the medium, but the clones from
the patients with pancreatic cancer were large and densely distributed. CD3+CD56+ cells could be detected under fluorescence
microscope. The addition of albumin in the medium did not obviously affect cell apoptosis and death of CIK cells. CIK cells
placed outside the incubator for less than 90 min showed a significant lower apoptosis rate than the cells placed for 150 min,
whereas the cell death rate did not vary significantly with the placement time. Conclusion CIK cells from different cancer
patients present with different growth pattern of the cells clones. Labeling with anti-CD3-FITC and anti-CD56-PE allows
convenient counting of the newly generated CD3+CD56+ CIK cells and FQ-AE labeling can be used for quantitative assessment
of cell death. Albumin is not necessary in the medium of CIK cells. Prolonged placement (for over 90 min) of CIK cells outside
the incubator should be avoided, and the placement time should be shorten as much as possible.