Biological Characterization of Commercial Recombinantly Expressed Immunomodulating Proteins Contaminated with Bacterial Products in the Year 2020: The SAA3 Case

Figure 9

Mu rSAA3_pur synergizes with CXCL8 in neutrophil activation. Activation of human neutrophils was assessed via shape change assays. Neutrophils were stimulated for a period of 3 min with different concentrations of CXCL8 (1 or 3 ng/ml), mu rSAA3_pur (30-3000 ng/ml) or were left untreated. After fixation of cells, non-activated resting (round) and activated (blebbed and elongated) neutrophils were counted microscopically by 2 individuals independently. (a) Data represent the derived from 4 independent experiments. Statistically significant activation of neutrophils (compared to controls) and statistically significant synergy (compared to the sum of the values when both agonists are tested separately), determined by the Mann-Whitney test, are indicated by asterisks () and daggers (^†), respectively. (b) Phase contrast image (20x magnification; scale bar: 20 μm) of one representative experiment illustrating the morphological change of neutrophils following stimulation with buffer (control), CXCL8 (3 ng/ml), mu rSAA3_pur (3000 ng/ml) or a combination of CXCL8 and mu rSAA3_pur are shown.

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