Fig. 4

Primary human monocytes survive at physiological temperature of the zebrafish in vitro and in vivo. (a) Primary human monocytes (blue) were injected into the hind brain of transgenic GFAP:GFP (astrocytes-green)/flk:mCherry (vessels-red) zebrafish larvae at 2 dpf. Micrographs show representative images where zebrafish was imaged serially over the course of 3 days post-injection at interval of 24 hours. (b) Plot (mean ± 95% CI) of average in vivo survival calculated for primary human monocytes obtained from larvae where the numbers of cells that survived over the course of 3 days for each larvae were normalized to the initial numbers measured one day post injection. Statistical analysis where * indicates a p value of p < 0.025 and *** indicates a p value of p < 0.0005 by successive t tests with Bonferroni correction, with n = 41 larvae for Day 1, n = 41 larvae for Day 2, and n = 4 larvae for Day 3. Scatter plots show values for individual zebrafish. Not all zebrafish survived to 5 days post injection. (c) Cells were either cultured at physiological temperature of humans (37 °C) or at physiological temperature of zebrafish (28.5 °C). Plot (mean ± SD) of average survival calculated for primary human monocytes obtained from n = 4 donors where the numbers of cells that survived over the course of 7 days were normalized to the original seeding density. Days in culture was a statistically significant factor in survival by two-way ANOVA with one degree of freedom (P < 0.0001), as was the temperature of culture (P = 0.0018).