Figure 2.

The percentages of SpTrf ⁺ small phagocytes in the coelomic fluid increase in response to Vibrio challenge. Three adult sea urchins were injected with heat-killed Vibrio diazotrophicus. Coelomic fluid (CF) was collected prior to injection (day 0) and after injection on days 1, 2, and 14. (A–D) Cells were incubated with a mix of three anti-SpTrf (formerly anti-Sp185/333) primary antibodies followed by incubation with a secondary antibody labeled with Alexa Fluor 488 (AF-488) to identified SpTrf⁺ cells. Nuclear staining with propidium iodine was used to exclude dead cells. Results for sea urchin 1 are shown. Percentages of live SpTrf⁺ coelomocytes from animal 1 at all time points are shown within the rectangular gate. SpTrf⁺ coelomocytes increase to the highest recorded level on day 2 post challenge and return to the basal level by day 14. (E) The mean of the percentages of SpTrf⁺ coelomocytes for the three individual animals at different time points are shown. Differences in the percentages of SpTrf⁺ cells over time for the individual animals were significant by Anova two factor analysis (p < 0.05). Additionally, the day 2 time point was analyzed compared to days 1 and 14 time points using Anova single factor (*indicates p < 0.05). Vertical bars indicate standard errors.