In this classification, undifferentiated cells are composed of hemoblasts, also called lymphocytes or lymphocyte-like cells, as well as of differentiating cells.
When focusing on circulating hemocytes, we observed an incipient decrease in the population of morula cells, accompanied with an increase in the populations of hemoblasts, hyaline amebocytes, and granular cells (Fig.
5D, G), while numbers of both hemoblasts and differentiating cells return to preinjury levels (Fig.
In addition, we followed the quantity and location of each type of hemocyte during WBR, finding that regeneration progresses through a rapid healing response, an increased activity of hemoblasts, the recruitment of macrophage-like cells, and finally their clearing from the hemolymph.
Table I Hemoblast cell-specific immunoreactivity using anti-FGF2 in Molgula pacifica juveniles Cell type(*) and staining(**) Stage Antibody (Day) me tu ae hb ccm FGF2 2 - - - - - 3 - - - (+) - 4 - - - (++) - 5 - - - (+++) - EGF 2 - - - - - 5 - - - - - * Me, mantle epidermis; tu, tunic; ae, ampullar epidermis; hb, hemoblast cells; ccm, central cell mass.
As previously described in detail (1), hemoblast cells are pumped into the lumen of growing ampullae by rhythmic contraction waves generated by the ampullar walls, and hemoblast cells are often observed in the tip region of ampullae.