Cellular aspects of Holothuria polii immune response

The cellular events in Holothuria polii after injection of sheep erythrocytes into the coelomic cavity are various and include recruitment of a large number of coelomocytes from hemopoietic areas, phagocytosis by amoebocytes, and the formation of a complex, active structure, the brown mass, through which the phagocytic residual products are cleared. Of interest is the finding that brown masses are positive to Schmorl's reaction, suggesting a possible melanin presence. The coelomocyte lysates are also able to oxidize DOPA, an intermediate product of one melanin synthesis pathway.