Antibody-enhanced phagocytosis of lamprey polymorphonuclear leucocytes against sheep erythrocytes

Centrifugation on Ficoll-Paque of the blood from the Arctic lamprey, Lampetra japonica, yielded a uniform population of leucocytes containing about 90% polymorphonuclear leucocytes (PMNs). The PMNs showed a significantly enhanced phagocytic activity in vitro against sheep erythrocytes (ES), provided they were opsonized with the specific lamprey antibody (AL) against ES. This enhanced phagocytosis by PMN was more active at 4 degrees C than 15 degrees C, being dependent on Ca++; the opsonic activity of lamprey antibody was not replaced by bullfrog antibody. By the use of electron microscopy, it was found that the PMNs possess a well developed Golgi complex and rough ER, as well as highly variable cytoplasmic granules. Observations by both SEM and TEm revealed the formation of prominent pseudopodia, lamellipodia and phagosomes by the PMN during the process of engulfing erythrocytes.