Chemotactic responses of hagfish (Vertebrata, Agnatha) leucocytes.

The chemotactic responses of hagfish leucocytes were tested using a variety of chemoattractants. Leucocyte migration was significantly enhanced by purified mammalian complement anaphylotoxin (C5a) and LPS-activated hagfish plasma. Checkerboard analyses confirmed that the responses of leucocytes to both of these chemoattractants were directed along concentration gradients (chemotaxis) and did not result from accelerated random movement (chemokinesis). Chemotaxis was undertaken by leucocyte fractions that were enriched in granulocytes, the predominant phagocytic cells of hagfish. The data suggest that chemotactic mechanisms may have been conserved during evolution to such a degree that mammalian chemoattractants can bind and activate chemotactic receptors on hagfish leucocytes. Moreover, hagfish appear to express plasma proteins that are structurally and functionally homologous to mammalian complement anaphylotoxins.